Mesa MarkV / Saturation 'mod'

[bandit2013]

I will not recommend removal of the C18 cap. My bad for posting such information earlier. Should wait and see how things go and then reveal what is good. That was difficult to replace but still manageable.

I will experiment with disconnect of the V6A mod just to get a feel how different the amp sounds with and without it. I did that one first before the GEQ mod. Wonder if there will be much of a difference. A pull pot would be ideal for that. I have no plans on drilling any holes in the chassis to mount a mini toggle switch but I may think about that and stick it on the rear of the chassis. A pull pot would be more ideal since that would not require drilling the chassis. Would rather leave the metal as stock as possible.

 

[APEMAN]

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[bandit2013]

The C18 removal was not a bad deal though, it sounded good but lacked the edge and it took away more than I expected. Without the C18 you wind up with bass dominance and single notes when played over a sustained chord do not ring out like they did with the C18. I much prefer having that note definition. Also pinch off harmonics and sustain were much better with the C18 than without. For me it was worth the experiment.

 

[mace]

hey everyone!
as I said before, I think there is one more easy thing that can be done. The ch3 treble and bass pot swap was a big win for my amp. It is so much easier to dial in the perfect amount of b m and t now. The sound became more open, feels like more headroom and definition in the gain character. It began when I measured the pot values. The bass pot with its 250k was fine but the treble with its 180k was far off so a simple swap was the cure here. If you feel confident with a soldering iron, give it a try! Cheers!

How does one go about measuring the resistance of the pot? Which contact points do you put the ohmmeter?

Should both bass and treble pots be 250k?

Thanks.

 

[user 41982]

How does one go about measuring the resistance of the pot? Which contact points do you put the ohmmeter?

Should both bass and treble pots be 250k?

Thanks.

You would need to desolder a pot to measure it properly. Turn the pot to "0" and measure the resistance going from the middle lug to the other two. One lug should read zero Ohms and the other would read your pot value.

After turn the pot to "10" and measure again. It should be the same result with the lugs switched.

On channel 3 the pot values are:
Treble: 200k log
Mids: 10k log
Bass: 250k log

The pot values for the other channels differ from that. Just check a schematic if you are unsure.

 

[APEMAN]

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[bandit2013]

I generally do not run bass past 11am, it generally stays between 9am and 11am. Also it depends on gain setting, voice selected and type of speaker being driven or what cabinet I am using.

 

[APEMAN]

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[IronSean]

As for the bass... I would never put the bass on CH3 on 100% - I use to set it to around 9 o'clock. Therefore, the pot swap changed my bass setting from 8:45 to 9:30 - which is fine for me.

Schematic values:
__T__M__B__C18_Model
190k 10k 250k yes MarkII
190k 10k 250k yes MarkIII
250k 10k 250k no_MarkIV
200k 10k 250k yes MarkV
180k 10k 250k yes MarkV apemans model measured value
250k 10k 250k yes JPIIC


Look here:
http://forum.grailtone.com/viewtopic.php?f=33&t=74669

In that thread you said all other amps have a 250K for the Treble pot, but it looks like only the Mark IV and JPIIC have a 250K pot for the treble pot and the 180-200K is in line with the other Mark series amps?

 

[APEMAN]

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[barryswanson]

So the JP-2C isn’t a true 2C circuit?

 

[APEMAN]

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[bandit2013]

...I wouldn't go so far, it is a frankenmark, using everything out of triaxis, markII to markV that JP loves with focus on the IIC+. It's treble pot comes from the markIV. And the result is awesome, using JPs ears as gauged reference was a good decision.

It may be a frankenmark but dammit, it sounds so good. How can an amp with midi and cab clone be a true IIC+? Not to mention three channels, two GEQs with a 16, 8, 4,4 ohm output taps. It is a modern design. Mesa claims that the TC-50 or TC-100 has the highest gain ever. Define the term gain and perhaps I will believe you. Take the JP-2C and blend it with the TC-100 or TC-50 and the combined sound just is more amazing than the amps on their own. Heck, even the Roadster with some changes to a few preamp tubes is a beast to enjoy. At least there is new ground to cover with the 12AT7 in the Mark V, that on its own has renewed my enjoyment with the amp. The bottom line is this, if you like what you hear and how the amp responds to your playing that is all that matters. Can you dial in the tone you need and does it sit well in the mix for those who gig? That small package of the JP-2C sure houses more power than my largest amp chassis. It may not have the 9 flavors of the Mark V, but I feel it is missing the tone and character I am getting from the JP. (mods included, it is closer to some extent but not).

 

[Wayno]

I think you guys are right on with your assessment of the JP2C. Having never played one or even heard one live I can't speak for it but I can imagine how good they are from what I have heard online. I believe it's as good as it can be, being true to the original iiC+ but relevant to the modern day too. It's always going to be a compromise, that's the nature of the beast, reissue a perfect remake, some people complain about the lack of truly independent channels etc. Would love to own one one day.

