Mark V 90 watt tube rolling

[user 83127]

PLEASE and thank you, not one mention of this topic. Everyone talks about the V-4 and V-6 AT7 "Mod" but not one person points out the obvious. The V-4 and V-6 positions are THE ideal positions for tube rolling. I find that V-4 gives you marked changes to the gain of channel one and two and V-6 gives you the desired effect for the red or channel three. I do not know why these are important to the sound, by reading the schematic you would THINK that v-3 and v-2 were a LOT more important but there it is. I currently have a Gold Lion 12ax7 in v-6 and a chinese 12ax7b in v-4 (I have Gold Lion in every other position except PI...which is a custom graded Mesa 12ax7-a Russian (Find one of those). The Gold Lion sounded a little stiff in the first two channels, EH was DARK, I had JJ's in and they were ok so settle on Chinese for now, although I have a feeling I would LOVE Tung Sol in this position (v-4)...and the Gold Lion in V-6, forget about it!!!. Good luck. (Which tube you use matters, I had a Gold lion in v-6 and it was NOISY...changed it and now the gain is tight and noise free...same tube and it isnt exactly like Gold Lion are cheap...but there it is...some suck even when you pay an ignorant premium)

 

[bandit2013]

I am assuming you are not referencing the V90.
If you were referencing the 90W version of the Mark V, then V4, V5 and V6 are basically related to CH3 only with exception of half of the preamp tube (other triode not used on the CH3 circuit) are associated to the reverb send/receive and the FX return.

With the 90W model, V5A is the first gain staged in the lead drive circuit. It feeds into V4B that creates an asymmetrical distortion characteristic. With some V90's, the CH3 characteristic may be too bright or ice pick and does not matter at what volume or gain level you are using. The JAN/Phillips 12AT7 preamp tube will have the same low end gain as a 12AX7 tube, it is the difference in the higher frequency gain that matters. A tube with more roll-off in the upper frequency range like the JAN/Phillips 12AT7 will aid in reduction of the upper frequency range as well as the associated harmonics that lend to the ice pick tone. Note that not all 12AT7 have the same behavior. The Mesa Chinese verision was excessively bright. I also tried the Tung Sol 12AT7 and found similar result. The JAN/Phillips 12AT7 had a more predictable characteristic. On the other hand, a NOS RFT12AT7 was much darker in character. Not sure if I did much with that.

V2 is only associated with the CH2 preamp and is not used on CH1 or CH3 (reference is the 90W version of the Mark V). V3 on the other hand is also used on all channels. It is the channel master for CH1, also associated with CH2 channel master volume. CH3 only uses a single triode of V3(a) and then routs the signal path to V6A for its additional voicing. Note that there are several attenuator voltage divider sections between V3A and V6A so it is not a major gain contributor.

The Mark V90W model does respond quite well to various preamp tubes. Roll away and find what works best for you. No fear as the V90W does not have any cathode follower circuitry to be aware of. I would not doubt the other platforms for the V are similar. However, they do not share the same preamp tube topography so the gain stages may not be laid out the same as the bigger Mark V.

 

[user 83127]

Sure...that is what the schematic reads like (I did see it and felt the same way, I EVEN REFERENCED IT IN MY POST)...THAT IS NOT HOW THE AMP BEHAVES...MINE I only get ANY distinction when I roll the tubes as stated...That's WHY I POSTED...I have owned my amp for going on 6 years now and these are the ONLY differences I get tube rolling...and I have tried each and EVERY STAGE (I believe that Mesa is GENUIS at convoluted schematics and their circuit is MOSTLY bass ackwards at least on the schematics). So you have at it. and for those that want to try what I suggested...save yourself YEARS of banging your head on the wall and swearing this is one **** amp for tube rolling. No offense intended.

 

[user 83127]

I am assuming you are not referencing the V90.
If you were referencing the 90W version of the Mark V, then V4, V5 and V6 are basically related to CH3 only with exception of half of the preamp tube (other triode not used on the CH3 circuit) are associated to the reverb send/receive and the FX return.

With the 90W model, V5A is the first gain staged in the lead drive circuit. It feeds into V4B that creates an asymmetrical distortion characteristic. With some V90's, the CH3 characteristic may be too bright or ice pick and does not matter at what volume or gain level you are using. The JAN/Phillips 12AT7 preamp tube will have the same low end gain as a 12AX7 tube, it is the difference in the higher frequency gain that matters. A tube with more roll-off in the upper frequency range like the JAN/Phillips 12AT7 will aid in reduction of the upper frequency range as well as the associated harmonics that lend to the ice pick tone. Note that not all 12AT7 have the same behavior. The Mesa Chinese verision was excessively bright. I also tried the Tung Sol 12AT7 and found similar result. The JAN/Phillips 12AT7 had a more predictable characteristic. On the other hand, a NOS RFT12AT7 was much darker in character. Not sure if I did much with that.

V2 is only associated with the CH2 preamp and is not used on CH1 or CH3 (reference is the 90W version of the Mark V). V3 on the other hand is also used on all channels. It is the channel master for CH1, also associated with CH2 channel master volume. CH3 only uses a single triode of V3(a) and then routs the signal path to V6A for its additional voicing. Note that there are several attenuator voltage divider sections between V3A and V6A so it is not a major gain contributor.

The Mark V90W model does respond quite well to various preamp tubes. Roll away and find what works best for you. No fear as the V90W does not have any cathode follower circuitry to be aware of. I would not doubt the other platforms for the V are similar. However, they do not share the same preamp tube topography so the gain stages may not be laid out the same as the bigger Mark V.

Here is even more weirdness. Explain this if you will/can. I went back today and Attempted to verify if in fact the tube I was rolling was v-4, so I plucked it out and turned off the FX loop and lo and behold the amp still worked , so yup, v-4, effects return....yet I rolled v-3 and nothing, I rolled v-5 and v-2 and yup..nothing...I rolled v-4 and got the desired change in gain structure (I am rolling chinese to Gold lion and JJ, so all three major tube types). Now it behaves as the schematic states EXCEPT THE TUBE CHANGE HAS A DEFINATE EFFECT IN V-4 position...NO WHERE ELSE...I cant figure it but am going with it anyways, because what the **** else can I do...the only thing I can state is I am using the effects loop as I run my Mark V to a G Force processor and back to the power amps for stereo outs..the change in tone hits BOTH power amps the same way so if it were the effects going back to the amp changing the tone then the Marshall I use as a power amp would see a different output (or the original output..not the changed one from tube rolling..yet it is changed)..there has to be something changed from the schematic or this would not be the case

 

[bandit2013]

