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12AX7's
Jun 17, 2022 18:30:42 GMT -5
Post by cedarchoper58 on Jun 17, 2022 18:30:42 GMT -5
why is there such a huge difference in sound from one to another. My pro reverb i have a JAN phillips and it sounds completly different if i put a JAN GE in
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12AX7's
Jun 17, 2022 18:55:38 GMT -5
via mobile
Post by Leftee on Jun 17, 2022 18:55:38 GMT -5
It could be just be the health of those tubes.
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12AX7's
Jun 18, 2022 10:09:33 GMT -5
Post by cedarchoper58 on Jun 18, 2022 10:09:33 GMT -5
It could be just be the health of those tubes. they both test good. One is long plate (phillips) GE is short |
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12AX7's
Jun 18, 2022 10:34:31 GMT -5
via mobile
Post by Leftee on Jun 18, 2022 10:34:31 GMT -5
Such is the way with tubes.
You might want to watch that long plate if it’s in V1. They can go microphonic in a combo.
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DrKev
Wholenote
It's just a guitar, it's not rocket science.
Posts: 418
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12AX7's
Jun 21, 2022 1:52:14 GMT -5
Post by DrKev on Jun 21, 2022 1:52:14 GMT -5
I would say one of those tubes of not doing the right thing and may not be soon for this world. I would not expect healthy tubes to have much of difference, if any at all.
I say this because, I have never noticed any significant difference between tubes. I have tried to measure it and record it, and once I correct for the differences in output/gain they sound exactly the same. Even between different brand AND type preamp tubes e.g. JJ ECC83S vs Mesa 12AY7 - if I boost the input to make up for the lower gain of the AY tube, they sound identical.
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Jun 21, 2022 3:49:25 GMT -5
It could be just be the health of those tubes. they both test good. …. Testers just test certain parameters, some of which may not be relevant for us. The best test for a valve is to see how well it works in its intended application circuit. A real 12AY7 will have about half the anode resistance of a 12AX7 / ECC83, so in some circuits, even when gain differences are normalised out, the frequency response will be a bit different. With current production valves though, it’s questionable whether they truly conform to type. eg 12AY7 may just get printed on the lower gm valves, 12AX7 on the higher gm valves. |
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Post by Pinetree on Jun 21, 2022 8:47:05 GMT -5
The best tube tester is the amp it's installed in.
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12AX7's
Jun 21, 2022 10:24:17 GMT -5
via mobile
Post by Vibroluxer on Jun 21, 2022 10:24:17 GMT -5
Just as things worked out I ended up with a few lifetime supplies of old guitar tubes. Mostly 12A**s. While my ears are old and I can't speak to comparing a ton of tubes, I can still hear a difference between old RCAs and British Mullard's so I can understand how your 2 GAN tubes have a different tone.
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Post by Lesterstrat on Jun 21, 2022 10:33:25 GMT -5
Amps are tuned (for a lack of a better word) with the tube that’s going to be used in mind. I had a conversation with Greg Germino about tubes years ago when I had my Club 40. He builds each amp, or amps, with what tubes he has available at the time. If for some reason he has to change tube supplier/brand, he *might* have to make tweaks to other parts to keep the sound of a particular model consistent.
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Post by Leftee on Jun 21, 2022 10:54:02 GMT -5
I sometimes “tube roll” (that’s what the kids call it these days) but only in V1 for preamp tubes. In the rest of the preamp section I’ve found I can’t tell the difference, for the most part. Sometimes rolling the PI is fruitful. And… I don’t care if that is a “balanced” tube. It’s all about the ears.
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12AX7's
Jun 21, 2022 17:24:22 GMT -5
Post by larryguitar54 on Jun 21, 2022 17:24:22 GMT -5
The best tube tester is the amp it's installed in. That's only true if you have a reference point. My Soldano sounded 'great'...until I bought new tubes. Then I realized I had been settling for less than great for awhile. |
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Jun 22, 2022 2:58:08 GMT -5
The reference point is a good spare valve of the correct / equivalent type, for each of the valve types in the amp.
Swap that in and check if anything changes. Any significant increase in signal indicates that the original valve in that socket was probably duff, needs replacing.
If no change, remove the good spare valve and refit the valve that was previously in the socket, and move on to the next socket.
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12AX7's
Jun 27, 2022 7:30:05 GMT -5
Post by LTB on Jun 27, 2022 7:30:05 GMT -5
My favorite modern 12AX7 today is the TungSol. I used it in V1 position of a Genz Benz Streamliner 600 bass amp and resultant tone was fatter and clearer lows and smooth highs.
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