NAD: Mesa Boogie Mark VII head. WOW

[SonVolt]

Does it finally rival a real Mark IV's lead channel?

 

[kmanick]

Does it finally rival a real Mark IV's lead channel?

I'd love to know this as well

 

[bandit2013]

Kudos to the RFT 12AX7 ECC83 tubes. I use them in my two RA100s. Tightens up the low end on the high gain channel. No flub. Compatible with 7 string guitar. The RA100 is still my favorite amp to date. Also got me hooked on running in stereo.

As for the Mark IV. I no longer have the Mark IVB, mine was a combo so that sort of killed the excitement.

I would think the Mark VII is much on par with the IVA or IVA/B or the IVB. As with any amp I am sure there are differences. The Mark VII is almost a perfect match for the JP2C. I can get both very aggressive sounding.

High praise for the EVM12L speaker. One of the Best paper cones glued to an aluminum frame I have yet to hear with the Mark VII or the JP2C. Brings me back to the Mark III days. Too bad those are not available in a 16 ohm format as I would have loaded up my V212 cabs with them.

 

[SonVolt]

The secret to a Mark IV combo was to order a new Mark IV Headshell from Mesa like I did.

 

[bandit2013]

Yeah, I had the head shell from the Mark V I could have used it with the Mark IVB chassis as it did fit. the Mark V90 chassis did not fit into the Mark IVB combo shell. I had the wide body version of the IVB. It was tuned differently than the Mark III as that amp did not sound good with the EV speaker. Tried that and well, not a good fit. Mark VII or JP2C, excellent amps to run with the EVM12L Classic or Black Label speaker.

 

[bandit2013]

It has been a long time since I had a Mark IVB. I had a combo and the MC-90 held the amp back too much. Needless to say, the Mark VII in IV mode sounds really good. It compares very much to the CH3 of the JP2C or even the Badlander on Crush mode. Sound quality and tone density will be different between the amps. Even the IIC+ mode nails that sound. Sure, the Mark VII as well as the JP2C do not have the additional gain controls like a IIC+ or IVB. The older amps had two gain controls (sometimes it was labeled as volume or lead drive). The mark VII and JP2C have that early gain control in a fixed format. However, I am curious to figure out what the dual pot volume control works. It is obvious that one of the dual pots is the output level after the FX loop. But the other one? Is it a send level control or is it that other circuit they omitted in the JP2C? Would be nice to see a schematic to get a better understanding of how the amp works. I do understand the basics based on the tube task chart and where the tone stack sits in the different modes. I did ask Mesa about that and they did confirm the tone stack follows the lead drive circuit in the crunch and VII modes but is positioned in the traditional location for the other modes. Relay magic.

I would not doubt there are several videos out there that may compare the Mark VII to other amps like the IIC+, Mark III, and perhaps the Mark IV. Not to mention the VII vs the JP2C. The Mark VII is a very useful instrument. I would say it is on par with the Mesa amps from the early days, different but close enough to enjoy it.

Now that I have two of them. I can say this, they are practically identical. Not much of a difference if they are dialed in the same way. that would be a good platform for the stereo effects. I was struggling with the Mark VII and JP2C since the send levels were more dominant from the Mark VII and that seemed to burden the stereo effect that copied signals from one channel and reflected it onto the other. Strymon BigSky is my reference. the Strymon Timeline does not do that. Boss DD-200 will also reflect sound from both channels on the other, depends on the mode.

 

[SonVolt]

IMO, Stereo is a lot easier (and sounds better) if you just go full W/D/W and add in a stereo power amp instead of slaving another tube amp. I wish I would have picked up a Matrix GT800FX years ago.

 

[playingitloud]

I have a Mark IVB and the Mark IV on the Mark VII is different.

I would say the Mark VII sounds like a modern/tighter/thinner version of the Channel 3 from the Mark IV.

I was going to sell my Mark IVB until I compared them then I had decided to keep my Mark IVB since it does have it's own thing going on there.

I had an opportunity to trade a Mark VII for a KSR Colossus on Wednesday so I'll know tomorrow when it arrives if that was a good decision (fingers crossed).

The JP-2C just sounds a lot thicker to me than the Mark VII and I can see myself playing the JP-2C more since I really was having the Mark VII just set to a Clean Channel, Crunch Channel, and a MKIV or IIC Channel.

The Mark VII is a great amp with a lot to offer and I am glad that I had a chance to own the amp with no regrets.

