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Hi,
I'm driving a blanced out Buffalo > Legato. When I had a unbalanced setup, everything works fine, but now there's a high frequency noise on both channels. So I think it comes from the legato.
The buffalo and the legato modules are powered by Salas' Shunts, and the noise remains if the setup is grounded or floating.
As I don't know where to start, I'm looking forward to solve this issue with your help.
Thanks
Matthias
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Lets start with pictures. :)
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So, time went by quickly, but now I've some time and the noise is buggin me enough to start here with a photo. If you need to see some details, please let me know. As you see it hasn't moved into the new location (real case). http://dl.dropbox.com/u/4612940/DAC.JPG
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No ideas how to fix it or begin to search?
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Hi Matthias,
Do you also have some pictures or scemes of the balanced connectors (XLR) and how it is connected to the amplifier?
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Ähm, to cut it short - no.
The balanced outputs go balanced into the pre amplifier. Unbalanced sounds good.
Do you think it's a grounding issue? Tried both floating and grounded legato, no difference (floating sounds a bit better, though.)
When I turn on the DAC it seems the noise first rises to its later steady level. (1-2 Minutes perhaps)
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Hi Matthias,
You got me right.
I was thinking of ground and wanted to propose a floating setup.
I struggled a lot with my setup and that worked best.
Have you tried to eliminate things here by disconnecting certain components?
(I figure you have tried evrything already)
Jordo
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Hi Jordo,
yes, I removed everything which is not necessary. Always hum but when I run it single ended (from the legato boards) everthing's fine.
I'm wondering why nobody from twisted pear has a idea...
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I am very sorry but I don't think I can help you out with this. What you can try is check and re-check all the connections. The only thing what I think is that it is somehow related to the groundshielding. But you tried evrything already. As you can see I am waiting for answers too for more than a week now. I think they must be bussy or on a short break...... 
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Why are you using those caps in the output wires? You can zero out the DC potential between Bal Out+ and Bal Out- by adjusting VR1 & VR2.
Have you tried without those caps ?
Also, clear the wire routing, no wire should be crossing each other. Also applies to the ribbon cable.
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Hi Jordo,
many thanks for your thoughts! And you're right: checking everything another time is always the best to do, sometimes one can't see the obvious!
Hi avr300,
the caps are there to deal with the common mode DC coming from the legato when used balanced. My pre/amp combination would nicely amplify this and put it in the voice coils of the speaker. I used here 1uF MKP bypassed by a small 0,1uF cap.
You're absolutely right about the wiring. But the strange thing is that if I run it in SE the noise is gone. And if I move the wires and crank up the volume the noise and its level remains the same. (So it is likely not a problem here.)
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You could try disconnecting power to the Buffalo, only keep the Legato powered. From that experiment we can conclude whether the noise is comming from the DAC or not.
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That's an also easy but clever idea. I'll report back when it's done (will take a few days, because at the weekend I'm not here...).
Thank you very much!
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Hi all,
I rewired, had a software bug in my network player feeding the buffalo, but now it sings like it is meant to! No hum, the noise is gone, i think it is as perfect as a legato can go. Thank you for your kind help!
Kind regards,
Matthias
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Congrets Matthias!!  Enjoy! Jordo
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