Mesa MarkV / Saturation 'mod'

[psihiatros]

V1) Tungsol 12AX7 Goldpin
V2) Tungsol 12AX7 Silver
V3) Tungsol 12AX7 Silver
V4) Mesa 12AT7
V5) Tungsol 12AX7 Silver
V6) Mesa 12AX7
V7) Mesa 12AT7

Try that config. It sounds/feels awesome on my V.

Ive got an equivalent setup in the V:25 and Mark III too.

Its worth noting that the Mesa SPAX7 is also good for V1, but the its sounds like it has like a more modern/selective frequency thing happening compared to the Tungsol Goldpin. Both are good for introducing high sound/power-to-noise ratio. (All the sound, less of the hiss.)

Thanx a lot! What about power tubes and rectifier tube?

 

[Markageddon]

Power tubes and rectifier tube are standard still.

You're most welcome. \m/

 

[APEMAN]

-

 

[Wayno]

Hi all,

Long time no post.... work sucks hey!

Still more than happy with my Mk V. At7's in V4 and V7, couple hardware mods and she's singing like a bird released for me. Biggest difference is defo in the At7's though. Thank you again APEMAN and everyone who's contributed to this massive thread, this amp screams like a banshee!

 

[psihiatros]

Power tubes and rectifier tube are standard still.You're most welcome. \m/

Thanx again bro

 

[psihiatros]

...you really have to try the GZ34 rectifier tube... it makes the 10Watt mode so much bigger - it made it my favorite mode.A view month ago I finally found the key to (hardware-) mod this amp and throw out the parts that from my perspective don't belong there. Since then, I'm struggeling with myself to start a new mod threat here.All I want to say is, the "wrong" things (ear piercing frequencies) we hear in CH3 have a hardware reason - there are a view parts and values that differ from the mark II - IV generation and my guess is that mesa changed those values to make the EQ more transparent sounding (- afaik, your c-ness is a nonEQ model). Apart form that, I fine tuned my amps gain structure more into a mark III direction, made the 2C mode 'deep' and brought the "volume 1" control back to my amp (vial dual pot on the gain position). Now, with all 12ax7s it is almost impossible to make CH3 sound bad and the possibilities in combination with the 3 modes seem to be endless. It is totally crazy, because I would call this mod the "mesa mark mod". The JP2C got the original values too - funny, apart from its big transformer, it seems to be a "mesa mark mod"-markV.Looking back to the 12at7 mod, it kind of compensates the negative effects of the "new" part values. I'm happy to see how many people like it

Hi there, I'll sure give it a try
You know,
about your mesa mark mod, I think you should do it.
Make a thread just for that, explaining every single detail and change value you made. That way, everyone like me (who is completely useless with an iron in his hand) could just print the whole recipe and give it to his amp tech. You could even make a video for it and upload it to YouTube. Also a comparison like before/after etc. so we could see and hear the difference in sound.
That way, every one who is interested, can have his mark v modded with your mesa mark mod
Who needs a JP2C anyway

 

[Timu]

@APEMAN
I agree you should definitely start the Mesa Mark V mod thread.
As a junior electronics engineer, I am quite interested in understanding the modifications and how they would explain the current tone character of the amp!

 

[bandit2013]

It has been a while since posting in this threat. Those that are joining in, keep it simple, no need to do any hard mods to the amp. 12AT7 in V4 is ideal. I will have to try one in V7. I think what happed before when I tried it was the tube I was using. I recently got a VT1000 tube tester and found I had one that did not have matched triodes. This is not Mark V related: I tried the RFT12AT7 in the phase inverter of my Roadster. Boy did that tighten up things more than I expected. :shock: I was reserving the JAN/Phillips 12AT7 for the Mark V.

 

[Markageddon]

Been saying that for ages.

V4 + V7 = Turning it up to 11. 8)

 

[Thaymz]

Been saying that for ages.

V4 + V7 = Turning it up to 11. 8)

I am very excited for this now. Is v7 accessible without removing the chassis?

Cheers
Themi

 

[Markageddon]

Honestly couldnt say, for sure as when Ive done it ive always removed the chassis.
But IIRC it probably could be done by taking out the power tubes and recto tube in order to access it.
(Its the one behind the Rectifier tube.)

 

[Thaymz]

Perfect - Yeah in that case I should hopefully be able to reach in.

Cheers

 

[Markageddon]

You're most welcome.

Let us know what you thought..!

 

[reganjeremy]

Hey all. I've now made it through this thread twice. The first time through I ended up buying a mark iii just because I was tormented to know what it could actually sound like in comparison to the mark v. Well that was a good choice and I love it, but I also have been able to find tube substitutions for V4 and V6 of the mark V that make it great in its own right, although still very different from the mark iii sound.

What I first tried based on what I found in this thread was a 5751 in the phase inverter. That came right back out, as I found that it does change the character of the amp but made it far too bright for my taste, and I know some people have commented similarly. The next thing to try was a 12at7 in v4, which I had read here was the most common replacement. I was pretty happy with how it affected ch3, but it still didn't really do it for me in terms of what I had been searching for. The next step was to try out "something" in the V6 slot, but I was out of 12at7's to try. So I tried out a Westinghouse 12ay7 that I had bought a pair of at some point. I didn't read very many people trying this tube for the mark v, but I figured that it should still be mostly ok. I was very impressed with this combo, and ultimately tried putting in both 12ay7's in v4 and v6. Then I was able to start getting the changes that were talked about here: tighter bass, smoother gain, and less grainy highs. To me, this is the magical combo. I am pretty sad though to find out that that batch was the last easy to find 12ay7's from westinghouse, as now most poeple have realized how good they are, at least i'm guessing? I know that they are rebranded from a few different actual producers, but they seem to be much more rare than when I bought the first set.