As for the Mark V, I need an amp to cover a lot of ground, and it now does that very, very well. Especially now with the mods, thanks for those guys! With my current settings I have three basic sounds that I can boost for three more different tones to give me 6 distinct sounds. That alone covers a lot of ground for my covers band. A few selective effects here and there and I'm set. Granted none of them absolutely 100% nail THAT iiC+ tone or THIS Marshall tone or whatever but I'd confidently challenge anyone to a live in the room blindfold test. More importantly than any of that though, I feel at last like I've found my sound in those settings and I'm getting better and better all the time concentrating on playing rather than tweaking. It will take something special, probably way out of my price range anyway, to make me trade in my Mark V now. I did consider trading it in for an Axe FX a while ago, glad I didn't. Maybe it's a placebo but I don't connect with transistors, I do connect with 12ax7's, 12at7's, el34's and 6l6's though. Happy days indeed!!!

 

[bandit2013]

It is too bad the Mark V cannot run an integrated quad like you can with the Mark III and Mark IV. (Actually it is mandatory to run the EL34 with 6L6 on the Mark III). Too bad I did not take the opportunity to try the 6V6 in the Mark IV when I had it. To date, I have not yet come to that magic that I had with the Mark IV running a pair of SED 6L6GC and TAD 6L6GC-STR. That tone was unique. I have not ventured the use of different tubes in the JP-2C yet. If one needs to insert a tube probe onto that amp to find its operating point you would have to remove the chassis from the shell as there is barely any room to get the tubes into the sockets as is. Since I never owned a IIC+ or other variety prior to the Mark III, it is hard to tell how the JP-2C compares. However, I would claim it is similar to the Roadster with some respects but has the attach and harmonic content associated with the Mark V. To some, they feel it tracks too slow where as the Mark V is on top of attack (more so with the mods). Those that have traded in the V to get the JP find themselves going back to the Mark V. I would think it is more of convenience vs versatility. JP can be dialed in to most of the tones offered on CH2 and CH3 of the Mark V. So in short it does take a step back on control settings and may need a decoder ring like the Mark III had in its manual. One plus is the FX loop of the JP as it is more compatible with all of the pedals I have including those that will not work with the Mark V. Just add a Mesa grid slammer to the Mark V and you have the JP-2C essence. I feel that the grid slammer pushes the Mark V where it needs to be, that on its own will add another layer or level of tone to your Mark V sound.

When it comes to gigs and trying to mimic the bands you are coveting, take to heart that what you see on the outside or sitting on stage may not be the only source creating that tone you hear. What is in the rig behind the stage ? Go back to the late 60's or early 70's, generally there is more than one amp in use, and once you start adding amps each being slightly different it compounds the tone considerably even if the amps are the same (there is no such thing as being identical). Also it would be difficult to replicate every band as there is more to just the amp and cab as there usually is a larger system in use to deliver the sound to the stadium or gig. In some cases there may even be a hint of resonance from the drum set in the signal path from the other instruments. If I am playing in the studio where the drum set is, even with the snare wires released the drum set resonates with the guitar and make the room sound huge (adds ambience to some extent).

I will now quote the Rock and Roll Hall of Fame acceptance speech of Alex Zivojinovich (Lifeson) "Blah, Blah, Blah Blah, Blah Blah Blah". Considering that is all I do is blah blah blah, get to the point..... unfortunately there is no point....

 

[Markageddon]

https://www.youtube.com/watch?v=FXKmoYCO4gc

Mark III (12at7 in Phase Inverter), Cheap Strat copy, Squier Jazz bass (TS-9 tracks and straight-in-tones used in rhythm parts)

 

[Markageddon]

New Mark V development.

Tungsol 12AX7 type in V1, V2and 3 stock, V4 Mesa 12AT7, V5 and V6 stock BUT with another Mesa 12AT7 in V7, the phase inverter.
Inspired to do so after having done it in the Mark III and heard it erupt into a fury of pure, classy huge awesome.

All the brutality all the sweet 3d grind all the mids in the right place, no unpleasant frequencies.
Powerful input levels at V1 with the Tungsol, levels made managable again for the power stage by the v7... all channels superbadass.
Thats the end of my tonal quest right there, I think.
Im going back for more cause this is ridiculously fun to play as well as amazing sounding.

I highly recommend trying this configuration, let me know what you thought.

 

[mace]

New Mark V development.

Tungsol 12AX7 type in V1, V2and 3 stock, V4 Mesa 12AT7, V5 and V6 stock BUT with another Mesa 12AT7 in V7, the phase inverter.

I highly recommend trying this configuration, let me know what you thought.

Do you have the other mods from this thread like C39 snipping etc.?

