12AU7 in V2 of 5E3

Discussion in 'Amp Tech Center' started by Bones, Oct 21, 2017.

  1. Bones

    Bones Telefied Ad Free Member

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    Been doing some reading while waiting for new tubes to show up and one suggestion was a 12AU7 in V2, I happened to have one in my spare tube box and dropped it in. It definitely "fixed" some of the things that I wasn't enjoying with this amp. There's definitely a volume drop. There's definitely way less noise and hiss. The amp is now super quiet with no signal going through it. Before there was a lot of hiss even when nothing was plugged into it.

    The bass may be a little less flubby with my Les Paul, but this may be a bit of a placebo effect or the result of the volume drop?

    Also sounds cleaner, more headroom, which seems to suit my pedals a little better.

    I think it definitely made it a better "bedroom" amp

    Anyone else use a 12AU7 in V2?
     
  2. Dacious

    Dacious Poster Extraordinaire

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    By dropping gain, you have reduced everything. If you have an original unmodded circuit, have you tried a 12AY7 in V1?. That combined with having the unused channel up a bit, is a way to reduce flub. Remember when the Deluxe was created and developed the hottest pickups it was intended for were singles. You'd be better to plug into the 2nd input to cut gain in the front-end.
     
  3. Bones

    Bones Telefied Ad Free Member

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    it came with 12Ay7 in V1 and 12AX7 in V2 it sounded OK, then it didn't it got really noisy and I thought maybe the tubes were bad as they were barely glowing, so I put in another set and while the "new" set did perk up the amp a bit, the hiss was amazingly loud.I did some poking around and re-soldered a few connections, but there was still a loud hiss. Putting the 12AU7 in V2 got rid of the hissing completely. Maybe both previous tubes were bad, but the amp is almost dead quiet now and sounds great. I have a new 12AY7 on the way, so maybe it will be fine once I load that into v2. Maybe how it is now wouldn't sound good to others, but it's the best the amp has sounded since I bought it.
     
  4. Dacious

    Dacious Poster Extraordinaire

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    It's your amp, so if it sounds good to you that's all that matters. 5E3s are braappy and can be rude and farty. George Martin refused to record Lennon's because it was so noisy. If you have the original scemo with the heater leg grounded through the chassis.....

    Did you look at the cathode bypass cap? If they're soldered too close to the cathode resistor they can overheat.
     
  5. Ricky D.

    Ricky D. Doctor of Teleocity

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  6. Wally

    Wally Telefied Ad Free Member

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    Is this an actual vintage 5E3? If so, what service has it had?
     
  7. Bones

    Bones Telefied Ad Free Member

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    Oh, I should have been more clear, this is a clone that I bought last spring. I'm still learning about it, but it was definitely a little bit of a sloppy build, but I got it for less than the price of a kit. I did lift the cathode bypass cap away from the resistor. The heater leg is grounded through the chassis and it also appears that the pots are grounded to the chassis, soldered directly onto it, with the pre-amp grounds going to the back of the "normal volume pot. In other words there's no pre-amp ground bus per se. This seems iffy to me as I don't trust that blob of solder on the chassis.
     
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  8. Bones

    Bones Telefied Ad Free Member

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    no it's a clone, I forgot to mention that
     
  9. Bones

    Bones Telefied Ad Free Member

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  10. Dacious

    Dacious Poster Extraordinaire

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    OK, that bolted on earthed pot is a likely candidate. I'm not a fan of star grounds but any dissimilar metals with current will corrode where they meet. I would solder a wire across the back of all pots and jacks and ground that to the chassis through solder, or a serated washer under a trans bolt.
     
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  11. Bones

    Bones Telefied Ad Free Member

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    Great, thanks!
     
  12. D'tar

    D'tar Friend of Leo's

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    You're not the only one...:) Mine sounds good with a bunch of different compliments. This isn't mine but I think it sounds fantastic. Great recording amps!

    12ay,12au,6v6,5y3 w/attenuator

     
  13. robrob

    robrob Poster Extraordinaire Ad Free Member

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  14. Bones

    Bones Telefied Ad Free Member

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  15. robrob

    robrob Poster Extraordinaire Ad Free Member

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    "Can I do this and the Pre-phase inverter MV on the same amp?"

    Yes you can, they're both good mods.
     
  16. PhredE

    PhredE Tele-Meister

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    Admittedly, it's been a while since I looked at the spec sheet(s), but as a reminder:

    I think most everyone knows the 12ax7 has high gain factor and the 12au7 is one of the lowest. One nice side benefit of the 12au7 is it has a wider freq. response. The specs call for something like 20Hz-20kHz IIRC.

    Check out related NoS tubes in the 12au7 family as well: 5814, 5963, 6189 - these can be really amazing in the right amp (preamp). In any case, it's your amp -- if it sounds good, go with it! Best of luck.
     
  17. DennisM

    DennisM Tele-Meister

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    The same thing happened to my 5E3 build. Waaay to loud and obnoxious for the bedroom. Noisy, humming etc. I had the EH 12AY7 in V1 and a JJ 12AX7 in V2. The (new) JJ 12AX7 started 'frying bacon' (after only a few months) and I had nothing but a 12AT7 laying around so I put that in V2 to see if the 'frying bacon' went away. It did, and the amp sounds absolutely wonderful with the 12AT7. Now it's not a super loud, unusable beast. Great bottom end and still has that great deluxe sound...just WAY more manageable. Like you, this 5E3 amp has never sounded this good since I built it. The 12AT7 stays :)
     
  18. mherrcat

    mherrcat Tele-Holic

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    Great word, “braappy.” That’s the sound I described as “ratty” in the thread I started about Pre-PI MV wiring.

    I’m going to try the PI MV and the NFB switch in mine. The 12AU/AT swaps sound interesting, too, since the MV and NFB mods both allow the option of an “unmodified” setting.
     
  19. zook

    zook Friend of Leo's

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    If it has Carbon Comp 1/2 watt plate resistors they are a source of hiss. I use 1 watt carbon film with great success.
     
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  20. ce24

    ce24 Poster Extraordinaire

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    Adding the negative feedback mod is your friend..... Cheap easy and it switches back to original with the three way switch...... Nothing not to like butt lots to love.....
    Cheers.
    Ha... just saw Rob's post...... Do this....: )
     
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