Amplifier Goes into Protect Mode Right Channel


Wanted to hear your tech thoughts on this problem. After spinning vinyl for 1-3 hours, the right channel on my solid state amplifier goes into protect mode. This repeats itself multiple times each session. I have a tube preamp and tube phono stage. Only one source - turntable. I've swapped tubes in the linestage preamp which made no difference; swapped IC cables which made no difference. The linestage tube preamp is new (one month old) but I'm beginning to think it may be a leaking cap causing the trouble. Also looking at the speaker cables as a possibility. Would that matter? Any thoughts? At the point where I'm ready to RMA the preamp for bench test. Thanks in advance.
wescoman
Hmm. For your solid state amp to go into protect mode, either it is itself broken or it is putting out a lot of power into the right channel.

Assuming the solid state amp is not broken, you should be hearing the power that it is putting out in the right channel unless that power is outside the audible range or outside your speaker's performance range. Unlikely that it is high frequency. More possible that is could be subsonic.

If so, it could be originating from your cartridge or turntable, although the turntable is less likely because it would probably affect both channels. Maybe your cartridge is going bad. How old is it?

Or it could be your phono preamp. Like something involved with RIAA equalization?

If your linestage preamp is working properly, it would transmit the subsonic signal to the solid state amp and cause it to shut down. If the linestage preamp is somehow handicapped from effective transmission of subsonic signal, then the solid state amp should keep working and not shut down.

Have you tried swapping left and right channels between the turntable and the phono preamp? How about between the phono preamp and the linestage preamp?
Probably the amp but to be sure switch the left and right speaker hook ups. If problem switches sides then switch the inputs to the amp. If problem stays in same side than it is in the amp.
I would suggest sequentially reversing the left and right IC connections at one end only, first between the linestage and amp, then between the phono and linestage. If the channel going into protect mode switches then the problem is something earlier in the chain than the cable you just reversed. If the problem stays in the right channel it is being caused by something later in the chain. One other possibility although less likely is an partial/intermittent short circuit in either the right speaker cable or the speaker itself. You can eliminate this possibility by reversing the speaker cable connections at the amp to see if the problem stays in the same channel or not. Good luck and let us know your findings.
Thanks for the great ideas. I'll give them a try and see what happens when I get the speaker cable back from Acoustic Zen. First, I'll hook up everything as it should be and then wait for the right channel to shut down. Unless AZ detected problems with the right speaker cable, the shutdown should happen again. Then, I'll begin the process to reverse cables as suggested above, one step at a time, to isolate the problem. I also plan to contact CODA today and see if they have any thoughts on the subject.
Was on another website and got some great ideas. Need to check out speaker damping. My speakers sit directly on carpet. They come with spikes but I didn't install them. Maybe I need to use them or put some marble pavers underneath them. Secondly, recommendation to use turntable shelf instead of placing on butcher block and then on dedicated wood table. Third idea deals with tonearm/cartridge resonance issues. If indeed it is subsonic frequency issues, this could get complicated.