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Speaker buzz with SS amplifier, input disconnected

If a buzz/hum is present from my loudspeakers with solid state Monoblock inputs disconnected, what are the likely possibilities accounting for the buzz. Do toroidal transformers ever transmit transformer noise to the loudspeakers?
I thought ground loops were more or less eliminated with amplifier inputs disconnected. Buzz/hum is present in both loudspeakers(with inputs disconnected), more pronounced in one. Thank you for your suggestions!

Amplifier. Gamut M250
Speaker. KEF Blade
audiobrian
audiobrian OP
186 posts
 
The noise through my Blades is unchanged with inputs connected or disconnected to the Gamut monoblocks. It is more of a buzz than hum, and is audible about 3 ft from loudspeakers. Speakers are not biamped and noise persists when plugged into power conditioner, DC Blocker or
cheater plug used. Can an amplifier itself transmit buzz into a loudspeaker?
Gamut claims it must be dirty AC, but I don't believe this to be the case?
When I use my tube amplifier, no hum or buzz evident.
Thanks again to to those responding.
Brian
Post removed 
atmasphere's avatar
atmasphere
12,128 posts
 
This sounds like an internal layout problem to me. It is true however that with an open input (nothing connected) that there will be a greater amount of noise present. But that should be gone with your preamp connected.

Now one exception may be that your interconnect cable is responsible for some of the buzz. So it is a good idea to try a different cable before blaming the amp!
audiobrian OP
186 posts
 
Thanks Attmasphere/RK
I've tried a couple of interconnects without change. I believe you are right about an internal layout problem. Both monoblocks buzz through the loudspeakers, one louder than the other, inputs either connected or not.
Would you kindly expound on the type of layout problem which might result in this speaker buzz. Can a noisy toroid transmit buzz to loudspeakers etc
I know most talk of noisy transformers in the chassis without transmission to loudspeakers.
Many thanks for your response!
tom32
33 posts
 

Like Arh is asking above, is this a really bad hum/noise or is this just the tiny hum you might get from a floating input?

When 60 Hz hum becomes really bad, it can create a buzzing hum. The 60 Hz wave is so strong that it clips off at the peaks and creates many new frequencies that are higher order harmonics of 60 (120, 240, 480, 960 Hz, etc.).

If this is a pretty loud hum, then it sounds like you have either had a big electrolytic cap in the power supply going bad, or there is a short in the amp that is so bad it is bleeding the power supply down. If it is an internal short, then it will smell bad and be overheating. If it is just an electrolytic filter cap, it might slightly smell acidic, but won't be overheating that bad.

Anyway, sounds like she needs an overhaul.
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