Perhaps I may be confused on your statements above. Some of the descriptions you provided make me think you have a different Mark amp in the 25 or 35W models. They do not have the same preamp design or share anything in common but the product name. Mark V. The V90W preamp design is unique and is not shared with the other models of Mark V. If yours is a 90W Simul-class model with the 90W/45W/10W power modes and also has the 5U4B rectifier tube, I would assume Mesa redesigned the entire amp which I doubt is the case here. If it is 9 years old, that would place it at 2014 model year. That is when the Mark V:25 came out. Also, you did not mention what you have in the V7 position. I assume it is an EL84 if it is not the V90. The V90 has the phase inverter as the V7 position. In other words, I doubt there is much you can do with the V25 or V35 in terms of tuning with preamp tubes. Use what sounds best for you. I found the same issue with the JP2C, did not make any difference what preamp tubes I used, the Mesa 12AX7 (selected JJECC83s) seemed to perform the best. Russian tubes made it motor boat, Chinese tubes were fuzzy. NOS tubes were too damn bright. No big deal. the stock tubes are great. Same would apply to the Badlander and Triple Crown. May as well throw in the MWDR. Not much of a change. Roadster and Royal Atlantic were somewhat tunable with preamp tubes. I no longer have the Mark III or Mark IVb but I did roll in some EH 12AX7 tubes in the IV. Thought the Mesa Chinese square foil getter tubes sounded the best in that amp (old stock from 1990). The Mark V90W thus far is the most responsive amp based on preamp tubes used. I cannot comment on the V25 or V35 as I do not own them or ever played through one.

I actually stopped paying any attention to the Mark V forum since too many people are calling their mark V just Mark V. I had to adopt the use of V90 in reference to the amp I have. Others should do the same V25 or V35. There is no common ground with the amps other than the generic Mark V.

Answer this question first: Which diagram matches the Mark V you have? If it is 9 years old you either have the 90W or 25W (2014) as the 35 came out a year later (2015).



This is the rear view of the Mark V90W. It it is not this amp you are tube rolling, not sure what to expect. I have the V90W and it is not the same preamp as the V25 or V35. If you have the schematic for the V25 or V35, can you share it with me in a private message. Just curious to see how the design is different from the V90. I just want to see the preamp section, don't care about the dyna watt power section.

 

[user 83127]

Perhaps I may be confused on your statements above. Some of the descriptions you provided make me think you have a different Mark amp in the 25 or 35W models. They do not have the same preamp design or share anything in common but the product name. Mark V. The V90W preamp design is unique and is not shared with the other models of Mark V. If yours is a 90W Simul-class model with the 90W/45W/10W power modes and also has the 5U4B rectifier tube, I would assume Mesa redesigned the entire amp which I doubt is the case here. If it is 9 years old, that would place it at 2014 model year. That is when the Mark V:25 came out. Also, you did not mention what you have in the V7 position. I assume it is an EL84 if it is not the V90. The V90 has the phase inverter as the V7 position. In other words, I doubt there is much you can do with the V25 or V35 in terms of tuning with preamp tubes. Use what sounds best for you. I found the same issue with the JP2C, did not make any difference what preamp tubes I used, the Mesa 12AX7 (selected JJECC83s) seemed to perform the best. Russian tubes made it motor boat, Chinese tubes were fuzzy. NOS tubes were too **** bright. No big deal. the stock tubes are great. Same would apply to the Badlander and Triple Crown. May as well throw in the MWDR. Not much of a change. Roadster and Royal Atlantic were somewhat tunable with preamp tubes. I no longer have the Mark III or Mark IVb but I did roll in some EH 12AX7 tubes in the IV. Thought the Mesa Chinese square foil getter tubes sounded the best in that amp (old stock from 1990). The Mark V90W thus far is the most responsive amp based on preamp tubes used. I cannot comment on the V25 or V35 as I do not own them or ever played through one.

I actually stopped paying any attention to the Mark V forum since too many people are calling their mark V just Mark V. I had to adopt the use of V90 in reference to the amp I have. Others should do the same V25 or V35. There is no common ground with the amps other than the generic Mark V.

Answer this question first: Which diagram matches the Mark V you have? If it is 9 years old you either have the 90W or 25W (2014) as the 35 came out a year later (2015).

View attachment 1492View attachment 1493View attachment 1494

This is the rear view of the Mark V90W. It it is not this amp you are tube rolling, not sure what to expect. I have the V90W and it is not the same preamp as the V25 or V35. If you have the schematic for the V25 or V35, can you share it with me in a private message. Just curious to see how the design is different from the V90. I just want to see the preamp section, don't care about the dyna watt power section.

View attachment 1497

Sorry about the hostility (post deleted)...turned on amp today and lost channel three...turns out the v-4 tube broke and half my amp went out (channels 1 and 2 unaffected) so this brings in the question (DEFINITLEY 90 watt manufactured and left the factory in 2016...july I believe). Went back to a 12at7 in this position because I had a green label jan phillips and why not...I get gain changes in 1, 2 and 3 ...I swapped the v-4 and v-6 (Gold Lion) and got the appropriate change in gain to all three (went back to stock on one and two and changed on three only not so much, so decided the best bang for the buck was to change v-4 and this affects all three channels YET SHOULD NOT...I am left wondering WHY )(WTF actually)? Definitely the slot is working as it is stated the V-4 only affected the channel three when the sound went out,and only because I had the effects loop active I assume...yet when I put in the 12at7 it most definitely effects channels one and two (I get the same slowing of the peaks effect I would expect from a low gain tube, the same slowing you get on channel three (WHICH SHOULD by schematic be the ONLY channel effected by this move)...as I am saying this I can think of one test, to put the amp into loop bypass and see if the tube being removed from the circuit PHYSICALLY changes anything..you know what... i a back to the disenchantment phase again with this amp..it is a frustrating pos that NEVER lived up to the hype (heck...they never even really made a try to reproduce the actual circuits...what should I haved expected )...and they cant even be bothered to maintain or mod it(and the new ones they got rid of the decent warranty) anyone want to buy an overvalued pos

 

[bandit2013]

I see now. You have a mark V90. Sorry if I have been rude in my comments as I found some a bit confusing.

There is a schematic you can find online for the V90, it is the original version of the amp as of 2009. Some parts are not listed on the schematic as they made some hard mods to the assembly. Mesa did update the design in 2010 but that is only available through certified tech and they are legally bound not to share the documents. However, the basic design (at least I found with the 2012 V) was much the same as the schematic dated 2009 but has changes in the tone stack for CH3.

If you run the amp in hard bypass mode (turning off the FX loop) you will get a bypass on V6B triode.
Since the tubes that contain the lead drive circuitry V5A -> V4B (I wrote this in the signal path) they are only associated with CH3. Reason you may get some influence on CH1 and CH3 is the reverb as V4A is the reverb send and V5B is the reverb return. You can disable the reverb if you so desire or just unplug it from the amp, easier just to turn it off.

