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Gamut D200 Mrk II hum/buzz issue

Hello all, quick question to those with these types of amps (mrkII or III...heck or even mrk I for that matter)

Does your amp make a slight bzzz when no sources are connected/on/muted? I have gone through every check and I know for sure it is not:
1 - grounding issue
2 - pre issue
3 - cable issue
4 - power issue
5 - underpants gnomes issue...(dont ask)

I dont have super sensitive speakers either...only acoustic zen adagios (88 db)...maggies MMG (86 db i think)...JBL 4312C monitors (91 db) and my theil 2.4 (88-89 db). I hear this noise on the Zens and the JBLs and the Theils..but not the maggies (I think that the planar design helps possibly mask the noise..?) Anyway...I got to the point where I had absolutely NOTHING connected to the amps except the speakers...and still could hear the noise. The buzz/hum DOES NOT get louder when the volume is turned up. Does anyone else have this issue with their d200's? I have cheaper equipment that is dead silent...even tube...any help would be appreciated.

Thanks

Spiro
aptquark
7 responses Add your response
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drubin
3,274 posts
 
My D200 Mk2 is dead silent through the speakers, but has a mechanical hum/buzz (exactly how I describe it) when connected to a PS Audio Power Plant Premier. To be clear, the noise emanates from the amp chassis.
aptquark OP
99 posts
 
I was reading you post earlier Drubin...thank you for your time. Unfortunately for me, its not mechanical...the damn noise comes out of the speaker. Its not very loud...but annoying when you know it should not be there.
nico_g
35 posts
 
Hello,
I have a D200 mkIII and no noise with my speakers that are sensitives : 95db/w/m (Tannoy GRF).
But you should check the gain setting of your amp. On GamuT amps you can set the gain between around 20db and 35 db. The default setting is high : aver 30db, if I remember.
You can test with a lower gain, like me : I use the lowest gain in my system.
In order to modify the gain, you have to remove the top plate of the amp and select with some little switches (two by side, located on the top of the power circuitboards).
Best Regards
aptquark OP
99 posts
 
Unfortunately I have tried that also. I was told that you can access the switches with a toothpick instead of removing the top btw. Thanks for your time.
casouza
239 posts
 
It is pretty normal for any high-powered unbalanced (RCA input)amplifier to hum if nothing is connected to its inputs.

To be certain, short one end of a pair of RCA cables with paper clips, telephone wire, a piece of solder, whatever is handy and conductive, insert the other end of the IC on the amp's input connectors and turn the amp on.
By short I mean connect the center plug to the outer collar of the RCA plug. Better still, buy a pair of inexpensive RCA plugs from RS and sloder pluas and minus together.
This will NOT damage any RCA input amp or preamp.
I bet the hum will disappear.
BTW I used to own a MKII, great amp.
aptquark OP
99 posts
 
It actually has balanced inputs...thats what I primarily use for connection. But I havnt tried the shorting of the IC's. I have also tried using a power cord that has no ground connection. No change. Thank you for your suggestion.
gray_hound
6 posts
 
I have the same exact issue with my adcom 5500 and my ps audio power plant premier. Speakers sound great. Chassis is humming. I believe it is actually the transformer.
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