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Mechanical Hum from Class A Amplifier Clayton

Hi All,

Need some advise,

I have a paid of Clayton M300 Monos,

Speakers Tested on were Danley SH50 Horn 100db and Legacy Audio Whisper XD 94db

I noticed one of the mono block has a louder Mechanical Hum and tends to get hotter. The amps are giving off a Hiss sound with some mechanical buzz noise in the midrange drivers.

The other mono block has hiss and slight hum with a much lower Mechnical buzz from the amplifier. What concerns me is the Hiss noise. Its not only a hiss but some buzz mixed into it.

I tried connecting the amps directly to the wall socket and to a AC Regenerator and nothing seems to sort the issue out. Is this normal noise for a Class A amplifier to make a loud hissing noise? My Tube amps have a lower noise floor specially the Bob Carver which are dead silent, The ATI amplifier is Also Dead Silent.
dragon_vibe
georgehifi's avatar
georgehifi
10,312 posts
 
If the Class A bias is higher on one amp it will be hotter, and if it is bias higher than the specs then it will stress the transformer and cause it to hum.
It needs to be looked at, do not play it. I have seen a transformer damaged because the bias was too high.

Cheers George
dragon_vibe OP
430 posts
 
I have removed them and they going back to Wilson, The Midrange from the mono amp is distorting.
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Good luck, let us know how you make out.
dragon_vibe OP
430 posts
 
Getting a Refund, This unit was sent back to Wilson for repair as the first time it was noisy and the sound was distorted. Came back and still got problems. Not taking the risk again. Already spent thousands of dollars on shipping, Tax and Agent Fees. Going down another route. Possibly MSB 203 Mono Blocks.
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
That is a shame, though I can not blame you, I know what a hassle it can become. As I posted earlier, I gave up on my M-100 monoblock amps too for transformer hum. These are great sounding amps when the music was playing, but that constant hum during quiet passages eventually drove me to sell them.

Many folks don't have issues with these amps, so they just seem to be very sensitive towards the electrical lines, which is very unusual for solid state designs. I've had issues like this before with tube equipment, but outside of Clayton Audio, I have never had issues like this from solid state designs.
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