2. amps-preamps
  3. 1061393832

Help Troubleshoot - Left Ch. Louder than Right Ch.

I need your collective troubleshooting assistance.

I just put together a new system (comprised of used gear, of course) and hooked it all up last night.

Unfortunately, the left channel is considerably louder than the right. Or - it could be that the right is much QUIETER than the left. Not to be facetious, but in actuality, the left channel seems more "appropriate" all things considered.

The amp is an Antique Sound Labs AQ-1002 (50wpc) and the preamp is a Counterpoint SA-1000. Unfortunately, I don't have any additional components to swap out and determine which piece is the culprit. Can you guys think of any other techniques that might help determine what's causing the problem?

Also, if the amp is not biased properly, could that cause one channel to play louder (or quieter) than the other? There are no Gain controls on the amp that I can see.

I need to figure out what's wrong so that I can either fix it, or seek recourse from the seller before too much time has elapsed.

Thanks guys!
gullahisland

Showing 5 responses by gullahisland

gullahisland OP
83 posts
 
Newbee - Please forgive my ignorance, but I assume by "drive tubes", that means the 6550 output tubes? On the input side there are 4 12AU7s.

Thanks again everybody.
gullahisland OP
83 posts
 
A quick update:

I went home for lunch today and tried swapping the placement of the the 12AU7s and an interesting thing happened. The balance now seems normal. I also listened closely for distortion or other signs that the tube(s) are failing and couldn't really tell.

My kids were taking a nap, so I couldn't really "listen", but as best I could tell, the problem seems to have gone away.

Now I'm more baffled than ever. Could one of them have just been loose? Is it possible that one of them is failing and the problem will be intermittent until it finally goes out?

This raises another question. I hear about people "testing" their tubes. Where could I take them to find out if they're any good or not? I don't want to just replace them all if I don't have to. It's not a huge investment, but I'd be looking at around $150-175 to re-tube the amp.

Are there any places in the SF Bay Area that will test your tubes for you and or sell new ones?

Thanks so much!
gullahisland OP
83 posts
 
Jeff, you're a genius!

I'll give that a try this evening and report back tomorrow.

If it turns out to be the amp...Does anyone have an idea of what might cause such a thing? Could it be as simple as the bias?

Thanks!
gullahisland OP
83 posts
 
Well,

I switched the interconnects and the problem stays in the right channel. I switched the speakers as well, just to confirm that there's not issue with them and, again, the problem stays in the right channel.

Marakanetz - Should I just switch the placement of the tubes and see if the problem follows the tubes? The amp uses two 6550s for each channel. Is it safe to just switch them? I'm a tube novice and don't want to do anything catastrophic.

Thanks again.
gullahisland OP
83 posts
 
Thanks everybody. I'm guessing that Newbee is right. All I know is that after swapping the placement of the input tubes, it sounds spectacular.

I couldn't be happier and I sure appreciate the assistance.

Good listening!
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