V1 (both triodes) will be in all channels. The tone stacks for CH1 and CH3 sit between V1A and V1B triodes. The gain control for CH1 is located here following the CH1 tone stack. CH3 association here is the tone stack only. As for CH2, signal path is V1A -> V2A -> tone stack ->V1B. Any change in V2 will only influence CH2 and will have no effect on CH1 or CH3. You can remove it and you will get sound on CH1 and CH3. The gain control for CH2 is on the front end of V2A.

What follows V1B are some relays that will bypass V5A and V4B. That circuitry has some filtering and also provides the reverb taps for CH1 and CH2. The next triode in signal path would be V3A. So if you did remove V4 and V5, the effect would be no reverb on any channel, and no sound from CH3.
The lead drive has the gain control on the front end of V5A. This clipped signal is now fed into V4B which is the highest gain of any stage in the amp.

The lead drive circuit does flow into V3A by relay connection as do the other two channels. However, the signal path for CH3 gets diverted to V6A before getting pushed into the GEQ circuit.
V3A will feed into V3B for CH1 only. V3B is where the CH1 master volume is located and is a grid control. CH2 has a bypass for V3B and has a plate driven CH2 master volume. The signal paths here are then fed into the GEQ circuit.

Note that the GEQ circuit is used to create the signal level for the FX send. It will always be in the signal path even when the GEQ is bypassed (front end and accumulator circuits from the GEQ are not bypassed). In hard bypass mode, V6B will not be in the circuit. The signal level from the GEQ (this does not include the send level control) will be directly driven into the phase inverter. In active mode, the V6B will be used as the rebuilding buffer to bring the signal level up to the phase inverter requirement.

Reason for the FX tone suck, it may be in part to the processor used in the FX loop. Some is due to the improper impedance of the send circuit. Impedance it too high and does not make for a good signal source. There are some good effects that work well with the V fx loop. I have struggled to find products that actually work without compression effect due to overdriving the input buffers and such. Strymon stuff actually worked well. After that success, I have been using their gear with all of my other amps. I barely use the Mark V90 as I only have a tolerance for 20 minutes before its tone gets on my nerves. A specific midrange content I have not been able to avoid. Also mine is super bright in tone, tweed is an ice pick, Edge just sounds like crap (it is actually decent with a 7 string though). and most of CH3 was an ice pick until the JAN/Phillips 12AT7 in V4 allowed for use of the treble and gain control. Normally had to dial them mostly out due to ice pick characteristics.

The other way to defeat the ice pick was speaker choice. Celestion Creme 90W Alnico did a really good job on filtering the higher frequencies and eliminated the ice pick on CH3. Did not favor CH1 or CH2 with that speaker. The Redback speaker was similar but had a better sound on CH1. I personally did not accept the Mark V90 in any favorable feelings. I tried to like it but just could not adapt.

For me the Roadster, Royal Atlantic, JP2C, Multi-watt Dual Rec, Triple Crown, and Badlander were the amps I desired. RA and BAD are my two favorites. JP2C falls in third. Since my experience with the Mark V90 did not live up to my expectations (tone or reliability) when compared to the Mark III that I used for over 24 years and the Mark IVb I ran for 12 years. Both were combos. I wanted a head for the 412 cab and got that in the Mark V. Not only did the amp overheat and burn up power tubes in less than 20 minutes if I was lucky. I had to find alternative tubes that would survive. Tung Sol 7851A lasted a good 6 months before loosing tone. Gold Lion KT77 ran a good 8 months at full power. The ideal tube I could not kill was the SED =C= 6L6GC. Anyhow, after all of that, I am not confident to get the Mark VII. Would I have the same headaches? Tube issues? Not sure. I thought I was the only one with the lemon. I still have it. Converted it from head to combo to keep the chassis cooler (found out the bias was messed up and corrected it, still not right but does not burn out Mesa tubes anymore). Made some hard mods to fix some of the ***** tones and abundance of higher order harmonics that lends to shot noise (ice pick). I believe some of this is related to the GEQ circuit. The V90 is not a door stop in the dining room. Have not powered it up since? about the time I gave up on the forums a few years ago.

 

[user 83127]

I see now. You have a mark V90. Sorry if I have been rude in my comments as I found some a bit confusing.

There is a schematic you can find online for the V90, it is the original version of the amp as of 2009. Some parts are not listed on the schematic as they made some hard mods to the assembly. Mesa did update the design in 2010 but that is only available through certified tech and they are legally bound not to share the documents. However, the basic design (at least I found with the 2012 V) was much the same as the schematic dated 2009 but has changes in the tone stack for CH3.

If you run the amp in hard bypass mode (turning off the FX loop) you will get a bypass on V6B triode.
Since the tubes that contain the lead drive circuitry V5A -> V4B (I wrote this in the signal path) they are only associated with CH3. Reason you may get some influence on CH1 and CH3 is the reverb as V4A is the reverb send and V5B is the reverb return. You can disable the reverb if you so desire or just unplug it from the amp, easier just to turn it off.

V1 (both triodes) will be in all channels. The tone stacks for CH1 and CH3 sit between V1A and V1B triodes. The gain control for CH1 is located here following the CH1 tone stack. CH3 association here is the tone stack only. As for CH2, signal path is V1A -> V2A -> tone stack ->V1B. Any change in V2 will only influence CH2 and will have no effect on CH1 or CH3. You can remove it and you will get sound on CH1 and CH3. The gain control for CH2 is on the front end of V2A.

What follows V1B are some relays that will bypass V5A and V4B. That circuitry has some filtering and also provides the reverb taps for CH1 and CH2. The next triode in signal path would be V3A. So if you did remove V4 and V5, the effect would be no reverb on any channel, and no sound from CH3.
The lead drive has the gain control on the front end of V5A. This clipped signal is now fed into V4B which is the highest gain of any stage in the amp.

The lead drive circuit does flow into V3A by relay connection as do the other two channels. However, the signal path for CH3 gets diverted to V6A before getting pushed into the GEQ circuit.
V3A will feed into V3B for CH1 only. V3B is where the CH1 master volume is located and is a grid control. CH2 has a bypass for V3B and has a plate driven CH2 master volume. The signal paths here are then fed into the GEQ circuit.

Note that the GEQ circuit is used to create the signal level for the FX send. It will always be in the signal path even when the GEQ is bypassed (front end and accumulator circuits from the GEQ are not bypassed). In hard bypass mode, V6B will not be in the circuit. The signal level from the GEQ (this does not include the send level control) will be directly driven into the phase inverter. In active mode, the V6B will be used as the rebuilding buffer to bring the signal level up to the phase inverter requirement.

