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Hi Guys,
I am finishing my Buffalo DAC(not 32) and its sounds great on my balanced K701. It's a standard configuration ( MUX + Buffalo with Volumite + IVY). Now, I've avoid connecting it to my main rig as I have some severe power off thump. Power on thump is not as bad. What will you suggest to somewhat minimize this problem?
Also, my DC offset on the balanced output is between 7-9mV and unbalanced is 2.5mV. Are those acceptable values? The balanced DC offset is not symmetrical, meaning on left channel I have 7mV between negative(inverted) and ground and 9mV between positive and ground balanced outputs. What can be the reason to have different offsets between + and - of the balanced output? I am sorry I have thrown so many question, but I relay looking forward to do some more serious listening coming weekend.
Thanks in advance,
Gjorgji
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What version is your IVY board? The on-board relay should be preventing thumps. Also, what voltage are you running the IVY at?
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If the relay is working correctly there will be no thump.
Thee offset you are measuring is in the normal range.
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Thanks a lot for the prompt reply. IVY board version is 2.01. I can heard the relay click on power off, not sure if its before or after the thump. I am getting the thump on the balanced outputs, did not try the unbalanced yet. Based on the schematic I think in my case the relay is not relevant.
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You especially should not have any thump at the balanced output. If you do I would suspect something is wrong parts wise or with the wiring.
Brian's question about the supply voltages still stands.
Also photos can help especially of the top and bottom of the IVY.
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Rank: Member
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Rank: Administration
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On initial inspection things look ok.
I can only guess at this point, and I don't like to do that :)
If I were you I would start by double checking wiring and make sure that your power amp itself so not have any offset at the inputs. this is not all that uncommon. If it does you may need to use input caps at the power amp. Some power amps just are not designed for DC coupling.
I have used several balanced power amps with the Buf32S and Buffalo. I have never had any thump at all. The SE side would have a thump if the relay were not there.
Cheers!
Russ
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Hi Russ,
This is happening with my AKG K710(balanced). I am not definitely attaching the DAC to my amp or preamp until I sort this out.
I'll double check the internal wiring and part again tonight.
Gjorgji
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That makes even less sense for the thump at headphones. Something is definitely not right.
I would check for leaky caps, and you may want to add a small resistance to each output just in case your cables are extremely capacitive.
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One more question: ths4131 are running very hot with headphones attached 60C. With no load about 45C. Is that OK?
Before getting all the caps out to check, any idea which cap can create that kind of DC offset on power off?
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