Mark V 90W combo speaker change

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One may think. It seems to do it with the Mesa tubes. Amp was working just fine with the old Beijing 1990 Mesa tubes. Since I was considering getting rid of the Mark V, did not want to leave in the good tubes so I put in Mesa stock tubes. I believe I have a bad tube, V4, V5 or V6. I just did not care. It was enough excuse for me to get it out of sight. I have spent too much time on tube rolling, messing around with the tone controls, changing speakers, and such that I ever did playing the guitar through it. It is one amp I cannot stand to listen too. It still has value so it will not hit the trash just yet. If I can get it to behave properly, I will sell it. For now, it will sit out of sight as I will want to try to do something with it. What a waste of money. Wish I never bought it. Trying not to go too negative on this, some people may cherish the Mark V90. Good for them. They can have mine.

As for motor-boating. The JP2C would do that with Tung Sol, Mullard , EHX, Svetlana. Medium plate design (12AX7, CV4004). Even the long plate Mullard was worse. I have not pinpointed which tube position causes this issue. It would not be hard to just roll one of the said instigators into each position to find out. It sounds just like a boat breaking over shallow waves. Not only does it oscillate, it grows exponentially louder and louder until you have to hit the standby switch. Amp works just fine with the stock tubes. Just does not behave well with the New Sensor stuff. Matters not of the tube is used and in good condition or brand new. Trying to think if it did this on clean as well. doubt it.
 
Everyone tells me to use a vertical 2x12 stack like this and I’m going to have to listen at some point. Since I have the combo and like the EVM I have in it maybe I can use a 1x12 oversized sealed v30 on top of the combo. Otherwise rhe Redback or the Swamp Thang or the BN-300S.

I want to say that even though I swapped it out of the Mark V, the BN-300S is just a beautiful sounding guitar speaker. It rolls off the top end and would normally be paired with something brighter.

I’ve been exploring different speaker options with different amps as well as listening to many speaker videos and have become more and more impressed by the V30s.

I have an interest in trying series wiring with the Mark V, using two dissimilar speakers. I will have to test this with a different amp first, but this is the idea. Take the V30. It has a crazy sound that comes from notches and and peaks in the impedance over different frequencies. The EVM Classic is wider range and almost flat. The speaker excursion is a function of current, which is identical for two series speakers. The impedance notches and peaks will be halved in amplitude and the two speakers will move air roughly in sync with one another. Mechanical resonances can still vary that. So that is the theory. I don’t have any experience with this. But since the Mark V can drive 4 or 8 ohms and the speakers I want to use come in 8 ohms, it would only work in a 4x12. So I’ll try with a 2x12 and a different amp to start with. If it works well then maybe the 4x12 can be set up as e.g. EVMs on the bottom and V30s on the top, with two pairs of the EVM Classic and V30 in series. What I would hope for is a moderated tone blending the EVM and V30 characteristics and a little bit of that wobbly phase shifting between the left and right side.


Glad to hear of the progress. In that cab it's two 16 ohm speakers wired in parallel.

In FWIW part 2... for my tastes the best cab match for the V has been this vert 2x12. It has a Mesa EVM in the closed bottom and a Mesa v30 in the open back top. Kinda used the old 90's Mesa vert cab approach. Got this old cab free from a buddy, it was pretty hideous :eek:decided to do a recover project. Originally it was a simple box, opened the top and added a separator. Tried a few different speakers in the top position ie: MC90, Eminence but finally settled with the v30 pairing. They are both 8 ohms wired in parallel. Sounds amazing also with the IIC+.

When I was up at Mesa talking to Mike B, he said they all felt the EVM was the right speaker for the Marks. He does all his testing with them. :)

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I don’t blame you for being pissed :)

We spent a lot of money on these amps and it took a lot of work for me to get mine working right. Your experience was even worse. Mesa screwed us since we both bought these things new. I didn’t know enough to realize the amp wasn’t working right. I’ll never buy one of their amps new again. Used, maybe.

I also don’t like the way they manufacture things. These amps are too difficult to work on. I love all the options but didn’t appreciate how hard it is to make an amp this complex work. I also didn’t realize that amps are like guitars and to make them sound their best always requires tuning work. Exponentially more work for more complex amps. Companies like Soldano/BAD and Bogner get their amps set up just right at the factory. But to keep them sounding good will still require tuning work!