Reason for the FX tone suck, it may be in part to the processor used in the FX loop. Some is due to the improper impedance of the send circuit. Impedance it too high and does not make for a good signal source. There are some good effects that work well with the V fx loop. I have struggled to find products that actually work without compression effect due to overdriving the input buffers and such. Strymon stuff actually worked well. After that success, I have been using their gear with all of my other amps. I barely use the Mark V90 as I only have a tolerance for 20 minutes before its tone gets on my nerves. A specific midrange content I have not been able to avoid. Also mine is super bright in tone, tweed is an ice pick, Edge just sounds like crap (it is actually decent with a 7 string though). and most of CH3 was an ice pick until the JAN/Phillips 12AT7 in V4 allowed for use of the treble and gain control. Normally had to dial them mostly out due to ice pick characteristics.

The other way to defeat the ice pick was speaker choice. Celestion Creme 90W Alnico did a really good job on filtering the higher frequencies and eliminated the ice pick on CH3. Did not favor CH1 or CH2 with that speaker. The Redback speaker was similar but had a better sound on CH1. I personally did not accept the Mark V90 in any favorable feelings. I tried to like it but just could not adapt.

For me the Roadster, Royal Atlantic, JP2C, Multi-watt Dual Rec, Triple Crown, and Badlander were the amps I desired. RA and BAD are my two favorites. JP2C falls in third. Since my experience with the Mark V90 did not live up to my expectations (tone or reliability) when compared to the Mark III that I used for over 24 years and the Mark IVb I ran for 12 years. Both were combos. I wanted a head for the 412 cab and got that in the Mark V. Not only did the amp overheat and burn up power tubes in less than 20 minutes if I was lucky. I had to find alternative tubes that would survive. Tung Sol 7851A lasted a good 6 months before loosing tone. Gold Lion KT77 ran a good 8 months at full power. The ideal tube I could not kill was the SED =C= 6L6GC. Anyhow, after all of that, I am not confident to get the Mark VII. Would I have the same headaches? Tube issues? Not sure. I thought I was the only one with the lemon. I still have it. Converted it from head to combo to keep the chassis cooler (found out the bias was messed up and corrected it, still not right but does not burn out Mesa tubes anymore). Made some hard mods to fix some of the ***** tones and abundance of higher order harmonics that lends to shot noise (ice pick). I believe some of this is related to the GEQ circuit. The V90 is not a door stop in the dining room. Have not powered it up since? about the time I gave up on the forums a few years ago.

You are the man, thank you...that is VERY helpful!!!! I am beginning to think some of what I heard was ear fatigue but actually put the Gold lion in V-4 andV-6 and am going to let them sit a bit.mine does not have the ice pick issue (I used to have a studio pre amp so I DO know what that sounds like, and it was even so with the cabs I use which are Marshall, so I know I have one of the revised amps). That sure sounds like the only thing that should even touch the second channel is V-2 (still I am thinking some of what I am experiencing might be some internal bleed when using at's, I know this fellow(Randall Smith) is all about sympathetic frequencies and stacking circuits to bend the way they act so maybe it is all just Mesa voodoo ********. He says chagrined, thanks for the reply. If you have any circuit mods you consider essential let me know...I opened mine up and replaced the four diodes considered problematic in the 12v line, but frankly I need to finish the repairs to the footswitch (The solder joints in mine were done HORRIBLY and they started to fail....I got the worst of them when I did the diodes but must have missed one cause it is chattering at me from time to time...I kick the footswitch and it stops so another bad joint!!!!) For all Mesa is so well talked about I have had massive QC issues and their Tech's were not the most helpful with the Mark V...other amps they have been better but the V they kind of piss on you :-(

 

[bandit2013]

Not sure what it is with the Mark V. Some have great success with the amp. Based on how this amp has many characteristic voices for each channel. The only two voices I really liked that were usable were on Ch2: Crunch and Mark I. For CH3 I was hooked on Extreme but with reduced treble and gain. The other modes were lame. Ch1, I get that tube sing issue where the tubes vibrate at the same frequency as the signal and that vibration may be louder than the sound through the speaker. That is tube related. Matters not if in combo form or head. I had that issue with the California Tweed for a short while. The fix was to replace the 6V6 tubes and the tube sing is no more. The CT is a dark amp in some respects but only when you use the desired speaker: Jensen Blackbird Alnico 100W. Yes, I said 100W. That is what came stock in my CT combo and had to get a matching 112 cab to go with it with the same speaker. The 100W Blackbird takes a long time to break in. I tried one in the Mark V90 combo. As for the CT with other speakers MC90, V30, EV, it is bright as hell. I finally got to the point with the CT where the treble is beginning to bloom. Throw on a flux drive and grid slammer and I have a Mark amp sound without ice pick blues. Badlander is another awesome amp right out of the box, one of my favorites as it does not have the sub harmonic blah that swamps the Rectifier amps (you need to drive them at gig level to get past the swamp and that can be too loud depending on your preference in volume). Royal Atlantic was another example of Mesa at its best but the trick with that amp is a few NOS preamp tubes for the Hi/lo preamp section along with some NOS power tubes. Nothing was better than that, until the Badlander came out. Triple Crown TC-100, for me it was a disappointment when it came to the multi-soak, no way near the RA100 performance level as the RA does give you more tube saturation you can hear, not with the TC100.

Sometimes it is hit or miss. Depends on what the designer (Mr. Smith) is reaching for. I think the Mark V90 was more focused on desires or needs of those who lost their hearing. Something about the 90W that irritates me. Don't get me wrong here, I am into the dark and sinister sounds of a beefy Mark amp. I want that grind I used to get with the Mark III but was a pain in the *** to dial in. Mark IVb was a slight improvement but not the pinnacle of excellence. It was close. Perhaps the Mark IVa would be the better option as it had the small footprint like a traditional mark amp. The IVb was the widebody and same width as the V90.

The footswitch is a cluster-F mess. Cable grounds are prone to issue. Channel selection is done based on a voltage level on one wire in reference to the ground plane. The chatter is a result of poor ground or bad connection for the channel signal. I took my FS apart and resoldered every solder joint. Even made a hard connection for grounding as that was an issue. The V90 FS setup is one of the worst I have encountered. At least the Roadster and MWDR never gave me any grief. Badlander is just a single button. Same bloody cast housing as was used with the Mark III amp. It just works. For me that is all that matters.

