Time to re tune the pre’s (DR MW)

[Dreamin90s]

Picked up a used 2018 mesa dual recrifer multiwatt. I think v1 might be going microphonic.
I already swapped out the 6L6 str 440’s (blu 10) that were still factory. At the time Mesa was out of el34’s so I got a quad from Eurotubes. I ran el34’s in my rev g back in the 90s. Helped with the mid scop. I pulled v1, guy at Eurotubes said yes, that appears to me a Mesa branded JJ, not Chinese that some got.
I’m not displeased with the tone, I do feel this thing doesn’t have as much gain as my old rev g but whatever… I was going to start with just v1 & v2… I’ve read somewhere that the Mesa branded JJ’s have a little less gain than straight up labeled JJ’s, true?

I’m not really a lead player, more rhythm stuff. Tones I like are soundgarden, aic (I know Jerry used Marshalls, but I use el34’s lol) pretty much moderate to high gain 90’s heavy rock..I’ll hit the modern channel sometimes for stuff like the Melvin’s, deftones white pony era etc… I play Les Paul’s with 498ts, 57+ and burst buckers… I don’t boost the amp. I run it on spongy with the recto tubes…


Thoughts on a tube for v1 or 2? Oddly I decided to ask ai lol, it suggested a electroharmix in v1 the Mesa spax7 in v2 keep the stock mesa jj branded in 3-5…. Pretty crazy it spit that out when I told it the head I have and the tones I like…

Anyway, i think this amp is plenty bright, I like more a darker, wall of sound tone, but I do like note clarity as I play a lot of full chords and distant dropped tuning chords. I prefer to live on “vintage” (the old orange) on channel 2.

Suggestions on pre amp tubes to give a try in at least v1? EH, Mesa branded JJ’s (is that still what they are using?), regular JJ’s, Mesa spax7?

Thanks!

Ps - any trick to doing the pre’s ? I got lucky pulling v1 out and putting it back in. You can not see anything, just feel and pray.

 

[DrKev]

I’ve read somewhere that the Mesa branded JJ’s have a little less gain than straight up labeled JJ’s, true?

I've not aware of actual measurements anywhere to suggest that is truly the case.

Suggestions on pre amp tubes to give a try in at least v1? EH, Mesa branded JJ’s (is that still what they are using?), regular JJ’s, Mesa spax7?

JJs are good tubes. I've had no issue with them for 20+ years. The bonus (in my opinion) is that they are a European Union company and factory and thus bound by better employee protection, health and safety, and environmental laws than any other country making vacuum tubes. And they're not Russia. In my book, that's a very easy choice.

In my amp V1 seems to be the most sensitive to noise and microphonics so I use that as my test bed. I use a looper, or plug my iphone into the front of the amp with a test tone or white noise, clean channel run clean, run a mic or effects send to my DAW, put different tubes in and pick the ones that give the best output and lowest noise. Yeah, it's a lot of work but I enjoy that (and 'thanks' to Long Covid, I have the time to do it, if I have the energy). In doing that I've never noticed a particular brand or tube come out ahead of any others.

 

[bandit2013]

I have a 2018 MWDR. All preamp tubes were Mesa branded JJ tubes ECC83s. Rectifier tubes 5U4GB are EHX and the Power tubes were the STR440 (Grey) Chinese Shuguang tube that Mesa forced on us for a few decades. Actually, I sort of prefer the STR440 tubes in the MWDR and I have plenty of backups of that tube. I did try the STR445 but did not care much for the end result.

Tung Sol or EH 12AX7 tubes will be on the bright side. The Mullard CV4004 has similar gain but not as bright with a slight midrange scoop. I have not explored that many preamp tubes in the MWDR as I have with the Roadster. Different amps but similar circuits. Roadster is much darker sounding than the MWDR.

 

[Dreamin90s]

Yeah I don’t want brighter… I switched to el34’s. That’s what I ran in my rev g. Guess jj’s are the best play here for me idk…

 

[afu]

The aforementioned CV4004 is dark. If the brightness is a problem, that could be your fix.

The AI probably told you EHX in V1, because it's good at stopping noise. I put those in a Supersonic 22 and it went from unusable to dead quiet.

If you're looking for high gain tubes, the Ruby 12AX7ACZ is a JJ which has tested above the normal gain of 100. I get mine from Doug's tubes. He tests his preamp tubes and writes the gain on them if it's critical to the description.

The Ruby 12AX7AC5 HG is meant for V1 or other positions where you don't want thermal noise from the valve. I've used these in V1 for my old Rectifier.

Doug's Tubes 12ax7s

 

[bandit2013]

The tone stack driver, it is best to keep the Mesa branded JJ tube in that spot. V3 is a dc coupled cathode follower which is hard on most tubes. JJ ECC83s or a Chinese 12AX7/7025 will be best. V4 is also a cathode follower, not as hard on tubes but again, JJ #ECC83s (Mesa 12AX7) or Chinese 12AX7/7025. All of the other tube positions are fair game to use what you want. CV4004 for example. As for the phase inverter, Mullard long plate 12AX7 is good too, a bit more robust than the LPS.

I would remove the amp from the head shell, that way you do not have to keep removing the power tubes to swap in preamp tubes. Turn off power when changing the preamp tubes. That is how I do the tube rolling. Note that the JAN/GE 12AX7WA will work fine in the cathode follower locations V3 and V4 but may be a bit on the bright side. They helped the Roadster which is a much darker amp that needed to be brighter. I eventually ended up loading the Roadster with all old Mesa 1990 Bejing 6N4-J military tubes that mesa used back then. That was the first time the 7-string was compatible with the Roadster.

I even experimented with JAN 5751 tubes as well. The image is just and example and is not the MWDR. Roadster has the same V3 tone stack driver but moves the FX tube to V5 as V4 is used for the reverb. For this example I had the Mullard long plate in V2 and V6 (phase inverter). I should revisit this with the Mullard CV4004 just for fun. I think doing the tube roll in the MWDR would be interesting. Been a while since I ran with the Dual Recs. I sort of wonder if the RFT in V2 would make a change. That tube is one of the most dark/aggressive tubes I have used. However, it was recommended not to use it in V1 of the Roadster as it would have a short life in that position for some odd reason. Tung Sol is a bit brighter than the Mesa branded JJ ECC83s, The EHx is about the same, just a different gain characteristic. CV4004 has the same plate structure but may be different control grid and cathode design. They look identical but sound different.

This is a graphical representation of the tube task chart for the MWDR. It identifies where the Cathode follower circuits are (in purple). I only wish I had the schematic for this amp to see what components are different from the earlier versions as that would be helpful in tube selection.