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AlexanderT  
#1 Posted : Friday, June 19, 2015 7:39:48 PM(UTC)
AlexanderT

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Hello,

I have a problem with Legato - i was listening normally when a terrible noise started to rise in one channel. Now any time i turn it on - i can hear perfectly normal music until i try to increase volume (integrated digital) beyond certain setting (slightly more higher than lowest setting) and a noise starts until i go back to lower volume level and it sounds ok again. It sound like a white noise.
Right now i'm testing with headphones connected directly to Legato HP_out, but same problem with other outputs.

There's also slight rise/fluctuations in DC across balanced outputs when noise starts but not too much, up to 10mA

Previously i tested higher voltages and ran Legato with assymetric +14V \ -14.5V as some suggested on forums to see and measure how it will affect the performance.

Any suggestion where do i start looking for a problem?

Edited by user Friday, June 19, 2015 7:48:44 PM(UTC)  | Reason: Not specified

avr300  
#2 Posted : Friday, June 19, 2015 8:36:37 PM(UTC)
avr300

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It could be everything.

(You might check the signal coming out the DAC. Perhaps its not the Legato)

Start by checking the connection to the DAC. Take off the DAC, put it on again.

It might be a faulty pot, give them a little stir.

Look for dry solder joints.

Also take a look here http://www.twistedpearaudio.com/forum/yaf_postst2000_Crackling-sound.aspx

AlexanderT  
#3 Posted : Saturday, June 20, 2015 10:20:39 AM(UTC)
AlexanderT

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Yes, it seems problem was digital side related, although i have no idea how this could happen, but i was surprised when i switched FIR filter to slow mode and it fixed the noise on any volume level, yet Fast mode had noise above certain volume level. Quick measurement showed weird noise and distortions around and above 20khz, but after i restarted the dac, rechecked everything and put it back together - the problem was gone :(
I'll try to replicate it again to find what caused it

Thanks AVR!
AlexanderT  
#4 Posted : Wednesday, June 24, 2015 8:30:47 PM(UTC)
AlexanderT

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The noise (in both channels) appear when i have DSD to PCM plugin in Foobar set to output 352khz pcm. With fast FIR filter mode noise just starts above some level of volume. Lowering PCM output frequency or using slow FIR fixes this. Maybe i need shorter/better I2S connection or such sampling is too much for buffalo itself?


I also found that i get randomly changing DC between both balanced and SE outputs when running Buffalo 3SE at full volume with signal. It jumps between +10 to -10 depending on signal playing. The more bass in the music the larger DC numbers, and when playing Noise i can see as much as +\- 100mV! Is this normal? Or is it my voltmeter...

P.S. i did some reading and realized it's normal. So i guess all my problems solved for now

Edited by user Saturday, June 27, 2015 7:13:53 PM(UTC)  | Reason: update

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