Considering the amps with footswitches with multi-functions that actually work without any issue are the ones that use a Midi micro-controller. JP2C, Triple Crown. Never had issue with those two platforms. That is one reason I am considering the Mark VII. The other reason is they ditched the GEQ based FX send. The VII has the GEQ placed in the traditional location, following the FX loop. No more odd-order harmonics that make for ice pick tones. Preamp tubes generally do not generate the odd-order harmonics, however it is more prone with BJT (PNP or NPN transistors which is what is used on the front end of the GEQ and back end that creates the FX send signal level). One of these days I may tear down the Mark V90 and go over every inch of the preamp board looking for weak solder joints. I believe what I may find will be something related to the GEQ section (most of it is on the main preamp board). I doubt it is related to diodes in my case but the year mine was built was in that range of diode issues. It is what it is, what it is not I have yet to discover. Mark V90, I have lost interest in it.

 

[user 83127]

Not sure what it is with the Mark V. Some have great success with the amp. Based on how this amp has many characteristic voices for each channel. The only two voices I really liked that were usable were on Ch2: Crunch and Mark I. For CH3 I was hooked on Extreme but with reduced treble and gain. The other modes were lame. Ch1, I get that tube sing issue where the tubes vibrate at the same frequency as the signal and that vibration may be louder than the sound through the speaker. That is tube related. Matters not if in combo form or head. I had that issue with the California Tweed for a short while. The fix was to replace the 6V6 tubes and the tube sing is no more. The CT is a dark amp in some respects but only when you use the desired speaker: Jensen Blackbird Alnico 100W. Yes, I said 100W. That is what came stock in my CT combo and had to get a matching 112 cab to go with it with the same speaker. The 100W Blackbird takes a long time to break in. I tried one in the Mark V90 combo. As for the CT with other speakers MC90, V30, EV, it is bright as hell. I finally got to the point with the CT where the treble is beginning to bloom. Throw on a flux drive and grid slammer and I have a Mark amp sound without ice pick blues. Badlander is another awesome amp right out of the box, one of my favorites as it does not have the sub harmonic blah that swamps the Rectifier amps (you need to drive them at gig level to get past the swamp and that can be too loud depending on your preference in volume). Royal Atlantic was another example of Mesa at its best but the trick with that amp is a few NOS preamp tubes for the Hi/lo preamp section along with some NOS power tubes. Nothing was better than that, until the Badlander came out. Triple Crown TC-100, for me it was a disappointment when it came to the multi-soak, no way near the RA100 performance level as the RA does give you more tube saturation you can hear, not with the TC100.

Sometimes it is hit or miss. Depends on what the designer (Mr. Smith) is reaching for. I think the Mark V90 was more focused on desires or needs of those who lost their hearing. Something about the 90W that irritates me. Don't get me wrong here, I am into the dark and sinister sounds of a beefy Mark amp. I want that grind I used to get with the Mark III but was a pain in the *** to dial in. Mark IVb was a slight improvement but not the pinnacle of excellence. It was close. Perhaps the Mark IVa would be the better option as it had the small footprint like a traditional mark amp. The IVb was the widebody and same width as the V90.

The footswitch is a cluster-F mess. Cable grounds are prone to issue. Channel selection is done based on a voltage level on one wire in reference to the ground plane. The chatter is a result of poor ground or bad connection for the channel signal. I took my FS apart and resoldered every solder joint. Even made a hard connection for grounding as that was an issue. The V90 FS setup is one of the worst I have encountered. At least the Roadster and MWDR never gave me any grief. Badlander is just a single button. Same bloody cast housing as was used with the Mark III amp. It just works. For me that is all that matters.

Considering the amps with footswitches with multi-functions that actually work without any issue are the ones that use a Midi micro-controller. JP2C, Triple Crown. Never had issue with those two platforms. That is one reason I am considering the Mark VII. The other reason is they ditched the GEQ based FX send. The VII has the GEQ placed in the traditional location, following the FX loop. No more odd-order harmonics that make for ice pick tones. Preamp tubes generally do not generate the odd-order harmonics, however it is more prone with BJT (PNP or NPN transistors which is what is used on the front end of the GEQ and back end that creates the FX send signal level). One of these days I may tear down the Mark V90 and go over every inch of the preamp board looking for weak solder joints. I believe what I may find will be something related to the GEQ section (most of it is on the main preamp board). I doubt it is related to diodes in my case but the year mine was built was in that range of diode issues. It is what it is, what it is not I have yet to discover. Mark V90, I have lost interest in it.

Yeah..kinda there as well...I have had this thing listed for a year...got close once (the guy wanted to ***** about 50 dollars and I was giving him a Road case...he saved his 50 dollars and got no road case, so whatever. I want to switch to Mark IV a. I have a Triaxis revision 2 recto mod non p[hat that is kinda Mehhh...it is ok...not as good as the Studio Pre (by listening to them the 33 mods sound like they would help but why bother when you can get a real mark somewhere)...the price I paid for it and what people are asking for them..there isnt a Mesa out there worth the money to buy them (they disappeared off the market...affordable ones....pre covid, about three years prior if I remember right). I would take 3 grand for the head and triaxis in a hot second (and THAT is overvalued frankly but less than the market shows right now) and cant get them gone, so for now I am stuck. I am NOT impressed with the Mark VII at ALL, it just looks like they doubled down on the WORST aspects of the V and imported new fresh hells from the badlander and JP2C (I am not taken with IR's at ALL)..I would rather see a return to the actual simulclass power sections of the early marks instead, but that is me. The V is just impossible to work on , you have to unsolder so many connections and remove the whole friggin board (they should have broken that thing into MANY subsections for ease of workmanship...but no,,,they even made it so bad THEY dont want to touch it!!!!

 

[bandit2013]

Well, that is what you get when you make a novelty amp. The V was one of the first to have some imaginary model voices. At least there are two voices on CH2 that sound OK.

Fresh hell from the Badlander, If you never played around with one, you may be missing out. I would not bother with the crap they are doing in the videos on youtube. There may be one that brings forth the good qualities of that amp. As for cab clone or the IR thing, was not the reason I bought it in the first place. For me it was all about the sound characteristics. I am not a djent player or need to have gobs of noise to get what I want from the amp. It grew on me very quickly it was worth while getting a second one. I did run the MWDR in the center for a short while, found it hard to part with the Royal Atlantic so it is now in use again. For me, the Badlander 100W meets my needs for what I do. Barely ever change channels as I can clean it up with the guitar volume. Same trick with the RA100. Then again, I still have the Roadster and MWDR if I need a darker sound and want to be loud. The BAD 100 and RA are both loud amps if you want them to be. Louder than the JP2C but that may change once I get a quad of STR415 tubes or something similar.

