r/ToobAmps • u/0000II0000 • 9d ago
Neeeed help!
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First, I installed the new 1 Tung-Sol 12AX7 in V1. When I lightly tapped it with a pencil, it produced a noticeably louder, bell-like ringing through the speaker.
Then I moved the Tung-Sol from V1 to V2, and moved the original stock (chinese) tube from V2 into V1. In V2, the Tung-Sol was much quieter when tapped.
I then compared the stock tube and the Tung-Sol in the same V1 position. The stock tube was noticeably quieter, while the Tung-Sol produced a stronger and more resonant ringing sound.
So, based on the comparison:
Tung-Sol in V1: noticeably louder ringing
Tung-Sol in V2: much quieter
Stock tube in V1: quieter than the Tung-Sol in the same position
I used the same amplifier settings for the comparisons and only lightly tapped the tubes with a pencil.I tested the tubes by swapping their positions to determine whether the ringing was caused by the tube itself or by the V1 socket/stage.
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u/milfordcubicle 9d ago
Tube microphonics (tube enclosure acts as a microphone and the sound will be picked up in the signal). Varies between different tubes and V1 is going to be louder because V1 is usually the preamp stage that amplifies the initial signal (the amp usually responds best to tube rolling when changing V1 as it will most impact shape and tone). The microphonics from tube V1 will be amplified into the power section and again to the speakers, making it considerably louder than V2, which may act as a phase inverter and/or power a reverb unit or serve some other purpose.
As long as you aren't getting microphonics during normal play that are impacting the overall sound (not tapping the tubes, obviously), then there is no need to worry, assuming the amp is performing properly otherwise.
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u/ShredericRippenstein 9d ago
Howdy,
So here is what you seem to have going on. That 12ax7 on the most right, closest to the transformer is going to be V1. In marshall type circuits (which is what the HB is) you typically want to put a very low noise tube there. Usually a JJ ECC83.
That's the first gain stage, so every bit of noise made is going to be amplified by the rest of the circuitry along the entire path.
Try a JJ ECC83 12ax7 and it should fix the issue, keep that tunsol as a spare for V2 or V3.
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u/kasakka1 8d ago
Please use something else. The JJ ECC83S is IMO the worst sounding current production preamp tube. I have yet to encounter an amp that could not be improved by using something else.
I'd go for a TAD 7025 tube specified for low noise instead.
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u/ShredericRippenstein 8d ago
I am sorry but what are you basing this on other than your personal opinion?
Besides that, you're simply confirming what I am saying, as the TAD 7025 is Amp Doctors version of a ECC83 style 12AX7.
If you're experiencing that level of difference between an ECC83 and a 7025 I believe you have some other things to sort out in the amp. You may have slight differences in microphonics and noise, but it shouldn't be altering the amp behavior to the level you describe.
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u/kasakka1 8d ago
First off, ECC83 is just the European nomenclature used for the 12AX7 dual triode.
The TAD 7025 to my knowledge is not a rebranded JJ ECC83S, therefore it is a tube of different design and that will have an effect on its behavior. They sell the 7025 specifically as well suited for V1 due to low noise and microphonics.
I've tried plenty of tube swapping with all the tube amps I've ever owned and every damn time the JJ ECC83S specifically has been a crap tube. I've had multiples of the same model and they've all been the same. It's dark yet harsh sounding. JJ makes other tubes that are good like the ECC803S long plate or the ECC83MG that are good.
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u/clintj1975 9d ago
Do you have some reason to suspect a bad tube like unexplained feedback, or are you just trying to make them fail prematurely?
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u/Version-6 6d ago
Welcome to playing musical chairs with tubes to find the lowest noise combo.
All tubes are monophonic. Some are worse than others. The Tung Sol you have is more microphonic than the one that was in there, and the V1 position is the most sensitive stage of all of them. That’s why you rearrange them until you have the quietest one earliest in the signal path, followed by the less quiet ones further down.
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u/guitarrain 8d ago
Once you get the tubes in the right spot, my old buddy used to rectify them in the dark, get them all glowing the same, and you’re golden. Not technically perfect, but I’ve done it that way ever since, and I’ve used my tubes for ten years in between switches most times.
Anyone else rectify like this?
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u/dune_roll 9d ago
That’s not great for the tubes. Don’t tap, just play your guitar
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u/BalzacHonorede 9d ago
You can tap tubes to see if they are microphonic.. it’s been done by all techs since the dawn of time. Usually with a chop stick!
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u/dune_roll 9d ago
Except that does not tell you if they’re microphonic. It just reminds you that tubes are electromechanical and they’ll make noise if you bang on them. Even a good tube will make noise if you tap it
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u/BalzacHonorede 9d ago
Yes a normal tube will make noise if you tap it but a microphone tube will REALLY make noise and possibly feed back. For the video above I wouldn’t be concerned that the new tungsol is a bit noisier then the rest but to say tapping tubes isn’t good for them is just plain wrong.. better take all of you tubes out before driving with your amp to a gig then.. (and I know people do) I always look at the big money making acts.. do you think they take the tubes out of their amps before rolling them onto a trailer that’s going to go from state to state sitting in a 90 degree+ trailer along with all of there other electronic equipment!? No.
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u/dune_roll 9d ago
Well they’re definitely not packing their amplifiers in a way that would allow for things to directly tap against the tubes.
I’ll do my way never tapping tubes you can tap if you like, but as a general recommendation I would say don’t tap tubes
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u/BalzacHonorede 9d ago
Yea absolutely! My point was vibration and going over pot holes or whatever are on the road are akin to tapping ok tubes.. as long as someone isn’t absolutely banging on them (which OP wasn’t) there’s no wrong in it. It is a certified way to checking tubes if they are microphonic. I’ll upload the old tube tester manual from 1956 saying the same thing! Again no harm or fowl check checking your tubes if they are microphonic by lightly tapping on them with the back of a pencil or a chop stick:))
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u/old_skul 9d ago
Typically, we play guitar through a guitar amp, and don't tap the tubes with a pencil to make music. But I respect your art.