Distortion with Buffalo dac please heelp.

kimschips · 23rd May 2010, 11:09 PM

Hey all.

I have a Buffalo Dac (ES9008) vers 1.

I have tried 2 different DVD player and a Squeezebox 3 with SPDIf output connected to my buffalo dac.

When I use the dvd players the sound is sometimes very distortet.
When I use my squeezebox 3 I set the digital output to 80% off maximum output, to prevent overload the input to the Buffalo dac and the sound is always clean.

Do any off you know how to lower the output from the dvd players or the input to my buffalo dac???

Anyone heard off this problem before?

Best regards

Kim

Javin5 · 24th May 2010, 12:23 PM

I have used the Buffalo SPDIF-input with signals from two different CD-players and a Sony BD/DVD-player and have never encountered any distortion. Make sure that you have a short SPDIF-connection with a reasonable quality 75 Ohm cable (no expensive boutique cable required). Also, you should check the voltage of the SPDIF signal on a scope to make sure that it is within specs (+- 0.5 V if I remember correctly) and has a clean, reasonable looking waveform. In case you refer to the numeriacally encoded level of the audio signal within the SPDIF frames, this would not be easy to change (and I doubt that it would be required).

Kurt

stormsonic · 24th May 2010, 01:22 PM

Quote:

Originally Posted by Javin5

I have used the Buffalo SPDIF-input with signals from two different CD-players and a Sony BD/DVD-player and have never encountered any distortion. Make sure that you have a short SPDIF-connection with a reasonable quality 75 Ohm cable (no expensive boutique cable required).

Correct word is long. If you can't control reflections, long is better

Quote:

Also, you should check the voltage of the SPDIF signal on a scope to make sure that it is within specs (+- 0.5 V if I remember correctly) and has a clean, reasonable looking waveform.

Unterminated should be 1V p-p and terminated 0.5V p-p. Without termination and scope probes attached there won't be clean waveform.

Check your Buffalo DAC, there should be problem. Or your digital cable.

Javin5 · 24th May 2010, 06:35 PM

Quote:

Originally Posted by stormsonic

Correct word is long. If you can't control reflections, long is better

... Unterminated should be 1V p-p and terminated 0.5V p-p ...

No. Short is correct. Cable length zero would actually be ideal.

And +-0.5 V is actually 1 Vpp.

Kurt

stormsonic · 24th May 2010, 07:50 PM

yes, cable lenght zero is ideal and termination is always ideal and there is no reflections and we live in perfect world of clean waveforms

Javin5 · 24th May 2010, 09:14 PM

Quote:

Originally Posted by stormsonic

yes, cable lenght zero is ideal and termination is always ideal and there is no reflections and we live in perfect world of clean waveforms

No need to be sarcastic; let's stay on facts here. What I'm saying is just plain, sound engineering. Not sure where the myth about the "longer is better" for SPDIF-cables originated, maybe from the cable manufacturers? You are of course free to believe whatever you prefer.

Kurt

Russ White · 03:56 AM

Hi Kim,

The as Brian has already told you, the problem is the DAC output level is much higher than your output stage (zap filter) is designed for. That is the reason why it sounds fine with the reduced output from the SB3(80% as you say). No mystery here.

Use an output stage that was designed for the DAC. IVY III would be a natural choice.

stormsonic · 25th May 2010, 08:36 AM

Quote:

Originally Posted by Javin5

No need to be sarcastic; let's stay on facts here. What I'm saying is just plain, sound engineering. Not sure where the myth about the "longer is better" for SPDIF-cables originated, maybe from the cable manufacturers? You are of course free to believe whatever you prefer.

Kurt

Yes, it is a little bit sarcastic. Please don't take it personally

Cable manufacturers are thinking about digital cable same way as for amplifier input interconnects. Wrong, it is not audio from 20Hz to 20kHz, it is RF.

I can measure my cables on TDR. If you can control reflections and attenuate them enough, fine, short cables will be OK. If you can't control reflections, you must delay them to arrive later. Then long cables are better. Or short cables are worse.

Everything is already written, people just need to read: LINK

Sorry for OT.

Javin5 · 25th May 2010, 04:47 PM

I think Russ has answered the problem of the OP.

Stormsonic, we obviously have different views regarding SPDIF cables, but that's ok. This is not a cable thread; there are enough of those, so we should not continue the discussion here. However, you are welcome to PM me.

Kurt

kimschips · 6th November 2011, 11:52 AM

Thanks for the inputs (except about cable lengt every one should now that if both ends off the cable is correctly terminated with 75R you should not get any reflections and so on.)

I love my Zapfilter2 and hope not to buy any new outputstage

Maybe I am not the only on with that problem?

Best reagards

23rd May 2010, 11:09 PM	#1
kimschips diyAudio Member Join Date: Dec 2004 Location: Denmark	Distortion with Buffalo dac please heelp. Hey all. I have a Buffalo Dac (ES9008) vers 1. I have tried 2 different DVD player and a Squeezebox 3 with SPDIf output connected to my buffalo dac. When I use the dvd players the sound is sometimes very distortet. When I use my squeezebox 3 I set the digital output to 80% off maximum output, to prevent overload the input to the Buffalo dac and the sound is always clean. Do any off you know how to lower the output from the dvd players or the input to my buffalo dac??? Anyone heard off this problem before? Best regards Kim

25th May 2010, 03:53 AM	#7
Russ White diyAudio Member Join Date: Jan 2005 Location: Nashville, TN, USA	Hi Kim, The as Brian has already told you, the problem is the DAC output level is much higher than your output stage (zap filter) is designed for. That is the reason why it sounds fine with the reduced output from the SB3(80% as you say). No mystery here. Use an output stage that was designed for the DAC. IVY III would be a natural choice. __________________ Less pulp more juice Twisted Pear Audio. Last edited by Russ White; 25th May 2010 at 03:56 AM.

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24th May 2010, 12:23 PM	#2
Javin5 diyAudio Member Join Date: Mar 2006 Location: Switzerland	I have used the Buffalo SPDIF-input with signals from two different CD-players and a Sony BD/DVD-player and have never encountered any distortion. Make sure that you have a short SPDIF-connection with a reasonable quality 75 Ohm cable (no expensive boutique cable required). Also, you should check the voltage of the SPDIF signal on a scope to make sure that it is within specs (+- 0.5 V if I remember correctly) and has a clean, reasonable looking waveform. In case you refer to the numeriacally encoded level of the audio signal within the SPDIF frames, this would not be easy to change (and I doubt that it would be required). Kurt

24th May 2010, 07:50 PM	#5
stormsonic diyAudio Member Join Date: Aug 2008	yes, cable lenght zero is ideal and termination is always ideal and there is no reflections and we live in perfect world of clean waveforms

25th May 2010, 04:47 PM	#9
Javin5 diyAudio Member Join Date: Mar 2006 Location: Switzerland	I think Russ has answered the problem of the OP. Stormsonic, we obviously have different views regarding SPDIF cables, but that's ok. This is not a cable thread; there are enough of those, so we should not continue the discussion here. However, you are welcome to PM me. Kurt

6th November 2011, 11:52 AM	#10
kimschips diyAudio Member Join Date: Dec 2004 Location: Denmark	Thanks for the inputs (except about cable lengt every one should now that if both ends off the cable is correctly terminated with 75R you should not get any reflections and so on.) I love my Zapfilter2 and hope not to buy any new outputstage Maybe I am not the only on with that problem? Best reagards