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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
mitch2
4,008 posts
 
Good points Timrhu, my speakers are only 90dB sensitive and need the high power to drive less than 4 ohms impedence at lower frequencies - I missed how sensitive the partnering speakers are. While these are great sounding amps in my system, Clayton makes smaller amps that may work better with such sensitive speakers. Regarding temp., here is a link to an interesting post where someone measured their heat sink temperature over time to document how long it took a pair of these amps to achieve full operating temperature
http://www.audiocircle.com/index.php?topic=101551.msg1026780#msg1026780
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
I owned a pair of M-100's a few years ago and thought they sounded excellent when playing music. However, they had a mechanical buzz coming from transformer hum that I never could get rid of, no matter what I tried. Changing cables and cords didn't help, even a PS Audio Humbuster did not work. I eventually gave up and sold them.

If one of your monoblocks is running hotter though, it sounds as if the bias needs to be adjusted too. I would send them back to Wilson Shen to see if he could solve your issues. Good luck.
dragon_vibe OP
430 posts
 
I stressed the amplifier todays and they keep cutting off at some point, something don't seem right, My Bobs and ATI drive them at insane levels yet the claytons are cutting out when the volume bar is up at 48. The bobs pass 60 easily at points my ears cant handle them and the speakers are dynamic. Even testing on the Danley the Amps just drop out signals. Both are behaving this way I assume the power designed for the 220-240 voltage is not ready yet.
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.
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