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Post by Johnkenn on Dec 17, 2017 21:09:24 GMT -6
Was starting to get some crackling in the audio path and tracked it down to one of the 6V6s in the Sta. EmRR do you happen to know which tubes most greatly contribute to the tone of the unit? The 6386 is the gain reduction tube, right? I was thinking about spending a little more and buying NOS 6V6s...just not sure how much they contribute to the tone? Pardon my ignorance on the subject. |
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Post by EmRR on Dec 17, 2017 21:17:57 GMT -6
6386/12AT7/6V6 predominately, but one could say they all contribute to the sound. Crackling doesn't sound specifically like a tube problem, how did you track that down? Sometimes it can be contact resistance in the socket, and pulling a tube out and putting it back can clear it up. I have seen a lot of funky 6AL5's in tube comps cause distortion, yet look fine on a tube tester. 6V6's need to be matched for current draw, which is a lot harder with NOS. I don't use NOS for 6V6/6L6/etc for that reason, unless I can match them out of a bucket of used ones I have.
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Post by c0rtland on Dec 17, 2017 21:18:21 GMT -6
I'll be reading this thread. Good question. I really wish I went to electrical engineering school instead of sound engineering school.
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Post by Johnkenn on Dec 18, 2017 15:36:16 GMT -6
Tapping on each tube with a pencil...and that was the one that was doing it. Is that a microphonic tube?
I was reading where some said the Tung Sol 6V6s were a little darker? Have any experience with those?
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Post by EmRR on Dec 18, 2017 22:18:18 GMT -6
Good god, these snowflakes here and at the purple place are hammering the crap out of my CPU, like 200%on an i7, fan revved up. Weird.
Microphonics wouldn't really be a crackling noise normally. Same crackling while you are using it I assume? It may be going bad, it's hard to say. Swap the 6V6's around and see if the behavior follows. I don't think I've used the new Tung Sol.
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Post by Coil Audio on Dec 18, 2017 23:10:59 GMT -6
What Doug said - but also try pulling and re-seating it - certain sockets are prone to corrosion, even over a short period of time.
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Post by Johnkenn on Dec 20, 2017 17:51:11 GMT -6
Good god, these snowflakes here and at the purple place are hammering the crap out of my CPU, like 200%on an i7, fan revved up. Weird. Microphonics wouldn't really be a crackling noise normally. Same crackling while you are using it I assume? It may be going bad, it's hard to say. Swap the 6V6's around and see if the behavior follows. I don't think I've used the new Tung Sol. It cleared up. Doesn’t look like it’s going to snow again. |
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Post by Johnkenn on Dec 20, 2017 17:52:16 GMT -6
What Doug said - but also try pulling and re-seating it - certain sockets are prone to corrosion, even over a short period of time. You guys think there’s any need for nos power tube replacement? |
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Post by EmRR on Dec 20, 2017 17:55:09 GMT -6
I like snow, just not in the house....
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Post by Guitar on Dec 20, 2017 18:01:03 GMT -6
I like snow, just not in the house.... It was giving me a headache... seems to have cleared up |
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Post by Coil Audio on Dec 21, 2017 15:39:23 GMT -6
What Doug said - but also try pulling and re-seating it - certain sockets are prone to corrosion, even over a short period of time. You guys think there’s any need for nos power tube replacement? What was in there? JJ's? You can probably get something *gulp* newer from TAD or Mullard for around $20ea that might improve the tone a few % (builds vary) - some nos mil spec Vt-107s might be a little bit more but not much - $30ea maybe? But like Doug said- prob not worth the trouble. Id say its worth having a few around to try and see what jives though - |
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Post by Martin John Butler on Dec 21, 2017 15:50:57 GMT -6
I had an amp that allowed tube changes without rebiasing. I bought a bunch of pricey NOS tubes, and discovered the new JJ's sounded better than all of the NOS tubes, including the $100 ones. So, with tubes, it's difficult to know what to get until you try them.
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Post by EmRR on Dec 21, 2017 16:19:35 GMT -6
I had an amp that allowed tube changes without rebiasing. I bought a bunch of pricey NOS tubes, and discovered the new JJ's sounded better than all of the NOS tubes, including the $100 ones. So, with tubes, it's difficult to know what to get until you try them. Especially with guitar amps, it depends very much on what the designer was working with. Sta is a cathode biased output stage, so no rebias to do, but matching for current balance is important. Wildly different current draw will overall raise or lower voltage on the other 2 tubes. There's a voltage regulator tube, but it's more about regulating the threshold voltage than the tube voltages. |
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Post by Martin John Butler on Dec 21, 2017 16:42:43 GMT -6
uhh.. what EmRR said ;-)
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Post by carival on Dec 22, 2017 10:01:13 GMT -6
crackling and sputtering in my Gates Sta Level ended up being a 6v6 tube socket. Is the crackling independent of input and output settings? I have a spot on my output pot (the spot where I always want it to be, haha) that is sometimes crackly, even after cleaning. Some day I'll replace it. I always closely match output tubes. Mostly old stock, but the new JJ 6v6s I've gotten from Euro Tube (I think) are very closely matched and sound pretty good in many circuits. The RCA gray plate 6v6s have been used almost daily in my Sta Level for 20 years.
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