But the amount of work needed and rhe fussinesss of the design is too much with the Mark V I got. When you think about the way you need to carefully select preamp tubes for the Mark V gain levels to avoid disastrous early clipping, it points to a design where the designers never fine tuned the resistors in the gain stages. I suspect they fixed some of this as engineering changes in years after we bought our amps. But it is actually irresponsible and lame what Mesa did with the amp I bought. I would have been happier with a used Peavey Windsor for $150 in 2013 and it would have been a better sounding amp out of the box, useful for almost any situation.

I recently bought a Jet City JCA-22 amp head for $250, and I like it less than my lovingly tuned Mark V, but only a little bit. I imagine the JCA-50 and JCA-100 amps are a step up. The SLO-30 might be The One.

Still, nothing else will ever do what my Mark V can do now. It is unique and I don’t think it even sounds like other Mark V amps. It really does have some of the Nirvana sound that originally attracted me to the amp, and it is so much more than that. I’m really happy with it now.



One may think. It seems to do it with the Mesa tubes. Amp was working just fine with the old Beijing 1990 Mesa tubes. Since I was considering getting rid of the Mark V, did not want to leave in the good tubes so I put in Mesa stock tubes. I believe I have a bad tube, V4, V5 or V6. I just did not care. It was enough excuse for me to get it out of sight. I have spent too much time on tube rolling, messing around with the tone controls, changing speakers, and such that I ever did playing the guitar through it. It is one amp I cannot stand to listen too. It still has value so it will not hit the trash just yet. If I can get it to behave properly, I will sell it. For now, it will sit out of sight as I will want to try to do something with it. What a waste of money. Wish I never bought it. Trying not to go too negative on this, some people may cherish the Mark V90. Good for them. They can have mine.

As for motor-boating. The JP2C would do that with Tung Sol, Mullard , EHX, Svetlana. Medium plate design (12AX7, CV4004). Even the long plate Mullard was worse. I have not pinpointed which tube position causes this issue. It would not be hard to just roll one of the said instigators into each position to find out. It sounds just like a boat breaking over shallow waves. Not only does it oscillate, it grows exponentially louder and louder until you have to hit the standby switch. Amp works just fine with the stock tubes. Just does not behave well with the New Sensor stuff. Matters not of the tube is used and in good condition or brand new. Trying to think if it did this on clean as well. doubt it.
 
Interesting update. I had been testing the amp with a great sounding solid mahogany Schecter guitar that has a Duncan JB humbucker in the bridge and a Bill Lawrence L500 at the neck. And that guitar with the EVM speaker is just wonderful.

I just tried my Strat which has an unusual mix of higher output passive single coil pickups, and for many purposes I really like the sound of this guitar. And it was great with the BN300-S in the Mark V. I’m finding the strat a lot less pleasing with the EVM though. I’m pretty sure I’ll figure out how I like to dial this guitar in with the new speaker and just do it automatically in the future. It was still a shock to hear how much the speaker change affected things.
 
Interesting update. I had been testing the amp with a great sounding solid mahogany Schecter guitar that has a Duncan JB humbucker in the bridge and a Bill Lawrence L500 at the neck. And that guitar with the EVM speaker is just wonderful.

I just tried my Strat which has an unusual mix of higher output passive single coil pickups, and for many purposes I really like the sound of this guitar. And it was great with the BN300-S in the Mark V. I’m finding the strat a lot less pleasing with the EVM though. I’m pretty sure I’ll figure out how I like to dial this guitar in with the new speaker and just do it automatically in the future. It was still a shock to hear how much the speaker change affected things.
:) certainly not surprised at all with that. Been my experience that finding a single amp/cab pairing to work great with every axe is pretty elusive. It can be a deep rabbit hole.
 
Many people have had glowing experiences like you describe with the Mark V 90W. That was far from my experience! Do you know roughly what year your amp was made?

