Buzz Hum Aleph 5 with computer as source, no good results with GLI

[zigo3]

Hello
I use computer as source with RME digi 96/8.
When I connect the analog output to my Pass Labs Aleph 5, when it begins be warm, appears a buzz on both channels, when it's cold nothing.
I tried with a Melos triode 200+ (200 wpc class A/B tubes) the same problem.
With NAD 3020i , Hypex 400, Hypex 180 , Trends TA10.1, (maybe I forget other...) , nothing.

I put a ground loop isolator and the buzz is a little attenuates, but remain.

I tried using the RME digital output (toslink or coaxial) with a Constantine DAC and the buzz becomes a kind of "wave" that don't attenuate neither with the ground loop isolator between the DAC and the powamp.

Somebody have suggestions?
And why with this 2 poweramps and not with other?

Thanks in advance

 

[Iain McNeill]

Do the amps all have the same gain? Maybe the big power amps got more gain, making the noise floor louder?

I had to pad one amp way down to get hum/hiss acceptable. It was still plenty loud!

 

[vitalstates]

Hi Zigo

I had a very similar problem with my studio set up when using my layla 3g. I found buzz when feeding my EL34 or my F4 with analaog outs(pseudo balanced) but no buzz when feeding my aura integrated with analog outs.

I got round the problem by putting Lite DAC-AH between layla and EL34, using layla digital out. No buzz at all and the best sound I have got.

I guessed that the aura didn't show buzz because of the volume pot...perhaps if I turned the volume pot all the way up it would mimic the EL34 connection and might buzz. I use the digital volume in this machine, in all cases.

just a couple of thoughts, but it might be worth investigating the digital out a bit further because that should remove any ground loop probs you might have(use toslink obviously).

Ed

 

[zigo3]

Do the amps all have the same gain? Maybe the big power amps got more gain, making the noise floor louder?

I had to pad one amp way down to get hum/hiss acceptable. It was still plenty loud!

Hi Zigo

I had a very similar problem with my studio set up when using my layla 3g. I found buzz when feeding my EL34 or my F4 with analaog outs(pseudo balanced) but no buzz when feeding my aura integrated with analog outs.

I got round the problem by putting Lite DAC-AH between layla and EL34, using layla digital out. No buzz at all and the best sound I have got.

I guessed that the aura didn't show buzz because of the volume pot...perhaps if I turned the volume pot all the way up it would mimic the EL34 connection and might buzz. I use the digital volume in this machine, in all cases.

just a couple of thoughts, but it might be worth investigating the digital out a bit further because that should remove any ground loop probs you might have(use toslink obviously).

Ed

Thankyou very much for your suggestions.
About the volume, I had no problem feeding directly the Hypex400 (200 wpc powamp),Hypex180 (100 wpc powamp) and using NAD 3020 as powamp. Using it as pre and feeding both Melos and Aleph the buzz grown up...mystery...

About DAC-AH (or maybe other DACs too) it could be an idea: maybe the DACs filter in some way the signal. I tried Constantine and the hum was really attenuate, it becomes a kind of "wave", like those old radios.

I tried other trics (before my Melos http://www.diyaudio.com/forums/showthread.php?s=&threadid=113066 and Aleph http://www.diyaudio.com/forums/showthread.php?s=&threadid=117734 burned ) and the last ones took good attenuation, like put all the power imput cables on the same multi outlet or use good shielded power cables or try to isolate more as possible the signal cable between computer and pre or powamp, and I seen good attenuates results. The hum was not disappeared, but did'nt compromise the listen.
I tried other, like isolate more as possible the sound card, change the signal cables with shielded cables, disconnect the computer devices, but did'nt take results.