 

[bandit2013]

Just to point this out, going stereo may be easier with a power amp pushing the speakers for left and right channels and using the center or amp that derives the main sound in the middle, sure that would work out fine.

I had done W/D/W thing with three amps, as I have them and do not have a stereo power amp like a Mesa 2:90 or the like. Depends on the amp and what you have for outputs. Sure you can slave out to a power amp with no return for a W/X/W or use a signal splitter to retain the return and make use of the amp in the middle for that W/D/W effect. Just keep in mind what is in the middle will work with you or against you if it is in phase or out of phase. I do not want to try to find a used 2:90 and hope it still works, Nothing wrong with that though. May even cost less to run a stereo power amp than using separate amps. If Mesa still manufactured them, I probably would consider that. All you need is a tube preamp or rack mount amp to go with it.

I found it more difficult to work with three amps vs two. Not because of the added complexity of dialing in each amp, more so the combined effect of the three amps and where the sound is perceived to be coming from. (the center). With 2 amps you get that convergence of sound between the cabinets and you feel the sound is coming from the center of the two. Adding in a third amp it will enhance or take away from that central point. Once it is all dialed in, and you mute the outer two amps and hear what the center one is doing, barely anything. How is this contributing? It sounds terrible. It gets more interesting with 4 amps. Instead of one stereo channel you get two. Now you can drive all the amps harder since the point of convergence of sound is coming from three locations and not just one. It gets more interesting if the effects are different in each stereo channel. Make it more complex with a double tracker effect feeding into the two signal splitters you used to isolate the 4 amps inputs. That is my basic rig, a Strymon Deco feeding into two Mesa Switch tracks, each switch track has a Badlander and Mark VII connected to it. The Bads share the one stereo effect channel (Strymon BigSky, it may also include a stereo delay like the Boss DD-200). the Mark VII amps will run through a Strymon BigSky and Timeline. Setting up the effects so there is a slight delay on the outer two amps relative to the inner pair you get a wider field, and it makes the room sound much larger than it is. Since the Mark VII and Badlander have similar power modes, Full/Half/Quarter you get good use of that depending on time of day or night you decide to make noise. Then again, my rig can be changed at any time, may roll out the RA100 or the TC amps, Sometimes I want to run the Roadster or MWDR. If I had the room, I would keep out the JP2C and use the 410 cabs with that as a fifth amp. Tempted to try it and see what happens. Easier said than done but I probably could manage the signal routing and make it work.

Running two amps of the same caliber, best to use stereo effects to take advantage of that. Yes, you do use the FX loop of each amp and send it to a stere effect unit. There should be no ground loop issues with that either. Match amps or not it will still work. If they are the same the loops will also be at the same level, if they are different amps, the loops may not be at the same level and it throws things off a bit.

Without effects, running two of the same amp is much like running only one amp with two cabinets if that amp can push them. I have run two 412 cabs with the RA100 and that provided that pseudo ambience effect. Then there is the mix of different amps which does have its merits. Many artists will do this, Gretta Van Fleet is one example. They may all be Marshalls but they are not the same.

 

[bandit2013]

I have a Mark IVB and the Mark IV on the Mark VII is different.

I would say the Mark VII sounds like a modern/tighter/thinner version of the Channel 3 from the Mark IV.

I was going to sell my Mark IVB until I compared them then I had decided to keep my Mark IVB since it does have it's own thing going on there.

I had an opportunity to trade a Mark VII for a KSR Colossus on Wednesday so I'll know tomorrow when it arrives if that was a good decision (fingers crossed).

The JP-2C just sounds a lot thicker to me than the Mark VII and I can see myself playing the JP-2C more since I really was having the Mark VII just set to a Clean Channel, Crunch Channel, and a MKIV or IIC Channel.

The Mark VII is a great amp with a lot to offer and I am glad that I had a chance to own the amp with no regrets.

How would you say the JP2C compares to the Mark IV? Just out of curiosity.