I may try your mix, although I’ve been very happy with what I’ve had since doing the 12AT7 mod. I honestly don’t even remember what tubes I have running currently. I was running Doug’s tube cocktail with the Jan Philips 12AT7 in V6 (I think, or did I leave it in V4)? I think I left the Tungsol from Doug’s cocktail in V1, but maybe I switched to the SPAX7 from Mesa. I hate to check that one because it is a always a pain to get back.

Doug’s tube cocktail is (I had this at one time, and may still...I do not remember what I’ve changed out):

V1 - Tung-Sol 12AX7
V2 - JJ ECC83
V3 - Ruby 12AX7AC7 HG
V4 - Ruby 7025SS HG
V5 - Ruby 7025SS HG
V6 - Ruby 7025SS HG
V7 - Sovtek 12AX7 LPS

 

[Markageddon]

New Mark V development.

Tungsol 12AX7 type in V1, V2and 3 stock, V4 Mesa 12AT7, V5 and V6 stock BUT with another Mesa 12AT7 in V7, the phase inverter.

I highly recommend trying this configuration, let me know what you thought.

Do you have the other mods from this thread like C39 snipping etc.?

I may try your mix, although I’ve been very happy with what I’ve had since doing the 12AT7 mod. I honestly don’t even remember what tubes I have running currently. I was running Doug’s tube cocktail with the Jan Philips 12AT7 in V6 (I think, or did I leave it in V4)? I think I left the Tungsol from Doug’s cocktail in V1, but maybe I switched to the SPAX7 from Mesa. I hate to check that one because it is a always a pain to get back.

Doug’s tube cocktail is (I had this at one time, and may still...I do not remember what I’ve changed out):

V1 - Tung-Sol 12AX7
V2 - JJ ECC83
V3 - Ruby 12AX7AC7 HG
V4 - Ruby 7025SS HG
V5 - Ruby 7025SS HG
V6 - Ruby 7025SS HG
V7 - Sovtek 12AX7 LPS

No hard mods at all in my rig. Just swapped out glass!!! 8)
I see...! Yep try all stock Tungsol V1 and have V4 and V7 as your AT7s and you'll be in heaven I reckon.
I'll be stunned if you dont like it and what can be dialled in when its configured..
Just like I was when this was applied..! Keen to hear what you thought, I know you've been following this for a long old time.

Sounds amazing with stock Flying V passives. God only knows what it sounds like with EMGS...will test more extensively at vol tommorrow daytime. Serious tight powerful shake-the-room kinda stuff even with the casters on the 2x12..!!! And thats just IIc+ mode...!!! No fartiness, no mud. Just pure Boogie power, tone and clarity with increased pre-gain courtesy of the tungsol.. and reigned in and tightened/sweetened by the AT7age.

Gonna buy a couple more of those and a couple more AT7s, and get the V;25 to same spec. Next week hopefully!

 

[Wayno]

New Mark V development.

Tungsol 12AX7 type in V1, V2and 3 stock, V4 Mesa 12AT7, V5 and V6 stock BUT with another Mesa 12AT7 in V7, the phase inverter.

I highly recommend trying this configuration, let me know what you thought.

Do you have the other mods from this thread like C39 snipping etc.?

I may try your mix, although I’ve been very happy with what I’ve had since doing the 12AT7 mod. I honestly don’t even remember what tubes I have running currently. I was running Doug’s tube cocktail with the Jan Philips 12AT7 in V6 (I think, or did I leave it in V4)? I think I left the Tungsol from Doug’s cocktail in V1, but maybe I switched to the SPAX7 from Mesa. I hate to check that one because it is a always a pain to get back.

Doug’s tube cocktail is (I had this at one time, and may still...I do not remember what I’ve changed out):

V1 - Tung-Sol 12AX7
V2 - JJ ECC83
V3 - Ruby 12AX7AC7 HG
V4 - Ruby 7025SS HG
V5 - Ruby 7025SS HG
V6 - Ruby 7025SS HG
V7 - Sovtek 12AX7 LPS

No hard mods at all in my rig. Just swapped out glass!!! 8)
I see...! Yep try all stock Mesa 'cept V4 and V7 as your AT7s and you'll be in heaven I reckon.
I'll be stunned if you dont like it and what can be dialled in when its configured..
Just like I was when this was applied..! Keen to hear what you thought, I know you've been following this for a long old time.

Sounds amazing with stock Flying V passives. God only knows what it sounds like with EMGS...will test more extensively at vol tommorrow daytime. Serious tight powerful shake-the-room kinda stuff even with the casters on the 2x12..!!! And thats just IIc+ mode...!!! No fartiness, no mud. Just pure Boogie power, tone and clarity with increased pre-gain courtesy of the tungsol.. and reigned in and tightened/sweetened by the AT7age.

Gonna buy a couple more of those and a couple more AT7s, and get the V;25 to same spec. Next week hopefully!

Interesting, I will give this a tryout at the weekend too!