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Post by indiehouse on Apr 30, 2015 21:35:51 GMT -6
It just seems weird, though, that BOTH the 5749's as well as the 6836 would be microphonic.
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Post by Johnkenn on Apr 30, 2015 21:42:45 GMT -6
Hmmm...weird. Thought about sending it in?
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Post by Martin John Butler on Apr 30, 2015 22:28:37 GMT -6
The Sta lines sound terribly wooly, something is definitely wrong. Good luck, listen to cowboy and Randy, they know what they're talking about.
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Post by Johnkenn on Apr 30, 2015 23:08:24 GMT -6
Yeah, don't listen to me...
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Post by indiehouse on May 1, 2015 4:27:07 GMT -6
Hmmm...weird. Thought about sending it in? Yeah, that's the next step. I think I'm gonna order more tubes today, and if that doesn't work, I'm gonna have to pony up some shipping dough. I hate the thought of paying all that round trip shipping costs and it ends up being a $7 tube. So, we'll see. |
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Post by kcatthedog on May 1, 2015 5:42:35 GMT -6
I have got to admit I find this tube thing with the sta weird I have read three posts by people here with sta's and they have all had tube problems ?
Once in normal operating procedures tubes should last a long time, with respec,t has any body asked if there was a bad lot of tubes ?
The sta is a high quality product. Something seems strange ?
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Post by EmRR on May 1, 2015 9:49:49 GMT -6
Did you address the items in my earlier post? I don't see a comment.
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Post by Johnkenn on May 1, 2015 11:05:55 GMT -6
Is the current balance control for the 6V6's properly adjusted? I think there's a balance control for the 6BJ6's too (if that's your GR tube), maybe you have a 6386 in there? Pull the 6AL5 and see how it sounds as a straight amplifier, no compression. If your input and output controls have been parked at the same setting for a long time, exercise them to see that they self-clean. I wasn't aware the 6BJ6's had a balance control. |
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Post by indiehouse on May 1, 2015 11:27:12 GMT -6
Is the current balance control for the 6V6's properly adjusted? I think there's a balance control for the 6BJ6's too (if that's your GR tube), maybe you have a 6386 in there? Pull the 6AL5 and see how it sounds as a straight amplifier, no compression. If your input and output controls have been parked at the same setting for a long time, exercise them to see that they self-clean. Did you address the items in my earlier post? I don't see a comment. Sorry for not responding sooner. I tried out your suggestions last night. I have balanced the 6V6's by holding the red button down and adjusting the control pot until the hum is at it's lowest. I had the 5749/6BJ6's in, and tried adjusting the trim pot (I assume the red button is only for the power balance, right?), but could not hear a noticeable difference in the noise floor. In effect, that trim pot didn't seem to do anything. Next, I removed the 5749's and inserted the 6386 and tried adjusting the trim pot with the same results. No difference. Both the 5749's and the 6386 are really microphonic. Phil said these tubes will be microphonic to some degree, but should be 40db below operating level. I guess, but I'm telling you it's really noticeable to me. I pulled the 6AL5 and it does seem to sound a bit clearer. I went ahead and ordered a couple of pairs of 5749's (in order to choose the pair with the least amount of noise since I can't have them tested for noise beforehand), a 6AL5 and a 0B2 tube. I'm just replacing the whole lot. I might even have another rectifier tube as well. If this doesn't work, then I have no idea what to do. |
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Post by indiehouse on May 1, 2015 11:39:10 GMT -6
FYI, I've spent $90 total on replacement tubes (including shipping on 3 different occasions), to replace every tube except for the 5Y3. I think Retro is asking $165 for a set, though maybe they get more rigorous testing than what I got.
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Post by dandeurloo on May 1, 2015 13:35:12 GMT -6
Dude, email Bowie. He has is the real deal tube guy, plus he owns a Sta Level. He will fix you up.
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Post by EmRR on May 2, 2015 8:33:18 GMT -6
The 5749's and 6386's will be microphonic if tapped, no doubt. They are the first tube, with the most post gain applied. Totally normal, without being there to hear your unit in person. I'd be worried if I heard it while flipping the power switch in adjacent equipment/etc, not really otherwise.
I've only worked on Gates Sta-Levels in the past. I don't have a Retro in front of me, nor do I see any documentation on their site for the 6V6 and 6BA6 adjustments, there may be something different in the arrangement. If you've done them by the book, then you can at least take those adjustments off the list. Even if there was test equipment needed you don't possess, your ears would have told you something.
I've seen the 6AL5 be the whole problem on several occasions. Even without gain reduction, and they can look fine on a tube tester.
Hopefully the other tubes will fix you up.
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