I had been eyeing up the KSR amps for some time. Also looked at Driftwood and Mezzabarba. Then there was Dynamo Amplification and so on. Just never really got that interested in making a commitment. At the time, the JP2C was more affordable. Not now, but when I bought it new back in 2016 it was well under the asking price for the other amps. Also had that sound I was seeking. The Mark VII is different, similar tone and some of the Characteristic, just not as detailed with the same level of tone density. Most of that I believe is the difference between the Class A/B vs Simul-Class. I did not get the level of satisfaction from my Mark IVB combo when using a 412 cab with it. It was a decent amp but a bit boxy sounding. The Mark V was more of an ice pick and more of a boxy tone. I felt that both were a far deviation from the Mark III that I had. To me that was ideal. Should have held onto it. Just my opinion, we all have our favorites. The JP2C had that sound I missed that I could not get from the Mark IVB or the Mark V90. To be honest, I could never get that sound with the settings used on most of the videos people have shared. Only one time did the Mark IVB sound as epic after mixing a pair of SED =C=6L6GC tubes and TAD 6L6GC-STR tubes. I guess in respect to the Mark IVB amps, it made a huge difference with the Power tubes used. Are you using all 6L6 tubes or a blend of EL34/6L6? At least with the Mark IVB you can do that. Not possible with the Mark V90 or the Mark VII. It is either one or the other but not both at the same time.

Yeah, the SED =C= 6L6GC tubes sound really good in the Mark VII. I only tried them for like 30 minutes or so. Wonder what a pair of TAD red-base STR448 would sound like with a pair of SED=C= STR454 tubes. I will have to try that one of these days. For now, the STR445 yellows work well.

Good luck with the KSR. Interesting amp.

 

[endofall]

I have a Mark IVB and the Mark IV on the Mark VII is different.

I would say the Mark VII sounds like a modern/tighter/thinner version of the Channel 3 from the Mark IV.

I was going to sell my Mark IVB until I compared them then I had decided to keep my Mark IVB since it does have it's own thing going on there.

I had an opportunity to trade a Mark VII for a KSR Colossus on Wednesday so I'll know tomorrow when it arrives if that was a good decision (fingers crossed).

The JP-2C just sounds a lot thicker to me than the Mark VII and I can see myself playing the JP-2C more since I really was having the Mark VII just set to a Clean Channel, Crunch Channel, and a MKIV or IIC Channel.

The Mark VII is a great amp with a lot to offer and I am glad that I had a chance to own the amp with no regrets.

I've been curious about how much bigger/punchier the JP2C is. To me my mark vii sounds as big and punches as hard as my multiwatt triple rectifier and as hard as my old mark III red strip with the ++ mod. It absolutely hits harder than I could ever make my mark v but I'm always so curious about the JP2c and the mark IV specifically the revision A. With all that being said it has been making me curious about stuff like kt88's in the mark vii

 

[bandit2013]

JP2C punches harder than the Mark VII. It becomes more evident with a speaker cab change. Say the Boogie 410 cab. JP2C was epic, the Mark VII sort of not compatible with that cab. The JP2C has a bit of an advantage with the presence shifting capabilities with the pull knobs. You almost have to run the 410 as bright as you can since it will be mostly low end and midrange. The upper mids are not as abundant with that cabinet.

Then move on to a 410 cab with the V30, JP2C is a power house and has a characteristic grind you cannot get from Simul-Class or at least in the ilk of the Mark VII. Mark V90 is weak sauce in comparison.

How would you say the Mark III ++ compares to the Mark VII? That would be interesting to read your comments on that subject.

The MWDR has more sub harmonic low end compared to the JP2C, at the time, both amps had the STR440 grey coded tubes. The big difference was the JP2C works really good with a 7 string (not using the shred mode either) but with the MWDR it was just mud-fest.

Considering the Mark IV, Mark III and IIC amps, you get one or two more controls for addressing the gain structure that you do not get with the Mark V, Mark VII and JP2C.

However, when comparing the Mark VII to the JP2C, they are different even if they sound much alike. The grinders in the Mark VII are the crunch, VII, IIC and IV modes. IIB is more of a medium grind but decent enough if you figure out that mode. The JP2C has 4 grind modes too. Two of which are hidden features but are contained in the gain knob pull switch. Then there are two presence modes with the JP2C as they presence knobs have pull switches as well. Leave the sets of pull controls pushed in, CH2 is very similar to the IIC mode of the Mark VII and CH3 is much like the IV mode of the Mark VII. Where they differ is how the tone controls effect the gain structure. The midrange control on the JP2C will increase the gain level. I tried doing the same with the Mark VII and I did not have the same effect. The tone controls behave differently as well as the two GEQ circuits. I would not hesitate to get a second JP2V but the current asking price keeps going up. Sure after getting the second Mark VII, I found a deal on one of the Limited Edition JP2C that was much less than the investment. That one was reachable too, just a day drive and I would be there. It was tempting. If it is still available, I may get it.

 

[bandit2013]

Oh well, that deal on the JP2C limited edition has ended, sold. I just saw that a day or so ago. poof. When the good deals are out, they go quick.