My amp sounds just beautiful now. It took a lot of work though, and I wasn’t sure I would succeed until the end. I’ll summarize what I learned in this thread soon, once I feel the whole story is written.
This one has a handwritten date in silver paint pen by the power tubes of January 2012. Don't know what it's about... did they date them when manufactured, or was it denoting being serviced, or when tubes were installed? Dunno, but it's definitely at least 12 years old. It has the newer all-black footswitch. The first one I had (for 5 days) had the older footswitch with the aluminum edges. Had to return that one because the Tweed setting was broken and the reverb added a bad hum. I didn't get to compare them side-by-side, but they seem to sound the same.
I've been fighting with cheap amps for the past 3 years, so coming from those, the Mark V is amazing. I played a Mark VII combo in the local store and was like "THAT'S how I need my guitar to sound!" But $3500... I'd never heard my guitar sound so clear, bright, and detailed before, thru any amp I had used before. Well, the Marshall DSL20CR clean tone was close, but with that exaggerated British midrange I don't like, and the Ultra gain channel was muddy and fizzy. I've also had a Peavey Invective MH & ValveKing II 20 combo, Revv G20, Boss Katana 50, Marshall Valvestate 40V 8040, Line 6 Flextone III XL, and Carvin V3. The V3 is my favorite of all those, but they're all muddy, boxy, dark, and/or fizzy compared to the Mark V.
I am running a 10 band parametric EQ in the loop still, on top of the 5 band graphic in the amp. I've never met an amp that I could stand without extra EQ in the loop. But the Mark V sounds so much better without the extra EQ than the others... they sound so bad without EQ that they're unusable to me.
I am particular and have a very specific sound I need to hear, and the other amps were so dark I had to crank the treble and presence to get close to the sound I need, but that makes them harsh and abrasive. The Mark V just has this depth and detail, pristine clarity in the clean tone that none of my previous amps could compare to, even with the treble and presence maxed... they were still muddy, but also harsh with the treble up so high. And the channel 3 high gain has a midrange detail and presence without being excessive (quacky, *****, airy, boxy). And the low end is focused and has a punchy impact without being overly bassy. Mark I mode on channel 2 is really dark and bass-heavy and needs completely different EQ than channel 3 to make it usable. I have to use my Precision Drive AND Buxom Boost in front with their Tight knobs up to cut enough of the low end, and it took me almost 2 weeks but I'm finally getting a usable sound with the Mark I mode.
I need bright, but not harsh, and I'm getting that from the Mark V with the treble and presence just above noon, while on other amps they were at max and still muddy to me.
This is the first nice amp I've owned in the 26 years I've been playing, and maybe I'm easily impressed because of what I've had to compare it to, but this amp sounds exactly the way I want it to. I'm actually playing my guitar now, instead of just banging out riffs so I can turn knobs, trying to get a sound that my previous amps just couldn't do.
 
Don't take the negative comments to heart. Not all Mark V90s were lemons. I have played through a fair share of them that sounded way better than the one I have.

I am very pleased with the Roadster, MWDR, Mark VII, JP2C, Badlander, Royal Atlantic, Triple Crown, California Tweed, TT800 Bass amp and cabs, etc. The only amps I did not buy new were the two Royal Atlantic RA100's. I also owned a Mark III DRG combo for 24 years and it served me well over that time period. Mark IVB combo for 12 years without any issue. Would I ever buy another Mark V90? no.
 
It is awesome that you got a good one. The thing is that these amps have the potential to be some of the best you can get. They are stuffed full of amazing components and everything is high quality. None of us are completely sure why some of the amps are harder to get good sound out of, although personal theories abound. It makes me really happy to hear that you are having a good experience.

