Buffalo-IIIse silent with new spdif source

[spresto9]

Hi all,
Please help, having just built this ADC (96/24) AD24QS - Audio Analog to Digital Converter 24 Bit / 192 kHz to run my Retro into my Buffalo-IIIsePro-28, I have no sound, the Spdif input on my B-111 works great with my CD, both the ADC and CD work fine into another DAC (Tascam)With the ADC connected to the Spdif input I get only silence but the lock led lights, the spdif output from the ADC is standard 0.5 VPP @ 75 Ω terminated.
Please help I'm a bit stumped,
Many thanks
Spresto9

 

[spresto9]

A bit more info, my dac has two inputs, i2s via a Teleporter and s/pdif connected directly to the s/pdif and gnd input and selected by a switch on ip/s.
My CD (consumer level s/pdif) works great via a bnc cable into the Buff dac, if I then connect my newly built ADC (consumer level s/pdif) to my Buff dac with the same cable I get no sound but lock led lights, however if I connect either the ADC or the CD using the same cable to my Tascam dac I get music in both cases.
I have tried reversing the polarity of the s/pdif (didn't know it mattered, the output on the ADC is transformer isolated) - no change, currently there switching between ADC and CD in the ADC box using OTTO 11 and this works fine, in the dac no switching (other than selecting S/pdif or i2s in the dac)

This is what the output of the ADC looks like direct into the scope and on the input fof dac (not sure it looks right or not)
Direct


Dac input








Cheers Steve

 

[spresto9]

Bit of an update,
I have discovered that if I route the digital signal from the ADC via the Tascam dacs pass through to my B111se it plays and I get sound,not sure what this means.I have also tried all of the ADC sample rate settings, results are unchanged

Cheers Steve

 

[spresto9]

Bump

 

[spresto9]

BUMP

Still havent resolved this please help if you have any ideas.
10000 views and no opinions!
Cheers
Steve

 

[francolargo]

It appears the AD24QS is outside of the experience of your readers. I have no educated guesses concerning your problem, but it is "curious".

If I were you, I would carefully compare the ADC spdif output signal to the TASCAM signal. What are the differences?

The following is purely speculative... The ADC signal at the B3 DAC (if I understand its source correctly) shows some rather round shoulders that perhaps the TASCAM can read and improve upon. Perhaps the ES DAC can't parse the ADC's PCM, though clearly it can manage the TASCAM PCM signal, this is not defective. Is there an option to increase the ADC spdif signal to TTL, or buffer it with an opamp (Sparkfun or similar mini-board?), or both? Perhaps that would alter the situation. The ESPro GPIO 1-4 spdif inputs *are 5v tolerant*.

BTW, I have a very similar model of old, slow, analog 'scope!

Sticky problem - good luck.

 

[BrianDonegan]

Try routing the signal to the D1 pin of the Buffalo, which will bypass the SPDIF level converter. Can you show the measurement of the p-pV of the SPDIF signal? My only guess is that it is not the standard 0.5Vp-p.

 

[spresto9]

Hi Brian,
thanks for responding, I have tried input direct to D1 and GND, no sound and this time no lock.
Not sure if i can trust my scope its very old "iffy" and so is my knowledge, here are two snaps of the output, one of the ADC and one of the CD player for comparison the level of both seems to be .9v but in the photos further up they measure .5v with the same settings on the scope (.5v/dev)

Thanks Steve

ADC


CD

 

[francolargo]

The little dark loop at the very bottom left of your scope is a calibration output of 0.5v. Touch the probe to it (if it is working...) and you'll get a .5v deflection.

 

[spresto9]

OK
just had a chance to check the scope, both ADC and CD signals are at about .9v CD works fine but ADC causes the lock ied to light but no sound (spdif input) both signals are routed through OTTO.

Many thanks

Steve

 

[francolargo]

I think you've shown that the Twisted Pear components are working, but that only the AD24QS is incompatible with them. So my final thought is that you should try every possible ADC output option - sample rate, level, etc. - and then direct further queries to the ADC's designer.

 

[BrianDonegan]

I agree. It seems like the DPLL is able to decipher the clock, but data isn't decoding correctly. I have only see this when the source was encoding multiple channels rather than stereo.

 

[spresto9]

Thank you Brian and Francolargo I will try to contact the designer and report further
Cheers
Steve