Vandersteen not so vonderful

[Peter S]

Hi Folks;
This plate amplifier has me perplexed. There is 120 Hz buzz on the speaker output (low level) but audible. I don't have a schematic for this model V2W but maybe this is a simple problem?
The buzz on the speaker seems to be present on one power supply rail. I have straddled the noisy side with another 6800 ufd cap with no effect. First image is the speaker output;

 

[Peter S]

Here are the power supply rails. As mentioned, the 'bad' side was paralleled with 6800 ufd cap and a 20 ufd 250 V Mylar (or polester, not sure, one of those yellow jobs) with no effect. This amp is trying to tell me something. There is also about 350 mV of DC offset on the speaker output....help!!

 

[AVWERK]

Send the plate amp to Richard if your unsuccessful

 

[Capt Grogg]

PM sent

 

[Peter S]

Hi Folks;
Just an update; Thanks G and everyone at diyaudio. I was instructed to connect the 'FB' terminal to the speaker 'Out' terminal. All good now, the amp is quiet!