This one has a handwritten date in silver paint pen by the power tubes of January 2012. Don't know what it's about... did they date them when manufactured, or was it denoting being serviced, or when tubes were installed? Dunno, but it's definitely at least 12 years old. It has the newer all-black footswitch. The first one I had (for 5 days) had the older footswitch with the aluminum edges. Had to return that one because the Tweed setting was broken and the reverb added a bad hum. I didn't get to compare them side-by-side, but they seem to sound the same.
I've been fighting with cheap amps for the past 3 years, so coming from those, the Mark V is amazing. I played a Mark VII combo in the local store and was like "THAT'S how I need my guitar to sound!" But $3500... I'd never heard my guitar sound so clear, bright, and detailed before, thru any amp I had used before. Well, the Marshall DSL20CR clean tone was close, but with that exaggerated British midrange I don't like, and the Ultra gain channel was muddy and fizzy. I've also had a Peavey Invective MH & ValveKing II 20 combo, Revv G20, Boss Katana 50, Marshall Valvestate 40V 8040, Line 6 Flextone III XL, and Carvin V3. The V3 is my favorite of all those, but they're all muddy, boxy, dark, and/or fizzy compared to the Mark V.
I am running a 10 band parametric EQ in the loop still, on top of the 5 band graphic in the amp. I've never met an amp that I could stand without extra EQ in the loop. But the Mark V sounds so much better without the extra EQ than the others... they sound so bad without EQ that they're unusable to me.
I am particular and have a very specific sound I need to hear, and the other amps were so dark I had to crank the treble and presence to get close to the sound I need, but that makes them harsh and abrasive. The Mark V just has this depth and detail, pristine clarity in the clean tone that none of my previous amps could compare to, even with the treble and presence maxed... they were still muddy, but also harsh with the treble up so high. And the channel 3 high gain has a midrange detail and presence without being excessive (quacky, *****, airy, boxy). And the low end is focused and has a punchy impact without being overly bassy. Mark I mode on channel 2 is really dark and bass-heavy and needs completely different EQ than channel 3 to make it usable. I have to use my Precision Drive AND Buxom Boost in front with their Tight knobs up to cut enough of the low end, and it took me almost 2 weeks but I'm finally getting a usable sound with the Mark I mode.
I need bright, but not harsh, and I'm getting that from the Mark V with the treble and presence just above noon, while on other amps they were at max and still muddy to me.
This is the first nice amp I've owned in the 26 years I've been playing, and maybe I'm easily impressed because of what I've had to compare it to, but this amp sounds exactly the way I want it to. I'm actually playing my guitar now, instead of just banging out riffs so I can turn knobs, trying to get a sound that my previous amps just couldn't do.
 
Speaker change update. I changed speakers in my Marshall 1960A cab. Now 2 EVM 12L speakers in the lower positions, two Celestion G12H-150 Redbacks in the upper slant positions. Besides not wanting the cab to be topheavy I also thought the darker Redbacks could use the upper boost and bass cut the slant positions offer.

I have series in the vertical positions so I can run the cab stereo as two 16 ohm stacks or series parallel for 8 ohms. I like that the two different speaker types are in series in each case, since in theory it should even out the differences a bit. I also want the speakers to interact as pairs for the little phase shifts. So no X pattern; like pairs sit beside each other in like enclosures.

I recently acquired a 100W Royal Atlantic head for $1000 and I felt like this was a really good deal. I’m playing hot guitars and even without a boost I can get as much gain as I ever need from the amp. It runs 4x EL34s. So I’ve been using that with the cab but will run the Mark V through it too. The RA was the endpoint of a search for a solid 100W head that could make all the Marshall sounds. There were lots of good alternatives but I ended up feeling like there was not much difference if I were to get a very expensive Bogner or Soldano. The RA has great magnetics which is what I think you are really paying for with e.g. a SLO 100. That and meticulous setup, which I’m willing to take on. I read that at one point Bogner was spending 7-8 hours in their shop in selecting the preamp and amp tubes they put in their amps. And that is wonderful, but then what do you do when it is time for new tubes?

Anyway so far it sounds unearthly. I am in guitar heaven.

I owe a lot to people here for helping to guide me to good choices with some of this stuff. Bandit suggested the RA100 or Badlander at one point and also told me about his success with Redbacks. This approach is also not very different from the EVM/Swamp Thang success story.
 
Oh yeah, the RA100. If you get tired of the more forward sound from the amp, Try to find a quad of the SED =C= EL34. Mesa STR442. I believe Ness Tone has some of the STR442 as I bought a quad a few months ago. I have been running the SED =C= EL34 for several years, almost 10 years. That is a huge difference with those tubes compared to the STR447 or STR450.

The trick to tighten up the hi gain channel is with a Mullard CV4004 in V1 and a Mullard 12AX7 in V2. The Hi/lo channels are isolated from the clean and V1, V2 will have no effect on the clean channel. So far the best V1 tube I have used in this amp is the RFT 12AX7/ECC83 and an Ei CV492 in V2 (similar to the NOS Mullard 12AX7 or the reissue version).
 
I recently acquired a 100W Royal Atlantic head for $1000 and I felt like this was a really good deal.
Yes that is a good deal, no brainer TBH. Congrats. There are a few good choices for that Brit sound in the Mesa camp, the RA is certainly worthwhile if you can find one. @bandit2013 had stoked the RA GAS but eventually went for a BAD, mostly cause I stumbled across a no brainer deal. Can't go wrong with either. It's a nice contrast to the V for sure.

