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Hi, I am using two Legato 3.1 with buffers in dual mono configuration. When I connect directly to my pre amplifier (yba passion 1000),there is big distortion and i hear tik-tik from the legatos (i think the tik-tik come from the relays). I put coupling caps and it is ok now. When i connect to power amp (same brand) with the coupling caps, there is a loud BRRRRRR from the speakers The same hapens when i use Ventus after legato for bal/se. Any help would be appreciated. Theodosis 
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I take it you connect them using the XLR inputs? A few pictures might help.
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Thanks LeonvB,
Yes, legato 3 dual mono conected using xlr.
I am using stock parts exept I have replaced the opamp with 2 opa 627.
Legato is OK. I think there is an incompatibility with YBA gear.
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How have you verified the Legato is ok? Did you test it with another amp?
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Yes, I conected to the yba preamplifier with the coupling caps and the sound is exalent
Without coupling caps there are tik tik from the relays and distortion
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It is likely the YBA gear does not like DC offset at all. You could try the IVY3 to see if that is a better match.
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My DC offset voltage is absolute 0.00
I will try transformers
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Some power amplifiers have some input DC offset and simply can't be DC coupled to anything. Still that is very rare. You might try the stock op amps just in case the problem is parasitic issues because of your adapter. I would never suggest using a single to dual adapter there. Edited by user Wednesday, September 28, 2011 2:29:43 PM(UTC)
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Thanks Russ,
I am afraid you have right about input DC offset of the amplifier or preamplifier.
The question is I have capacitors in line. Only pin 1 of xlr is direct connected.
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Russ, I had an amp with problems today too: an Lyngdorf SDAI 2175. Which coupling caps would you recommend, and at what pins?
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This is my dac [img]  [/img] After long investigation,it seems that the hum starts when connect gnd pin (gnd+d1) from one dac to other. There is hum even if the dac is switched off. How can I isolate this gnd line?
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I replaced the opa627 with the stock opamps. Same problem
The hum comes only from the left chanel only when the GNDs of the DACs are connected.
An isolation tranformer would help?
or a star ground ?
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When you connect to the amp using balanced outputs, did you try not connecting the GND (just +out and -out)?
As an experiment, try powering both DACs from the same PSU.
For connecting grounds, join output GND of both LCDPS with a wire, then wire to the DACs as you have them. There should ideally be no other GND connection between them, including the S/PDIF input GND (connect it to just one of the DACs).
Question... what's going on with the LCDPS wiring? Are you using one side as a pre-regulator to drive the other side or something? And why?
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Thanks Brian,
I connected to the amp using balanced outputs without gnd but did not work
I will do the connection with GNDs and ill revert.
Yes I am using one side as a pre-regulator (2 blades shave better than one)
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Hi Brian, I did the connection with the grounds as described but the hum is still there. Any other ideas? 
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It has to be a ground loop or EMI (though this is somewhat less likely). so the place to start will be to eliminate things until it goes away, then figure out why what was there is causing the loop. Or you could do the opposite, starting with one channel only, then adding things. Edited by user Tuesday, October 4, 2011 7:39:44 PM(UTC)
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Finally the problem with the hum solved when I connected pin 1 of XLR to the chassis.
Thanks Russ and Brian and congatulation for the Legato 3.
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