In some respects, the BAD is similar to the JP2C but with more aggressive appeal. On the flip side it is also similar to the Royal Atlantic in its fully useful dynamics. I was not sure it was the amp for me as I was looking to get another JP2C so I can run it in full stereo. The JP2C just seemed limited as it is basically a 2 channel amp, the third channel is not much different than the second, just a minor tweak on the gain. However, I do like the JP2C and still never listened to any of John Petrucci music. I did not get that for any artist following, I just wanted a Mark amp that did not suck. The trick with that amp is what you choose for the power tubes. Some of the current power tubes available are sort of lame. Out of what I have in my arsenal, it is either the 2BAD or 2RA100 that become my go to setup. The Roadster, MWDR, Mark V90, TC100, TC50, California Tweed, and JP2C usually remain cold. Once in a while I get them out but mostly enjoy the BAD + RA combination. I also have a Marshall Silver Jubilee 2555x 100W head and 412. Decent amp for what it is. The EVHiii5150EL34 100W was a mistake. Not bad but not all that great either. Sure, I also play a 7 string guitar, have two, one is standard scale and the other is a baritone. I am not fond of the extended scale guitars with the Roadster or MWDR, too much of a mud fest. The Bad, RA, TC, JP2C and even the Mark V sounded great with the extended range guitar and no need for any artificial boost using a front end pedal. Actually, the edge mode on the V90 with the 7string sounded good for a change. Still the Mark V is not for me. However, I have held onto it as a test bed of sorts. The amp may be a cluster-F to work on but it was where I started to tinker with the triode circuits as if I could make it sound better. A fool's errand but did learn a lot about what makes it tick. May still mess with it some more or just sell it off. The only time I ever liked the Mark V was after I converted it into a combo and tried out a Celestion Creme 90W Alnico. It did not last long as I found the bias was out of whack and the peak power on the power soak unit was pegging at 150W. That explained many things and why I kept red plating Mesa STR440 6L6 tubes. Before I destroyed the Celestion Creme 90W, I was messing around with a new Strymon pedal (BigSky) and a Strymon DIG. I may not be all that great at playing guitar, bass or drums. Was just an experiment of sorts. Was trying to blend some PinkFloyd with Deep Purple. There is no point in telling me I such at playing, I already know that fact.



I would agree that some of the older amps were much better in both gain characteristics and dynamics than what is currently being produced. Mark III is a kick-*** amp. Wish I never sold it. The Mark IV was just easier to use. I never played through the IVa model. The time I got back into playing again after the band broke up was around 2000, when the Mark IVb was out. Tried a Rectifier again, did not like it and never bought one until after 2013.

 

[user 83127]

Well, that is what you get when you make a novelty amp. The V was one of the first to have some imaginary model voices. At least there are two voices on CH2 that sound OK.

Fresh hell from the Badlander, If you never played around with one, you may be missing out. I would not bother with the crap they are doing in the videos on youtube. There may be one that brings forth the good qualities of that amp. As for cab clone or the IR thing, was not the reason I bought it in the first place. For me it was all about the sound characteristics. I am not a djent player or need to have gobs of noise to get what I want from the amp. It grew on me very quickly it was worth while getting a second one. I did run the MWDR in the center for a short while, found it hard to part with the Royal Atlantic so it is now in use again. For me, the Badlander 100W meets my needs for what I do. Barely ever change channels as I can clean it up with the guitar volume. Same trick with the RA100. Then again, I still have the Roadster and MWDR if I need a darker sound and want to be loud. The BAD 100 and RA are both loud amps if you want them to be. Louder than the JP2C but that may change once I get a quad of STR415 tubes or something similar.


View attachment 1505

In some respects, the BAD is similar to the JP2C but with more aggressive appeal. On the flip side it is also similar to the Royal Atlantic in its fully useful dynamics. I was not sure it was the amp for me as I was looking to get another JP2C so I can run it in full stereo. The JP2C just seemed limited as it is basically a 2 channel amp, the third channel is not much different than the second, just a minor tweak on the gain. However, I do like the JP2C and still never listened to any of John Petrucci music. I did not get that for any artist following, I just wanted a Mark amp that did not suck. The trick with that amp is what you choose for the power tubes. Some of the current power tubes available are sort of lame. Out of what I have in my arsenal, it is either the 2BAD or 2RA100 that become my go to setup. The Roadster, MWDR, Mark V90, TC100, TC50, California Tweed, and JP2C usually remain cold. Once in a while I get them out but mostly enjoy the BAD + RA combination. I also have a Marshall Silver Jubilee 2555x 100W head and 412. Decent amp for what it is. The EVHiii5150EL34 100W was a mistake. Not bad but not all that great either. Sure, I also play a 7 string guitar, have two, one is standard scale and the other is a baritone. I am not fond of the extended scale guitars with the Roadster or MWDR, too much of a mud fest. The Bad, RA, TC, JP2C and even the Mark V sounded great with the extended range guitar and no need for any artificial boost using a front end pedal. Actually, the edge mode on the V90 with the 7string sounded good for a change. Still the Mark V is not for me. However, I have held onto it as a test bed of sorts. The amp may be a cluster-F to work on but it was where I started to tinker with the triode circuits as if I could make it sound better. A fool's errand but did learn a lot about what makes it tick. May still mess with it some more or just sell it off. The only time I ever liked the Mark V was after I converted it into a combo and tried out a Celestion Creme 90W Alnico. It did not last long as I found the bias was out of whack and the peak power on the power soak unit was pegging at 150W. That explained many things and why I kept red plating Mesa STR440 6L6 tubes. Before I destroyed the Celestion Creme 90W, I was messing around with a new Strymon pedal (BigSky) and a Strymon DIG. I may not be all that great at playing guitar, bass or drums. Was just an experiment of sorts. Was trying to blend some PinkFloyd with Deep Purple. There is no point in telling me I such at playing, I already know that fact.



I would agree that some of the older amps were much better in both gain characteristics and dynamics than what is currently being produced. Mark III is a kick-*** amp. Wish I never sold it. The Mark IV was just easier to use. I never played through the IVa model. The time I got back into playing again after the band broke up was around 2000, when the Mark IVb was out. Tried a Rectifier again, did not like it and never bought one until after 2013.

