12ax7

  1. D

    Does it look like fake ECC83 / 12AX7 Mullards?

    I bought this tube as NOS mullard from Holland. Putted it in v1 of a vintage marshall and played for a while. Turned the amp off and some time later i noticed only this specific tube was simply looking different, it was white instead of black, and upon checking i realized it was just broke near...
  2. wonderingape

    What is the plate voltage for HT3 at V8b in the JVM410H schematic?

    As we can see, the plate resistor for HT4 at V7a is 220000, but I don't know what is the value for HT3 at V8b. According to this link https://www.ampbooks.com/mobile/amplifier-calculators/output-impedance/calculator/, we can calculate the unloaded gain for an individual gain stage.
  3. wonderingape

    Input and output voltages of JVM410 preamp

    What is the input and output voltage of JVM410H preamp?
  4. L

    HELP! New DSL100HR with low gain

    Hi, I just got a new DSL100HR. After seeing several demos and reviews of this amp, it's clear to me that it has a lot of gain, even without a boost. But I'm not getting that huge gain. Using the Ultra Gain channel, even on the red OD, with max volume and gain, I barely get enough distortion and...
  5. LucaMetalMyLife

    Marshall JCM 2000 TSL Preamp Tubes turn off

    Hi guys! I love my marshall head but I have a problem with it. When I play for 5 minutes the first 2 preamp tubes turn off and no more sound is produced by the preamplifier. If i plug the guitar in the return of the head the problem occurs but i can play without any problem for it is a...
  6. wonderingape

    Most suitable devices for very aggressive distortion sounds

    Noob question alert. In your opinion, which one of these things : 1. Power tubes such as EL34, EL84, etc. 2. Preamp tubes such as 12AX7 3. Solid state electronics such as integrated chips, transistors, diodes, etc. ...that will EASILY produce the most aggressive distortion that are mostly...
  7. Dwayne Eash

    Favorite preamp tubes for JCM 800

    So far for new production, I like mullard MU12AX7, but it's not quite high enough gain. I'm lacking singing sustain in my JCM 800 4010 combo with vertical inputs, no diode clipping, no channel switching. Seeking suggestions for slightly higher gain preamp tubes. Thanks!
  8. Mika555

    Marshall EL34 100/100 and his tubes.

    Hello people, i hope your are all safe . I have questiins about my marshall power amp, EL 34 100/100. I'm going to change all the 12 tubes for news ones. 8x EL 34 2x ECC83 / 12ax7 2x ECC 81 (phase inverter) --------------------- I made my choice for tung sol EL 34B, i...
  9. scott-colorado2016

    12AY7 in a cathode follower position

    Hi folks. I have a question: I have a Marshall Class 5 combo and I'm trying to reduce the gain a little. Right now, it gets slightly dirty at 9 o'clock on the volume using a Les Paul with a SD '59 in the bridge. I'm looking to get a little more on the dial, maybe up to 11 o'clock or so. V1 is...
  10. MPRawll

    12ax7 Signal Path Explanation - Ibanez Tsa30

    Can someone explain v1 and v2 to me? The triodes aren’t parallel... or in series? The signal path is somehow coming off the second cathode? It’s unlike any other preamp schematic I can find... I have modified quite a bit and started wondering about adding a cathode bypass cap for a gain boost...
  11. 1

    Unable To Remove Cover For 12ax7 Preamp Tube On Jcm 900

    Hello, first post here. I am trying to re-tube a Marshall JCM 900 Head with new tubes. I've run into a snag and don't know if anyone else has had this issue. I'm unable to remove the tube cover on one of the preamp tubes. For the other two, I just push down and turn counter-clockwise and...
  12. grainman

    New Mullard 12ax7

    full sounding....if you like that bell tone try one in v1 and v2 and a jj ecc83 in the pi...i think they add headroom and are great with pedals...not a hi gain tube ..but with a good od..man these tubes are cool.
  13. Rogueleader

    What Tubes Should I Buy???

    I recently bought a used jcm 2000 tsl 122. It is actually shipping now. Even though the seller says everything is in perfect order, I’m planning on replacing all tubes as soon as it gets home. I looked into the specs and says that it uses EL34s (svetlana), my question is which ones should I buy...
  14. grainman

    12ax7,ecc83 What Is Your Preamp Receipee

    We all claimed few times that we had THE solution for our golden tone with a mix of few new and old brands of preamp tubes....but things like they are ... it has to get to another level and there you are looking for a better receipee to improve your already tweaked tone....what is and will be...
  15. jmp45

    Current Production 12ax7 Recommendations

    My IA Blues 60 is in need of some new preamp tubes. This combo produces a lot of internal vibration and it can be bass heavy. I've been using EH, JJs and others. Looking for something that is warm, good harmonics and good microphonic rejection. Not looking to spend big $, the Marshalls get most...
  16. grainman

    What Are Your Favorite 12ax7's In V3,v2,v1 ?

    marshall amps tend to be very sensitive to 12ax7's ..which ones are you top favorites in v3 v2 and v1 ?!
  17. G

    12ax7 Alternative For Less "fuzzy" Jcm900?

    Hi all, I've been wondering about this for a while, and finally decided to look into altering the sound of my JCM900 4100 head. Please bare with me here, I'm not very well versed with the inner workings of valve amps so I may not be able to do what I want to do.. And all work will be done by a...


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