Today I was going to get all of the FX units connected and do a rundown of the two amps together but got stuck doing something else. Had a pinging tube that was on the edge of going microphonic. I was just going to roll in one tube to see if I can find it, first one I chose to swap was it. V1. So I would up playing for 2 hours today with both amps. Switching between one or the other or running them together. At first I thought CH2 was much louder than the other two. Nope, it was a mind game after reading about the one Mark VII that was returned and someone else got it. All good.

I would have to say that running two sounds really good. One footswitch to control both amps makes it so much easier. Sort of forgot about my agenda with the FX loops. I will get to that sooner than later.

I cannot say which I like better, Mark VII or the JP2C. They are both great amps. I like the Badlander 100 just as much. I just wish they did not cost as much as they do.

 

[little-b]

Great overviews!
I'm getting ready to buy a vii and/ or a jp2c too.For all you out there that own or owned both; how are the " in between " sounds of each? Ie: mid or lower gain, chimey,sparkly,jangly tones?
I'm a shredder head all day long and i love the high gain tones of my iic+, & coli"s all day long ,but as usually is the case,every demo i see is for the crazy high gain metal chugga stuff.Surely there's got to be some real nice low gain tones in those amps? I would especially think on the vii- 2b mode?
Anyone stumble across any nice chimey low gain tones on these?

 

[playingitloud]

How would you say the JP2C compares to the Mark IV? Just out of curiosity.

I had been eyeing up the KSR amps for some time. Also looked at Driftwood and Mezzabarba. Then there was Dynamo Amplification and so on. Just never really got that interested in making a commitment. At the time, the JP2C was more affordable. Not now, but when I bought it new back in 2016 it was well under the asking price for the other amps. Also had that sound I was seeking. The Mark VII is different, similar tone and some of the Characteristic, just not as detailed with the same level of tone density. Most of that I believe is the difference between the Class A/B vs Simul-Class. I did not get the level of satisfaction from my Mark IVB combo when using a 412 cab with it. It was a decent amp but a bit boxy sounding. The Mark V was more of an ice pick and more of a boxy tone. I felt that both were a far deviation from the Mark III that I had. To me that was ideal. Should have held onto it. Just my opinion, we all have our favorites. The JP2C had that sound I missed that I could not get from the Mark IVB or the Mark V90. To be honest, I could never get that sound with the settings used on most of the videos people have shared. Only one time did the Mark IVB sound as epic after mixing a pair of SED =C=6L6GC tubes and TAD 6L6GC-STR tubes. I guess in respect to the Mark IVB amps, it made a huge difference with the Power tubes used. Are you using all 6L6 tubes or a blend of EL34/6L6? At least with the Mark IVB you can do that. Not possible with the Mark V90 or the Mark VII. It is either one or the other but not both at the same time.

Yeah, the SED =C= 6L6GC tubes sound really good in the Mark VII. I only tried them for like 30 minutes or so. Wonder what a pair of TAD red-base STR448 would sound like with a pair of SED=C= STR454 tubes. I will have to try that one of these days. For now, the STR445 yellows work well.

Good luck with the KSR. Interesting amp.

I think the JP-2C sounds better than the MKIV where the JP-2C is really easy to dial in a great sound right away.

However, the MKIV is the best MKIV out there for that MKIV tone.

The clean is really great on the MKIV as well.

The shared "Crunch" is okay and can be made to sound great with the right drive pedal and the gain dialed back on the MKIV.

I found it can be a really nice clean with "grit" when the gain is dialed back on the Crunch Channel.

The lead and high gain rhythm on the MKIV is looser than the MKV and MKVII where they sound like someone placed a drive pedal in front of a MKIV to tighten it up more to get that modern sound/tone a lot of people like these days.

I have a combination of 6L6 and EL34 in the MKIV as well as some non-stock preamp tubes.

I never did a lot of tube swapping with the MKVII other than different types of STR440's and the stock STR445's.

I was curious to try some EL34's on the MKVII since they did make a MKV that I had owned a killer amp and not boxy at all but I had lost interest in trying them on the MKVII once I received a JP-2C.

Unfortunately, I had sold that MKV after purchasing the latest version of the MKV last year so I didn't get to check what type of EL34's were in it.

I could not take the loud popping from the MKV every time I had switched channels (the guy who purchased it was fine with it since he doesn't switch channels very often).

The latest MKV does have a different sound than the previous ones with the other transformers.