Badlander, I will keep that in mind...that is what I have had in my head for a long while. A kick *** SINGLE channel that I can roll back, get clean for days, MASSIVE CRUNCH, then put a boost pedal in line to get Mark style leads or something like it,...if you know what I am talking about, the Mark amps (some of them) approach a kinda Bassman tone from time to time, that kind of Crunch that has just a tiny dip in the center (just enough so the honk aint there at all), then the rest is jsyu broad spectrum kick *** gain...THAT is my sound (oddly enough the Vamp-2 had one such sound if you ever payed that cheap, it was the alternate tweed setting...lol)...but I am 56 and older school than the doom crap of today. I Modded a TSL for myself (the amp was stellar, when the power was just so, and I didnt own a variac then, so I went down the online mod rabbit hole taking tips from forums and the Europa mod posted online, ALL WERE GARBAGE, but in doing one of the mods I went step by tiny step checking for effect all the way and HEARD SOMETHING in the steps that told me to mod ONE circuit (the "FAT") circuit, I took it down to about half the value of the installed circuit to mod the drive and what I got was less compressed than the original, but KILLER in all respects..that one is a keeper!!!...I even got lucky and managed to get the Classic Tone tranny 's and choke before they went kaput (WHAT A ******* SHAME)...although I am seriously beginning to question the whole LARGE TRANNY ethos....to me one of the characteristics of early Marks was compression and they used smaller tranny's than today..(yeah you get better bass from a larger tranny but since friggin when have Mesa's EVER been known for bass?!). I also have a tiny 6505 MH which is fun for experimentation with just rolling up gain to the limit 9it is so quiet that you can hit max and not blow your eardrums...it WAS THE amp that showed me how pointless it was to attempt to max tube amps in any way (they just fall apart at very loud levels,,,whats the point unless you ditch pre drive and just go power)....and I experimented with the TSL power attenuation and decided then that it killed too much tone (or rather changes it in weird ways and it wasnt for me)...real power and moving air if it needs that kind of volume (that also one reason why I choose Mesa type amps more often, lower volume playing is better on Mesa usually)...and I WAS a PETRUCCI fan, but more than that...I chose Mesa because I loved what I heard in the tone...NOT THE SONGS OF PETRUCCI...he just showed what the amp could do. That and I walked into a music store and played a Mark V and it NAILED THAT TONE....What the **** happened to that design and why the **** did they change it....my Mark sounds nothing like that at all(I think it was the ******* whiners about the ice pick highs...turn your friggin highs donw if it picks your ears...JEEZ)...HOW do I get my amp back to that...IS it even possible or did I just buy too late a model year...because ALL MARK V's DO NOT SOUND ALIKE!!!!

 

[bandit2013]

Nope, not all Mark V90s sound alike. Could it be component tolerances, change in parts or what? I had played a few others after I bought mine. Bummer, I feel I got a lemon. Power tubes also take part in the amp's characteristics. Just a change from one color code to the next can make that much of a difference. I have STR440 Greens in mine. It was what I had left to try out after I changed the bias to be normal as it was out of whack. Have not blown a power tube yet since the change but do not run the amp all that much, I get tired of it in 20 minutes if not a bit longer.

Can't say the same thing about the Royal Atlantic, Badlander 100, or the JP2C. I loose track of time when I run though any one of those. It is a good thing and a bad thing. Depends on when I decide to play. 4 AM, yep, I will be late for work. I am usually worn out when I get home so I am more a vegetable after work. Too damn tired to do anything. Probably because I get up at 4am to play the guitar. I blame it on the dog. He will be in my face if I do not get up before the alarm goes off an hour later.

I too am over the hill, 57. More old school Led Zeppelin, PinkFloyd, ACDC, Deep Purple, Scorpions, and I did some of the new progressive stuff too. Heck, even some the heavy sinister screaming death metal can be ok (depends on how irritating it gets or if they got it together and are making some cool music). I find I play more heavy metal stuff than other music when I am alone. In the group, we generally play more ACDC, ZZ Top, ***-Pistols, and some other stuff. Usually what the guitar player wants to mess up. I play drums in the group. I am getting better at it. At least the ACDC stuff is easy to pick up even if I do not know the song.

The Badlander 100W is BAD. Just a F-ing BAD amp. Avoid it at all costs. Just kidding. Try it out if you come across one. Not sure on the 50W or other mini formats. The BAD100 is kick ***. Clean is very similar to the JP2C clean but it has more juice to it, push the gain and well now, nice alternate vintage crunch. The Crunch Voice is almost Recto tone. Does not have the swamp (sub harmonic blah). It is perfect for many genera of music. Crush is mostly where it is at. Mark style compression and gain structure. It is close to the JP2C character with a moderate gain setting but you need to dial in the GEQ to thin out the mids on the JP2C or any Mark amp. No need for GEQ on the BAD, it just sounds great. It can bet more aggressive too if you wish. Full Dynamics on crunch or crush, I am hooked on the BAD in a bad way, so much I was willing to push the two Royal Atlantic RA100s into the storage area. I did have to get the head out as I found it blends better with the two BADS than the MWDR did. Call it a Fender Twin/Recto/Mark combination. Lends itself onto a modified Marshall 2204 but with more refinement. I guess I got hooked on the EL34 power tubes since the Royal Atlantic became my go to amp more so than the JP2C. Triple Crown was ok, fun amp but not on par with the RA or the BAD. I am lazy and would prefer to get lost in the tone without having to think about stepping on a footswitch to change channels. I use the guitar volume and roll it back to get my clean sound. Works quite well. Even thought the BAD runs EL34, It does not come off as a British Voiced amp. Not bad with the 6L6 tubes either. The other key feature on the BAD, the tone controls actually do something. MWDR, Roadster, and other models of the rectifiers prior, just do not have much of a responsive tone control matrix. It could be that it is due to the predefined tuning of the preamp (scooped). The BAD has a very common design to the MWDR with several exceptions; Mesa did away with the 39k ohm on the cold clipper, they went with 15kohms instead. Helps to eliminate the low end swamp and spice up the design. Yeah, it has the cold clipper circuit, with the high gain and dc coupled cathode follower driver for the tone stack just like the other Rectifier amps. However, it is a more usable platform for many playing techniques. If you are a palm muter like me, you do not have the mud to deal with like you do with the MWDR, Roadster and other Rectos. 7 String or dropped tunings, hell yeah. All day long if you want. Can't say the same about the other Rectifier amps. No need for OD or boost on the front end but does sound killer with that too. You have a choice, the blue pill or the red pill. Never found out what happens when you take both. I should ask Mesa for a paycheck.

Just for Sh!t$ and Gilggles, I pulled out the EVHiiis 5150 EL34 head. Noisy as heck but not all that bad. Ran it with the two BADS and was great. Did not beat the RA100 though. The RA was a better match to the BADs. Also lacks the same level of noise floor as the EVH amp. Thought about fixing that issue but will leave it as is. The noise gate was working ok. Had to force the dog outside as the SPL were on the high side. Perhaps the reason why I like the BAD, RA is that I do not need to run at gig level for the same quality of sound.

 

[bandit2013]

I generally gave up on responding to the Mark V forums. The V90 can be a rewarding experience for many. I just did not find it rewarding to continue to support the product. I do not hate the amp in general. I just do not like the one I have. Others will have a different opinion and I will respect that.