So I’ve been using that with the cab but will run the Mark V through it too.
Interesting to hear how that goes. Personally I dig the V with the EVMs
 
I will try some of this tube rolling stuff for the RA. Even as I received it I almost couldn’t be happier with this amp. It has glorious Marshall sounds. Makes me realize that the Mark V was not so much the wrong amp for me as it should have been a second priority after something like this. Well, there is one thing I want to understand better. I have the Bassman and the 50W Plexi and the 80W Bogner Shiva and they all have an enormous percussive thing going on. The Shiva perhaps most of all can feel like a shot when you hit it. And the RA can be a little boomy so I cut the bass some usually, but instead of that bang it has the midrange growl and all the singing sounds that sustain beautifully. The percussiveness of those other amps has got to be an RC time constant on some of the power rails, and I don’t know how it works yet. I’d like to have a knob for it.

But… the Mark V is wonderful and apocalyptic through the new cab. I don’t know how to describe it, but it is really good. So very different from the RA. Also, the EL34s are still in it and I found the 4x12 a lot more ear friendly with the big cab. I need to switch it back to the 5881/6L6GC mix where it sounds its best and try again, but this is a great cab for many purposes. It is smooth, not gritty though. The distortion sounds are all there, just articulated and detailed. It was a shock to hear the RA through G12T-75 speakers and then the Redback/EVM mix. And the same with the Mark V. The 300W 12L in the Mark V combo is already huge, so I’ll go back and forth a little and try to make a coherent comparison there.
 
The V definitely has a core voicing that is unique and pretty different then an RA or a Stiletto. But I think they complement each other well.
Yes. It makes me appreciate the Mark V more actually to hear these side by side. It will probably take some time to understand what is going on that makes it so different.
 
Most of the Mesa amps have a hint of power sag when driving the amp harder. Even the Triple Crown which can be dry sounding (uses op-amps to compensate the tube preamp parts) will have some sag. So, it does not feel like dropping a pallet of bricks of the top of the building when slamming the power section with a monster chord, that percussive punch will get quelled with a bit of power sag. There is also a mutual coupling with the bias circuit that changes when the power shifts. That was mentioned in one of the Mesa commentary videos or interviews. Mesa has preserved the characteristics that made the older amps sound good. Sure, it is a long shot idea. Not stating any fact here, just a crap shoot of what may be possible. It could be the reactance and mutual coupling you get with the speaker driver and the OT. That becomes a fine art in design and selecting the characteristics of transformers and such.

I found the Mark V90 was a bit far removed from the older designs considering the overall tone, even the Mark IVB was a bit of a stretch from the traditional sound. Not saying the amp is bad, it is just tuned differently than the IIC+ and III. JP2C and the Mark VII sort of returned than sound characteristic in a way they dropped the box like tuning. The IV mode on the Mark VII is probably the best I have heard yet. I no longer have the IVB to compare it with. The EV was OK, but made the tuned preamp sound more boxy. EV has more of a flat response curve and a higher top end before rolling off. It can be unforgiving if your amp has ice pick tendencies like the Mark V90 I have been struggling with. I found the same characteristic with the EV speaker and the Mark IVB combo. OK but not a good fit. JP2C, Mark VII, IIC+, III and not quite sure on the IVA were better served with the EV speaker. Those amps still sound killer through the V30 and other 12 inch varieties. What actually worked better with the Mark V90 was the Celestion Cream Back G12H-75. After hearing that in a traditional 412 cab (non-mesa) I had cursed myself for selling the head shell for the Mark V90. It seemed like a better fit. I thought the Celestion Creme Alnico 90W speaker sounded the best for CH3 as my mark V is the ice pick model. That was sweet music to my ears. Too much top end roll-off for most amps though. My mark V90 finally died and I am going to leave it that way for a while until I want to get back into self-torture. I have this idea I can fix it. Just need to find what is wrong with it and why it is such of an ice pick. I believe it is with the GEQ circuit, yeah it works fine, it is not the differential part of the circuit. I think it is more to do with the frist transistor stage involving Q1. Sure you can bypass the GEQ but it does not bypass the transistor circuits, it only pushes a high impedance on the differential circuit so it is not influencing the tone. If the GEQ was after the FX loop I would know if the preamp was the root cause but nope, it is the GEQ that is used for the FX loop send signal.
 