I think a little more modern sounding than the older ones.

 

[playingitloud]

I've been curious about how much bigger/punchier the JP2C is. To me my mark vii sounds as big and punches as hard as my multiwatt triple rectifier and as hard as my old mark III red strip with the ++ mod. It absolutely hits harder than I could ever make my mark v but I'm always so curious about the JP2c and the mark IV specifically the revision A. With all that being said it has been making me curious about stuff like kt88's in the mark vii

The JP-2C can definitely get a lot of thump/punch without much effort.

It thumps as hard or harder than my Road Kings and Roadsters.

I wish we did have more power tube options on all of these Mesa Boogie amps since it could make them become completely different beasts!!

 

[playingitloud]

JP2C punches harder than the Mark VII. It becomes more evident with a speaker cab change. Say the Boogie 410 cab. JP2C was epic, the Mark VII sort of not compatible with that cab. The JP2C has a bit of an advantage with the presence shifting capabilities with the pull knobs. You almost have to run the 410 as bright as you can since it will be mostly low end and midrange. The upper mids are not as abundant with that cabinet.

Then move on to a 410 cab with the V30, JP2C is a power house and has a characteristic grind you cannot get from Simul-Class or at least in the ilk of the Mark VII. Mark V90 is weak sauce in comparison.

How would you say the Mark III ++ compares to the Mark VII? That would be interesting to read your comments on that subject.

The MWDR has more sub harmonic low end compared to the JP2C, at the time, both amps had the STR440 grey coded tubes. The big difference was the JP2C works really good with a 7 string (not using the shred mode either) but with the MWDR it was just mud-fest.

Considering the Mark IV, Mark III and IIC amps, you get one or two more controls for addressing the gain structure that you do not get with the Mark V, Mark VII and JP2C.

However, when comparing the Mark VII to the JP2C, they are different even if they sound much alike. The grinders in the Mark VII are the crunch, VII, IIC and IV modes. IIB is more of a medium grind but decent enough if you figure out that mode. The JP2C has 4 grind modes too. Two of which are hidden features but are contained in the gain knob pull switch. Then there are two presence modes with the JP2C as they presence knobs have pull switches as well. Leave the sets of pull controls pushed in, CH2 is very similar to the IIC mode of the Mark VII and CH3 is much like the IV mode of the Mark VII. Where they differ is how the tone controls effect the gain structure. The midrange control on the JP2C will increase the gain level. I tried doing the same with the Mark VII and I did not have the same effect. The tone controls behave differently as well as the two GEQ circuits. I would not hesitate to get a second JP2V but the current asking price keeps going up. Sure after getting the second Mark VII, I found a deal on one of the Limited Edition JP2C that was much less than the investment. That one was reachable too, just a day drive and I would be there. It was tempting. If it is still available, I may get it.

I'm saving this reply since it will help provide reminders for experimenting with those JP-2C options/settings.

 

[playingitloud]

How would you say the JP2C compares to the Mark IV? Just out of curiosity.

I had been eyeing up the KSR amps for some time. Also looked at Driftwood and Mezzabarba. Then there was Dynamo Amplification and so on. Just never really got that interested in making a commitment. At the time, the JP2C was more affordable. Not now, but when I bought it new back in 2016 it was well under the asking price for the other amps. Also had that sound I was seeking. The Mark VII is different, similar tone and some of the Characteristic, just not as detailed with the same level of tone density. Most of that I believe is the difference between the Class A/B vs Simul-Class. I did not get the level of satisfaction from my Mark IVB combo when using a 412 cab with it. It was a decent amp but a bit boxy sounding. The Mark V was more of an ice pick and more of a boxy tone. I felt that both were a far deviation from the Mark III that I had. To me that was ideal. Should have held onto it. Just my opinion, we all have our favorites. The JP2C had that sound I missed that I could not get from the Mark IVB or the Mark V90. To be honest, I could never get that sound with the settings used on most of the videos people have shared. Only one time did the Mark IVB sound as epic after mixing a pair of SED =C=6L6GC tubes and TAD 6L6GC-STR tubes. I guess in respect to the Mark IVB amps, it made a huge difference with the Power tubes used. Are you using all 6L6 tubes or a blend of EL34/6L6? At least with the Mark IVB you can do that. Not possible with the Mark V90 or the Mark VII. It is either one or the other but not both at the same time.