On the next run through of trying new things, I bought a genalex 12at7 and a Sylvania JHS-12AT7WA. I'm also picking up these 12at7 and 12ay7's for use in my headphone amp, so I have not had any fear of buying tubes that I didn't find useful in the guitar amps, as they are still useful to me .

So this pair, the genalex and sylvania 12at7's sounded very grainy. The high-end definition was incredible, obviously superior.. but so grainy I couldn't dial it out without darkening it up way too much. So maybe that's just a bad pair, or in the wrong order, or I should try to use one 12at7 and one 12ay7 to see where it takes me. I also found that the volume difference between the 12ax7's, 12at7's are similar in volume with a slight difference, but with the 12ay7's it is a very significant difference, which lets me dial in the volume and gain in just such a nice way.

Ultimately, I think the real mojo is found with the 12ay7's and I'm surprised that wasn't tried by more people. Because of that difference, I thought it was significant enough to tell you all here. I also have to say that I'm primarily focused on getting the sound I want out of the iic+ mode on the mark v because I like its smoothness and it just sounds so nice and warm to me compared to the brighter and more modern-sounding mark iv setting. So I think partly from reading through, the reason for some people was to just get a more usable mark iv or extreme mode setting, but for me I'm mainly stuck on the iic+. What I love really is setting it all up so I have mark i for ch2, mark iic+ for ch3, then moving over to my mark iii and comparing it... I'd say the mark v has a more "ragged" sounding high-gain sound where the mark iii is smoother, but I find that the mark v reacts more in a usable way when I roll off the guitar volume than the mark iii. The mark iii seems like just all-out, all the time, super metal-y type tone. I truly love it, but it's quite a bit less versatile.

Anyways, so can anyone actually confirm for me that using the 12ay7's for this purpose is completely fine? I have read that the plate voltage for the 12ax7's is 330mv, 300mv for the 12at7's, and if i'm reading correctly the 12ay7's also use a 300mv plate voltagte for the same current. Or is there any other contributing factor in this equation? Sometime i'm also going to start trying out the 12at7's that I have in the v3 and posibly other places to find out the effect on channel 2, which I find a lot harder to set up for the most part, but have found a few very heavy tones with a humbucker-equipped guitar.

 

[TStone2]

Hi. I've recently purchased a new Mk5 90W head. Channel 1 and 2 are impressive, channel 3 not so much. So, the quest begins here in this thread....
I've read quite a bit of the content here but not all 50+ pages. I swapped in mesa 12at7's into V4 and V6 and a (SPX into V1 to try to help noise reduction). I was somewhat impressed with the tonal results in channel 3 but not fully convinced it's at full potential. So, I ordered 2 Jan/Philips 12AT7's from tube depot, they arrived Saturday, popped them into V4 & V6 and the results are very good. I have not done any hard mods to this amp because it is new with a 5 year warranty. To my ears, this biggest improvement is in Mk 4 and Extreme modes. IIc+ is improved but not to a true c+ tone in my opinion. My first Mesa was/is a Stiletto Stage 1 Trident so I know ALL about transparency, i.e. this thing really exposes flaws in your playing. The Mk5 does the same. It's a real slap in the face to get you're sh## together as a guitar player. Bottom line: no more buyers remorse for the Mk5 purchase. Not sure if this has been covered....I have 1 question, has anyone tried the hi-gain version of the Jan/Philips 12AT7 available through tube suppliers ?? I purchased the 2 with low noise/low microphonics for an extra 4 bux a piece. The hi-gain are an extra 2 bux per. Thanks to all that have contributed to this thread. The Mk5 is a keeper.

 

[reganjeremy]

TStone2 what speaker are you using? I finally got to try my mark V with an EVM-12L speaker and I have to say it really impressed me. Also, do you use the effects loop? I have found that it removes a lot of the high frequencies that may be making the amp overly fizzy. You should really try the effects loop.. to me without it I am not that happy with the amp on the whole. but with it, I am in love with it.

 

[TStone2]

reganjeremy. I'm using a Mesa Recto 4 X 12" with 4 V-30's. It's 10 years old and speakers are well worn in. I like it. I do use the effects loop with an EQ, EQ is off but loop is active. I'd like to try different speaker combo's when $ permit but for now I'm liking it. I also have an EVH 2x12 cab with Celestion G12 Heritage speakers, running the Stiletto through that with fairly impressive results. The G12's help tame the high end on that amp. Will be checking out the MK5 through that cab soon. Thanks for the reply !

 

[emeprod]

I apologize if I'm beating a dead horse, but, can somebody tell me what specific tubes are being swapped in this mod for a mark 5:25? I know that the general consensus was V4 and V7 in the big Mark V, but I don't know which specific tubes in the 5:25. Thanks.

 

[Markageddon]

Hi no worries. People find this at different times! So don't feel awkward...!
The equivalent mod you speak of is Mesa 12AT7s in V2 (For gain stage flavour, ability to dial more gain/preamp EQ etc without flub) and V6 (Phase inverter for the big 3d vintage smoothness across all modes/both channels)
A Goldpin Tungsol or Mesa SPAX7 in V1 for a input stage purity/massiveness too.


Hope this helps.

(The same config works for the 35 too, btw, for anyone interested.)

 

[Bankim]

Been saying that for ages.

V4 + V7 = Turning it up to 11. 8)

I am very excited for this now. Is v7 accessible without removing the chassis?

Cheers
Themi

I usually remove all the power tubes n the rectifier tube and reach in with a flashlight. Not the most convenient but gets the job done. Plus, I have smallish hands, ymmv