Also I should vacuum up the dog hair before taking pictures.

 

[mace]

Fellas…I would love it if y’all got a Mark VII and put it up against you V:90’s. Why? Becsuse it would save me a bit of coin to so the same!

Some of what you describe is what I’ve experienced on my late 2011 V:90 (single owner). I’m not as ‘on the outs’ with it as you guys but I must admit the draw of the VII is the simpler circuits and possibly getting closer to the tone in my head.

As far as to the CabClone IRs in the VII…as far as I know this has nothing to do with the tone going out of the speaker when it is disabled (not used). So, not sure what the complaint is with using much better XLR out technology compared with the passive original CabClone. It isn’t a negative for the VII by any means (other than it adds cost, I guess)

 

[user 83127]

I generally gave up on responding to the Mark V forums. The V90 can be a rewarding experience for many. I just did not find it rewarding to continue to support the product. I do not hate the amp in general. I just do not like the one I have. Others will have a different opinion and I will respect that.

Also I should vacuum up the dog hair before taking pictures.

Just wanted to touch base. As a result of our conversations I gave up on the V and switched my attention to my Triaxis. I know off topic. But I rolled in the original chinese and dropped some AT7's in the gain positions (V-2 and V-4) and have found sonic bliss for the moment (and for some reason the input gain never acted right on this one until I put the 12at7 in...now I get the notches at 8, 9 and 10), who knows how long it will last, this satisfaction, before I am forced to sell the V and find out what else....
To the guy that wanted input on the VII...find one and play it...to me...it sounds like a slightly modified V with the JP power amp scheme and no second eq...I would go JP2C of the choices now...at least you get 4 input gain selections (2 per high gain channel) and some power amp flexibility (dont you have some way to switch the negative feedback off on that one?). Badlander is looking good to at least try...although I must say I dont understand the reason that amp manufacturers handicap their lower wattage amps (I was thinking I would love a true 50 if they dont handicap the bass to encourage the sale of the 100 watter)..they should let the wattage sell the amp upgrade...instead they make the 50 watters sound slightly less than and the 20 watters mostly lose all bass and *** (and I have PLENTY of older 20 watt amps that say you dont lose bass because you use smaller tubes!!!).

 

[bandit2013]

I am one who wants the Mark VII Already have the JP2C and looking to add another Mark to my collection. Even got the stand for the head. I am not going to expect it to be better or worse. Just different. May have to get another cab though, sort of like running the two cabs with the JP2C. I believe it is the 4 ohm loading on the amp that makes the JP2C sound better. Ran the amp on the Recto 412, not bad, the two verts just sound better to me. I have this set up temporarily as I was trying out some STR448 tubes that came in the next day following the Vert 212 on the left.

As for different models of amps either being the same but only 50W vs 100W. There may be a perceived difference in the low end. My case is the TC100 vs the TC50. TC100 has ample low end where the TC50 is a bit more balanced. Not as deep sounding but still a fun amp. Same preamp circuit board too. Different transformers will sound different. Never played a Badlander 50W to compare to the Badlander 100. They could be on par with each other or may have some differences.

As for the dyna-watt amps, they are probably good in all respects. EL84 can carry the tone. Depends on the preamp and power section design and finally the speaker.

 

[user 83127]

I have not noticed any differences with the loading of the V. even tried different resistance ratings to see if i could get some kind of traction. (like running out of spec). I just put some el-34 in the V for ***** and giggles , but am playing the triaxis right now really anyways (you would know..can you use different tubes in the circuit (like mixing 6l6 with el34) if you stay in 90 watt mode...I know 10 watt mode is the killer and you also had other issues with yours...mine never had bias issues...I have not even blown through a set of el-34's yet and mostly stay off variac). I am talking about makers handicapping amps power sections deliberately...I have a peavey 6505 MH and it has the lousiest power section...devoid of ANY bass and I am convinced it is PEAVEY that did it so you would have to buy the big amp and NOT just get away with the little guy!!!!) EL84's can poush WAYY more bass than that...I know...they drive the HH scott and that is 40 watts of hi fi monster...it has ALLL the bass I could EVER want..same power tubes?!!!

 

[bandit2013]

I have not noticed any differences with the loading of the V. even tried different resistance ratings to see if i could get some kind of traction. (like running out of spec). I just put some el-34 in the V for ***** and giggles , but am playing the triaxis right now really anyways (you would know..can you use different tubes in the circuit (like mixing 6l6 with el34) if you stay in 90 watt mode...I know 10 watt mode is the killer and you also had other issues with yours...mine never had bias issues...I have not even blown through a set of el-34's yet and mostly stay off variac). I am talking about makers handicapping amps power sections deliberately...I have a peavey 6505 MH and it has the lousiest power section...devoid of ANY bass and I am convinced it is PEAVEY that did it so you would have to buy the big amp and NOT just get away with the little guy!!!!) EL84's can poush WAYY more bass than that...I know...they drive the HH scott and that is 40 watts of hi fi monster...it has ALLL the bass I could EVER want..same power tubes?!!!

The Mark V90 is not the same as the Mark IV or Mark III. There is purpose for the bias switch. Mark IV and Mark III never had such. Those were the only two Simul-class amps I am aware of being capable or running the integrated quad (6L6+EL34) where the EL34 are used in the class A sockets. Mark V not sure if it should be done. I would not recommend it. I do not believe the voltage drop on the Class A circuits will be enough to bias the EL34 properly. There may be someone who has done so. I have not tried that as I am not fond of amp repair.

 

[user 83127]

I am ...I just wish I could gain some insight about what to fix in this amp(to clear up the tone and fix the power section really!!!!) .That being said i went back to Phillips 12at7's in v-4 and v-6 and it has been awhile...I forgot how good it sounds to do that...so back to that I am. My Triaxis is populated with them also for now...back to the lower gain vintagey sound (I prefer the lower gain tones anyway). The EL34's sound like **** in the V and the 6L6 I had to mix pairs to get decent tones (I have the Short tung sols in the outer slots and the taller ones they put in Recto's in the inner slots)...I did some tube rolling of V-2 and V-3 before i did this and the funny thing I never noticed before....Roll V-2 and THE ONLY difference you get is to Mark 1 mode...Roll V-3 and you get changes to tweed mode on channel one....and also drastic changes to edge mode and Mark 1 mode....you have to roll v-4 to get any change to crunch mode and then you might as well roll v-6 and get the change to apply to the lead channel also!!!! WEIRD AMP and nothing makes sense or is logical....I think the insides are as twisted as the business logic of the company that made it (yes I am saying Mesa is doing ****** business and has been for decades...they could care less about the customers..ESPECIALLY now he sold to Gibson!!!!!!!)P