Yeah, the SED =C= 6L6GC tubes sound really good in the Mark VII. I only tried them for like 30 minutes or so. Wonder what a pair of TAD red-base STR448 would sound like with a pair of SED=C= STR454 tubes. I will have to try that one of these days. For now, the STR445 yellows work well.

Good luck with the KSR. Interesting amp.

Yeah, it is a really interesting amp.

My buddy offered me his KSR Gemini (his band just broke up) for a trade of an FM9 and some cash so I could compare the Gemini with the Colossus.

I had a KSR Artemis (it's kind of a rack version of the Colossus) and sold it only to get a custom stereo KSR Artemis built but Kyle Rhodes ended up saying he didn't have the time to build it.

He recently said he can build me a custom amp (pretty damn expensive though and way more than any of his other amps, lol).

I want to see how many features from all of the KSR amps can I get placed into one "custom" built one.

 

[playingitloud]

Great overviews!
I'm getting ready to buy a vii and/ or a jp2c too.For all you out there that own or owned both; how are the " in between " sounds of each? Ie: mid or lower gain, chimey,sparkly,jangly tones?
I'm a shredder head all day long and i love the high gain tones of my iic+, & coli"s all day long ,but as usually is the case,every demo i see is for the crazy high gain metal chugga stuff.Surely there's got to be some real nice low gain tones in those amps? I would especially think on the vii- 2b mode?
Anyone stumble across any nice chimey low gain tones on these?

I play a wide range of style and the JP-2C is a little more heavy/agressive sounding to me even with the gains dialed back.

It feels more like "1-2" specific tones/feels done extremely well to me.

I believe the MKVII can be used for more styles and it does sound really good to great depending upon what tone you are after in an amp.

I found that I tend to play the same amp channels/modes on every amp so I thought the JP-2C did it best for me.

I have a JMP-1 that has been one of my favorite devices since I could set it up 100 different ways and use any of them.

I do wish more amps had the options to set up and save different settings.

 

[bandit2013]

I found the trick with the Roadster, Mesa 1990's 12AX7 Chinese Military 6N4-J Bejing Square foil getter tubes. Then top it off with the STR440 reds. Holy crap that amp now rips. Has a tighter low end and not so swampy with the sub harmonics such that I was able to use the 7 string guitar with it, no external aids like boost or distortion pedals. Same preamp tubes and then switched to the STR445 yellows, they were a bit over the top and killed the use with the 7 string but it was a beast on its own. I am glad I did not sell the Roadster, it has much more to it than I though. I did try using a parallel 39k resistor on the cold clipper to see if that would have much effect with a dop to 19.5k on the cathode, it neutered the amp completely, no more distortion and sounded like crap. Too much of a shift in the load line and raised the operating point more central so it was no longer creating the distortion in the cut-off region. Bad move unless you change the plate resistor too. So what if the cold clipper has less gain, it is not the gain that creates the distortion, it is where the operating point is on the load like that matters. No point in messing with it as it was prefect without the mod. Just the change in preamp tubes had a more desired effect.

Have not explored the STR445 in depth with the MWDR yet. I still like the STR440 grays in that amp.

Back to the topic at hand, Mark talk

I actually love both the Mark VII and the JP2C. Each have their own take on how the tone stack effects the level of distortion (what everyone calls gain). JP2C pull on the CH2 gain knob, almost feels like there is a shift in the opposite direction but not. You lose a bit of that detail but it is something useable, just have to dial the amp in differently. CH3 is the trick with the gain pull or pushed in. It is one of the few Mark amps that has the ability to switch from IIC+ to (IIC+IV) characteristic. Not a boxy sounding amp so change in power tubes just gives you that same good stuff. It may behave differently at bedroom level (STR440 and STR443 both have more low end bloom at reduced volume settings, compensate with the Shred mode) but more predictable or balanced tone with the STR445, STR448 and STR415 (running at bedroom level will have a similar tone like you get at gig level and no need to compensate using the shred mode).

I found the Mark VII to take on a boxy like tone with the STR415, STR448 and the STR440 tubes. Did not try the STR443. I did give the STTR441 a go and they sounded good, different than the 6CA7 tone you get from the STR445 which is to my liking actually. STR454 (=C=6L6GC sounded really good in the VII too, hard to get so I do not use them much, same would apply to the STR415).

I was not aware they were shipping the Mark V90 with EL34 tubes. I thought the Stockers to be the STR441 tubes. I did try the other tubes with the Mark V90 ice pick machine. I did not personally like any of them except for the STR441 or SED =C=6L6GC (Mesa STR454 tubes).