Loud humming coming from one BHK 300 mono at start-up

Please do contact our service department. It’s likely something simple.

Will do, thanks Paul.

Well…BHK 300 is in the possession of PS Audio. Very interested to see what the issue is.

Hopefully I will have repaired or replaced monoblock by the end of next week.

What’s driving your Focals now? Or are they having a little break?

Taking a nap. : )

I’ll be very interested to know what the root cause is. I don’t have a mechanical noise problem with any gear in my current rig, but have in the past. It’s not that uncommon. Keep those updates coming, friend. :slight_smile:

Yes. Please follow up with the diagnosis etc.

Egads that sounds nasty. Are the amps plugged into the same circuit?

Same P15, actually.

I suspect this is not related to the power transformer.
The BHK starts drawing more current as soon as the power button is pressed, not 30 seconds afterwards.
The noise in the video sounds moe like a chattering mute relay to me.

The noise starts as soon as the amp is turned on, and gets much louder once the tubes have warmed up and the amp clicks on in operating mode. After the amp comes up to temp (10-15 minutes), the sound disappears. I hope to hear something from PS Audio today.

See watchdogs thread …

Not sure I follow.

My issue was a bad input board that they replaced…and supposedly all is good now. The amp is on the way back to me…will confirm upon receipt.

I look forward to the update.

Well if you read the first paragraph - he says he got a new input board… thought that might be of interest

What thread? Link?

It’s here:

:). Thanks.

Thanks Watchdog and Timm!

Watchdog, why did you send both amps in when you were only hearing the buzz in one amp? Never mind…I got confused with “The BHK’s are back” title.

The local distributor wanted to send both as a matter of thoroughness. PSAudio decided to revisit the cranky amp only.