Your source equipment could also be the cause. Also, the loudspeaker.(Depends on how close of a tolerance the manufacturer used w/ the drivers.)
12 responses Add your response
Try swapping the left and right input cables on the back of your amp ( power it down first)
Then listen and see if the louder sound is on the same speaker or if it moved.
If the other channel is now louder the problem is in your preamp or before. IF the same channel is louder it's in the amp or speaker
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.
I have a transient problem with my VTL 185s that sounds kind of similar and i was wondering if this could be a tube thing as well. One amp will suddenly get louder and then start to hum, or will just start to hum without the volume surge. Toggling the on off switch gets rid of it...no need to let the sound die, just hit the switch. same problem with different ic's and in two different houses. Used to be i could toggle either power amp or the pre amp and the hum would quit but now seems to only work on the afflicted amp. doesn't happen often enough to spend the money to ship it to VTL, where it would probaly work fine. any ideas?
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!