Channel tracking problem Rotel RA-931 MK 2 amp?


New member
Username: Crapstanzo

Post Number: 1
Registered: Jul-08
Hi there,

for about 7 years now I've been the happy owner of a Rotel RA-931 MK 2 amplifier. Recently I started noticing a slight problem while using the amp at (very) low volume levels. The problem is that near the very lower end of the volume range the volume of the left channel decreases more rapidly than the volume of the right channel. At *very* low volumes the left channel is completely quiet (which means I also cannot correct it using the balance control). It doesn't matter whether I'm listening through my speakers or using headphones; the problem occurs in both cases (also it doesn't matter whether I'm connecting my speakers as 'direct' or 'remote' ones).

(Incidentally, while listening through headphones I can still hear *some* sound even if the volume is completely down to zero).

Also, since I've recently replaced my speaker cables I can safely rule that out as a cause as well (the problem was already there before I did this) .

My initial suspicion was that the problem might be related to dust that may have entered the volume control switch. However, a Google search led me to this forum post:

which actually looks pretty similar to my problem.

From my description above, could anyone perhaps give me some suggestions as to the cause and possible solution of this problem? If it's a matter of dust, would blowing out the volume control with compressed air make any sense at all?

Another option I'm considering is placing an in-line attenuator between my CD player and my amp. However, I've read some stories of people experiencing dull or lifeless sound with these devices, so I'd first like to consider the other options ...

Any thoughts or suggestions on this would be much appreciated!

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 12810
Registered: May-04

The vc on your Rotel is sealed and dust cannot enter. The traces are possibly oxidized from the presence of air within the sealed pot. You cannot blow this out with compressed air. You can try a cleaner such as "DeOxit" or "ProGold" if you can find a break in the casing around the pot. Other wise, it would be best to take the unit to a repair facility and let the tech do a complete clean and service on your amplifier. It's worth the money and the Rotel will sound better afterwards.

"However, I've read some stories of people experiencing dull or lifeless sound with these devices, so I'd first like to consider the other options ... "

What other options? Why do you want an attenutator? To solve the vc problem? That's painting the house in hopes the foundation won't shift.


New member
Username: Crapstanzo

Post Number: 2
Registered: Jul-08
Hi Jan,

thanks for your reply. Hadn't thought of those oxidized traces myself, that's really useful to know. Also I agree with you that in that case there's not much of a point in getting an attenuator

I'll try to find a decent repair facility. I can also see a fair bit of dust that has accumulated inside the unit, so a complete clean and service is probably a good idea anyway.

Many thanks again for your comments, this is exactly what I was looking for!



Platinum Member
Username: Nuck

Post Number: 10541
Registered: Dec-04
Johan, that is a quality unit.
Your service investment will be worth it.
You can do it yourself if so inclined.

New member
Username: Crapstanzo

Post Number: 3
Registered: Jul-08
OK, I just phoned the shop where I originally bought my Rotel and it turns out they also do repairs and maintenance, so I'll pop round there one of these days for a full service and cleaning job.
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