new 12ax7

[mkstylee]

Hi all,
Has anyone fitted any different 12ax7 pre valves to thier yjm if so what were your thoughts?

[John 14:6]

The YJM00 comes stock with a red Marshall labeled JJ in the first gain stage under the can. The rest of the white labled 12AX7's are Shuguangs. I pulled the stock V2 second gain stage tube and put in another JJ. That made huge difference in taming any shrillness when using the booster and it also made the boosted and un-boosted signals balance a lot better.

[mkstylee]

Thanks john
Can i ask why v2 and not v1 ? how does this alter more than v1?
I've got a couple of old mullards and telefunken's and would i benefit from putting them in v1 and v2? It's the v2 thing that's got me thinking.

[John 14:6]

Thanks john
Can i ask why v2 and not v1 ? how does this alter more than v1?
I've got a couple of old mullards and telefunken's and would i benefit from putting them in v1 and v2? It's the v2 thing that's got me thinking.

Because there is already a stock JJ 12AX7 in V1 spot under the can. This way you will end up with a JJ in both gain stages and get rid of the Shuguangs influencing the tone of your amp. Play around with tubes and find out what you prefer. The V2 tube swap is all I have done and I think it made a big difference. It made a big difference with my JVM also. The JVM had the same tube set up from the factory.

[Doc Holliday]

I've tried various tubes and ended up putting in Tungsol in v1 2 and 4 and a ehx in 3. It sounds great. I put a mullard in v1 but.. In this amp the Tungsol sounded better. It sounded bigger and ballsier. I would defo try one in v1. The jj didn't stand a chance. I've tried ei elites also. Great tubes but as with the telefunkens not for marshalls IMO. Not enough beef.

[John 14:6]

I've tried various tubes and ended up putting in Tungsol in v1 2 and 4 and a ehx in 3. It sounds great. I put a mullard in v1 but.. In this amp the Tungsol sounded better. It sounded bigger and ballsier. I would defo try one in v1. The jj didn't stand a chance. I've tried ei elites also. Great tubes but as with the telefunkens not for marshalls IMO. Not enough beef.

I found Tung Sols too bright and shrill in my Splawn and JVM. I have not tried them in the YJM100. JJ 12 AX7's always warm up a bright amp.

[mkstylee]

cool fellas this is what i'm after lots of opinions.
In my valve arsenal i have,
telefunken
mullard
groove tube
ruby tube
EI
edicron
jj
cvc
shangung?
I'll give em all a go this weekend and report back with my findings.

[Doc Holliday]

I've never been big on jj's to be honest. To dark for my liking and breaks up to early where I like a little more headroom. Although I agree as an all round valve they have a descent gain, they are cheap .. Still I feel they are inferior to the new sensor tubes. It did a good job an my dsl but my plexi is not overally bright.

[mkstylee]

Thanks john
Can i ask why v2 and not v1 ? how does this alter more than v1?
I've got a couple of old mullards and telefunken's and would i benefit from putting them in v1 and v2? It's the v2 thing that's got me thinking.

Because there is already a stock JJ 12AX7 in V1 spot under the can. This way you will end up with a JJ in both gain stages and get rid of the Shuguangs influencing the tone of your amp. Play around with tubes and find out what you prefer. The V2 tube swap is all I have done and I think it made a big difference. It made a big difference with my JVM also. The JVM had the same tube set up from the factory.

will v1 regardles of make ,make the most tonal difference being first in line ?

[John 14:6]

Thanks john
Can i ask why v2 and not v1 ? how does this alter more than v1?
I've got a couple of old mullards and telefunken's and would i benefit from putting them in v1 and v2? It's the v2 thing that's got me thinking.

Because there is already a stock JJ 12AX7 in V1 spot under the can. This way you will end up with a JJ in both gain stages and get rid of the Shuguangs influencing the tone of your amp. Play around with tubes and find out what you prefer. The V2 tube swap is all I have done and I think it made a big difference. It made a big difference with my JVM also. The JVM had the same tube set up from the factory.

will v1 regardles of make ,make the most tonal difference being first in line ?

Yes. That is why Marshall uses JJ's in the V1 first gain stage of their amps. At least they do on the JVM and YJM100.

[mkstylee]

thanks john,think i'm gonna try a mullard in v1 and a jj or tung sol in v2,cheers for the help

[John 14:6]

We all have different tastes. Some people love JJ's and other hate them. Same thing with Tung Sols. I found that when I used Tung Sol pre amp tubes my amps were way too bright and shrill. I could not dial them in to sound right. JJ 12AX7's have always fixed that for me. The New Sensor reissue pre amp tubes have a lot of fans. The New Sensor power tubes (especially their Mullard EL34's) do not stand up to high plate voltages very well. The Mullards reissues sound great, but they are not reliable.

[mkstylee]

Right fellas,
After a day of valve swops and different config's i have come up with what suites me and my amp best,here goes.
v1 old 60's mullard
v2 tung sol reissue
v3 jj cryo (harma)
v4 jj cryo (harma)
changes this amp from mild mannered to insane bad ass ,i've already put the back cover back on as i know i won't be changing any time soon and just bought 2 old blackburn matched mullards off ebay, testing 100%so seem all good . so i can keep this tone going in years to come,might give the 2266 one .I was not convinced at the mullard mythology but after fitting my first in the yjm i'm a convertee.The only improvement i could make on this is to get some harma cryo EL34's

[Doc Holliday]

The mullard and Tungsol have a great 3d effect to the tone. Good combo! I personally would leave the power tubes stock. They are svetlana winged c's and are considered to be up there with the best of new production el34s.

[mkstylee]

The mullard and Tungsol have a great 3d effect to the tone. Good combo! I personally would leave the power tubes stock. They are svetlana winged c's and are considered to be up there with the best of new production el34s.

Yea it does sound nice now ,really nice but some watford valves ,harma cryo treaded mullard clones are on the way so i'll update after they are fitted' read only good things about watford's cryo stuff.