Class D is just Dandy!

Hello Ralph,

The noise is a bit difficult to describe. It's similar to a 60 cycle hum, with a sort of "buzz" in addition to the hum. Strangely, when my home theater setup is on (Comcast DVR, Primare SP 31 HT processor, Sony HDL display), when making changes on the Comcast remote, the noise abates momentarily during the sequence of time the button is being pushed. I know this sounds far-fetched, but it happens. 

Erik, Ralph, I appreciate your responses, thank you.

Regards,
Dan

...when my home theater setup is on (Comcast DVR, Primare SP 31 HT processor, Sony HDL display), when making changes on the Comcast remote, the noise abates momentarily during the sequence of time the button is being pushed.

Hi Dan,

That’s certainly an interesting finding. Perhaps the DVR is the root cause of the noise, possibly even when it is turned off and most (but presumably not all) of its circuitry is unpowered. If you already haven’t, you might try disconnecting it and pulling the plug on it. Also, does the remote communicate with it optically, or via RF? If the latter, you might try removing its batteries.

Best regards,
-- Al

Hello Al,

To shed a bit more light on the subject, and I don't know in what way it may effect your idea of the issue, but when the Class amp is out of service, and my SET 300 B amp is in use, there is no issue with noise. Even when my HT system is in use with the SET amp (I use a separate tube preamp that the front two channels are connected to, including having the processor stereo cables run to the two channel preamplifier).

So, my thinking is the noise emanates from the Class D amp, not from the cable box or processor.

Thanks again regards,
Dan 

Thanks for the additional info, Dan. But if I understand correctly it still leaves open the possibility that the DVR or its remote may be the source of the noise, as it would seem conceivable that the class D amps may simply be more sensitive to pickup of electrical noise that is present in their environment than the SET amp. Perhaps as a result of wider bandwidth, or differences in gain (which is typically higher for class D amps than for SET amps), or any of the many other differences that may exist between the two designs.

Obviously what I was speculating is a somewhat wild guess, but it was prompted by your mention of the effects of the DVR’s remote.

Best regards,
-- Al

@islandmandan , I'm with Al on this one. The amp should be fine with no input connected, go ahead and disconnect  the input and see if you still have that noise. If so => amplifier, if not => input