VO-BB - 20 YEARS OLD!

[chrisvoco]

Nobody will probably believe me, but the proof turned out to be in the pudding. Or in the amplifier, in this case. I just have to share this somewhere, so here goes.

I noticed that my dry voice tracks frequently have a "chunky" quality to them. Not a desirable chunky. For a period of many late nights, I went through the standard motions of plugging, unplugging, rearranging, scoping, measuring, without being able to reliably make the problem go away. The sound - a subtle distortion that made my audio sound slightly wrong - was present regardless of which of my three mics I used. I figured maybe it was just my voice, and I'd have to live with it.

Tonight, I found the answer. I fell back to trying to track down the problem, got fed up with messing with it, and went upstairs to get a drink. I had turned off the amplifier (Technics, not ancient, but not new) and was monitoring through cans.

So, I spent a few minutes upstairs, then came back down, put on my cans, and talked and... suddenly my nice new German mic sounded like a nice new German mic!

I then didn't drink anything else and talked myself dry just to be sure it really wasn't me. And then I *turned back on* the amp.

After a few minutes of heating back up, the chunky quality reappeared.

So I turned the amp off again, and resumed monitoring through phones. Disconnected the amp from the chain altogether, and haven't had any chunky since.

And no, my cabling ain't the problem.

Betcha if I run a sine wave in and then go along with the scope at each stage of the amplifier, I'll find a place where suddenly the nice smooth peaks are flattened. Bad cap.

What I can't immediately figure out is how this is causing a problem in the other direction, on the other end of the audio chain, in a nice Focusrite interface - the distortion was actually *getting in to the recorded audio*.

The easy answer, of course, is to ditch my elderly amp and buy a new one.

But I have a giant drawer full of capacitors in the other room...
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Finally, Ford stops starting to say things and starts.

[Frank F]

What pre is it? What mic is it you are using? Is this "sound" consistent over time or does it diminish after a short period of bad audio? Do you know if the resistors are metal or electrolytic? Are the caps metal or not? What sound card are you using? How are you connected to the sound card (XLR, 1/4", etc.)? How is heh preamp stored when not in use. Do you have consistent high or low humidity? Have you tried putting the preamp in the freezer over night, pulling it out and seeing if the aberration returns and how long it takes for this to occur?

OK this is just a short list of questions I would need to know to even venture a guess as to the problem.

Now a final few questions... can you do the repairs yourself? Do you know how to read a schematic? Solder? Do you know how to handle tantalum caps?

If you are unable to answer any of the above questions; get yourself a new preamp. Or at least one you can borrow for a few days. Then try the new or new to you preamp in the chain. If the sound is stable, you know it is the preamp. If not, the problem exists somewhere else in the microphone chain.

You may be simply over-driving the sound cards in/out's, or it may be something else all together. Do not throw out the baby with the bath water quite yet.

Frank F
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Be thankful for the bad things in life. They opened your eyes to the good things you weren't paying attention to before. email: thevoice@usa.com

[chrisvoco]

Thanks, but this is more of a "holy cow, can you believe this" than a question.

Should've been more specific - not my preamp, but the crummy bookshelf amp driving my speakers.
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Finally, Ford stops starting to say things and starts.

[Ed Fisher]

Get ye some nice self-powered monitors and go forth and prosper.
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"I reserve the right to be completely wrong."

[chrisvoco]

I've thought about that, but can't decide if it's really the best thing for me. The main drawback to that is I already have two sets of speakers I really like - one set at the desk for editing and general listening, and the other in position for working at the keyboard on music. I suppose the answer would be to buy *two* sets of powered monitors.

Lemme go ask my wife...

(everybody funny; now you funny, too!)
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Finally, Ford stops starting to say things and starts.