I will respond more later but there ought to be a way to test that. I’m quite sure you can fix your amp. Your help and thoughts allowed me to eventually make my MarkV good and continue to be invaluable. Thank you!

Very briefly, I saw the GEQ on my amp contributing to the spikiness. It was not the main driver for me, but might be for you.

The method that I used most successfully was square wave and sine wave signals through the input and effects loop, just as I saw you do. Then monitor at the effects loop or slave with the scope. You showed me that the apparent overshoots eg on the rising and falling edges of a square wave test signal are not ringing per se.

Something I haven’t tried but maybe would be good in your case would be to temporarily bypass the presence circuit with a fixed resistor and make sure you can reproduce the spikiness. We don’t have the identical problems but anyway there are commonalities:
  • Hot bias (power stage gain factor) makes things worse
  • Extreme presence boost
  • For me, much of the boost was created in the power stage but not alll
  • The problem is not just overshoot and it is also not just equalization.
Something I didn’t do was use a sweep generator and FFT to get the frequency response. The tools I used at the time were a little crude and I could have been more systematic. But it is down to a reasoning problem if we recheck the evidence.

Here is something to consider. If the problem does not involve the presence feedback or anyway the power stage then how do we see it get relatively worse with power stage gain? Well, high frequencies above where the speaker cannot comply will appear disproportionately in the feedback. So problem is either related to places where the speaker can’t comply or it is not. There could be non ideal behavior in that regime. Equalization errors upstream in the preamp get us into the frequency band where the feedback circuit misbehaves. Alternatively there is just an unwanted resonance that increases the feedback impedance at certain frequencies. But still it comes down to equalization errors exciting the problem. Or it is not that at all. But careful testing with a sweep generator should crack this open. And if the issue is only in the GEQ it should that too. The problem for me is how easy it is to misobserve. I have to look over and over again.
 
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By the way I said that thing about the RA not being as punchy as related amps. But I saw yesterday that the clean channel is very percussive. I feel the percussiveness is created by the sag. You pointed out that the gain channel do not cascade from the clean. That should make it easier to understand. I love that there is not a feedback cut for presence :)
 
By the way I said that thing about the RA not being as punchy as related amps. But I saw yesterday that the clean channel is very percussive. I feel the percussiveness is created by the sag. You pointed out that the gain channel do not cascade from the clean. That should make it easier to understand. I love that there is not a feedback cut for presence :)
 
If the GEQ was after the FX loop I would know if the preamp was the root cause but nope, it is the GEQ that is used for the FX loop send signal.
Frankly really never understood the thinking of placing the GEQ there. I'm sure there was some reasoning, but can't be convinced it's a good one. Fortunately I've been able to work around it, but that along with the line level of the loop took time and some heavy tweaking of my patches in 4CM, especially the time based ones in the loop in comparison to the other amps.
 
Punchy sound is having a lack of power sag. More of an urgent response than laid back. There is so much related to the power transformer and its circuits along with the response of the output transformer and such. Sort of like running a Roadster at full power using the silicon diodes vrs running the tube rectifier. The Rectifier tube has a slower response to recover than the Silicon diodes. Also, there is a slight drop in plate voltage when using the tube rectifier vs the diode. Couple that with the PT and OT to a desired effect. I am just using the Roadster as an example. I can hear that sag in all of the Mesa amps, just different a different degree from one amp to the other (based on the model).

The RA100 will appear to be more forward than the Mark amps. That amp will give you the note before you even strike the string. Not really but that is the impression one gets. It seems it has more to due with the power tubes used in the RA. I have explored a variety of EL34 tubes in that amp and settled on the SED =C=EL34 as they put a smile on my face. Those tubes aided to remove that immediate forward response just enough to sound really good. I could get used to the STR447 if I have too.

Considering the STR447 EL34. I am surprised that the Badlander and the Triple Crown sound really good with those tubes. Much higher plate voltage than the RA100.

It is all good stuff. As for the Mark V90, I will get it working again when I am ready to unload it. It works, just has a preamp tube issue and I decided to give up spending more time on it.
 

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