1. #1

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    A while back I bought a Carvin V3M. (50w tube. ) The only tube amps I’ve had any experience with are a 70s Twin and a couple of Music Mans. (Oh, and a ~50 Fender Deluxe.). But that was a few decades ago. So I was interested in experimenting with a tube and that could do clean, AND searing lead. I loved EVERYTHING about the V3M, except that I wanted a bit more clean headroom, even on the clean channel at 50w. So I sold it. Recently I was wondering if I could do a tube change to get a bit more clean headroom. It has (4) 12AX7 and (4) EL84. I know very little about this stuff, so I was hoping you folks could offer suggestions, or just nix the whole idea. Carvin went under a while ago, and now these amps are in demand. Of course ?


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  3. #2

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    sure, changing the 1st 12ax7 for a lower gain tube like a 5751 (my preference) or a 12ay7 can do that for you. but it could also alter the basic tone/feel in a way you might not prefer, or move that sweet spot so you'd have to crank it anyway to get it where you want it, and so on.

    it would probably be fine, but it could have unintended side effects. or it could be exactly what you want. or one tube might be amazing and the next trash. you never know until you try. i've had it go both ways, where it nerfed the amp to the point i preferred the 12ax7 or it lowered total gain available, sweetened the cleans immensely and added whole new tonal/gain shades along the volume/gain knobs that weren't there before.

  4. #3
    Thanks. The amp has 3 channels from clean to crunch to crazy. I was thinking if I made the clean channel louder and cleaner, there’s still plenty of dirt on the other two. No?

  5. #4

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    it really depends on the tube in question. here's a rudimentary chart i googled up:

    Tube Gain Acceptable Substitutes
    12AX7 100 5751 12AT7 12AY7
    5751 70 12AX7 12AT7 12AY7
    12AT7 60 5751 12AY7
    12AY7 45 5751 12AT7 12AV7
    12AV7 41 12AY7 12AU7
    12AU7 19 12AV7

    the "gain" refers to the tube type's relative gain; if a 12ax7 was a "10", then a 5751 would be a "7", and a 12ay7 would be a "4.5". that will give you an idea of how much shove you'd be giving up by swapping in a different tube type. and there's plenty of variance between nos and new and brands and all that between every tube type of course. so maybe one tube is pretty good all around, and another is amazing with the cleans but you hate what it did to your gain channels and so on.

    for instance, i wanted a little more headroom for my ac4hw (4 watts). but the 5751 made it sound like oatmeal. it was just flat and dull and had to crank it louder to get to where i wanted to be which defeated the purpose of the extra headroom. so i just stuck with 12ax7s. they got dirty faster on the dial, but they had "life".

    on my trusty old three channel peavey, a 5751 turned the cleans from endless bland cleanliness into a fendery sort of thing. the crunch channel went from off on 0 to distorted on 1 to death metal on 4 to having cleans and break up and crunch and so on before getting to metal. the ultra channel went from crunch to stupid amounts of gain but it just took longer to get to max gain and saturation.

    it's like it lost a gain stage, if that makes sense. which was a trade that i was willing to make, because with an overdrive i was more or less back to where it was before, except i gained all these new tones that i liked more than what i sacrificed to get there.

    as a super extra added feet bonus, it just so happens i have a carvin v3m model in amplitube 5. i gave the three channels a quick spin and yeah, i'd do it if were you. the cleans were surprisingly nice but they took a while to get going, the middle channel lacked nuance and both gain channels were a bit thick and tubby. not that i fully got the amp in the 20 minutes i spend with the fake version, but i think it's worth the $20-30 to find a decent nos tube and give it a shot. you can always add a pedal to get back what you lost and if you hate it, it takes 2 minutes to try another tube or put the old one back.

  6. #5
    @feet: Thank you so much for the comprehensive evaluation and advice. Now I just have to start looking for a reasonably priced used V3M. Besides staying clean longer, does the clean channel gain any vol, stay the same, or lose vol?

  7. #6

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    Don't know for sure for the Carvin V3M, but V1 tube is not dedicated to clean channel only.
    Switch to a lower gain tube as suggested, you'll get a cleaner clean, and quieter, but also a cleaner crunch (and quieter, too)
    But IMO for the cost of 1 or 2 string sets, it's worth trying and is completely reversible.