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Old 16th July 2009, 04:33 PM   #581
Crafty is offline Crafty  United Kingdom
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Default Optimising layout and wiring

Thought i would seek some advice from you knowledgable folks if you dont mind...
I have built a Buffalo 32 with dual analogue power supplies with seperate transformers, the sound is great and i am very happy with it but i wanted to be sure i had done everything possible to extract the best performance.

My questions are:

1) what is the optimal grounding arrangement - i have grounded the case through the transformer mounting bolt nearest the IEC power inlet. The dac board and PSU's are not grounded to the case and the xlr outputs and inputs are also isolated from the case. Is this optimal?

2) I have arranged the DAC in the case so the SPDIF coax and balanced output cables are short runs and so that the DAC board lives in the left corner of the 1 U case with all transformers and PSU on the right side - this means the power supply cables are not of equal length and are not as short as possible. The cables are twisted though. Is this acceptable or should i change it.

3) Is it ok to leave the DAC permenantly powered - it gets quite warm..

Pic attached of installation - rear panel now completed with all connector mounted.

Many thanks,

Luke
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Old 16th July 2009, 04:49 PM   #582
Beefy is offline Beefy  Australia
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Default Re: Optimising layout and wiring

Quote:
Originally posted by Crafty
i have grounded the case through the transformer mounting bolt nearest the IEC power inlet.

Bad idea. You might have created a short circuited turn through the centre of the transformer - essentially an additional secondary winding on the transformer that will generate an AC voltage through the bolt and in/around the case itself.
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Old 16th July 2009, 04:57 PM   #583
Muser is offline Muser  United States
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Default Buffalo Performance

My Buffalo configuration:
Signal source is a Sony DVD player.
The DVD goes into the MUX via coaxial cable. The MUX is connected to the Buffalo, using I2S (or whatever the digital connection the MUX isn't connected through S/PDIF).
I am currently using only one LCBPS, as I'm curing an assembly mix-up on a second LCBPS.

I have a few questions for anyone willing to reply and share feedback.

1) Would the sound/performance be any different if I connected the Mux through the S/PDIF to the Buffalo instead?

2) Do you notice a substantial difference in volume levels with different recordings?

By way of personal experience, I've had a couple of dozen CD players through my system for extended periods, from modest to excellent quality (Ensemble Dichrono/Dirondo ~ $15k, EAR Acute $5500) and never noticed such a difference in volume levels. If the range of a volume pot is represented by a 12 hour clock, to achieve similar perceived volume levels the difference might be as much as 2 hours.

I'm wondering if the difference is the use of the I2S (non-S/PDIF?) connection?

FWIW, this is not a complaint, the Buffalo sounded very good 30 seconds into the first recording, I've just never noticed such a difference in volume levels

In advance, thanks for your feedback.

Larry
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Old 17th July 2009, 03:54 AM   #584
fff0 is offline fff0  Singapore
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Hi Russ,

Can I use a Digital audio transformers like LUNDAHL LL1573 (1:1:1) and LL1589 (1:1:1:1) for 2~3 SPDIF inputs on a B32 without much penalty?

Actually, I dont like the idea of putting a Mux/ receiver in front of a B32 which I think may increases the jitter, am I right to think this way?
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Old 17th July 2009, 01:38 PM   #585
Javin5 is offline Javin5  Switzerland
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Quote:
Originally posted by fff0
Actually, I dont like the idea of putting a Mux/ receiver in front of a B32 which I think may increases the jitter, am I right to think this way?
If you feed the SPDIF directly into the Sabre chip, it uses its internal SPDIF/I2S converter. If you use the converter of the MUX-receiver, you input directly an I2S signal into the Sabre chip. Since the jitter rejection of the Sabre chip is excellent, I doubt that you will hear any difference between the two converters. Why don't you simply try it out and let us know?

Kurt
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Old 17th July 2009, 04:04 PM   #586
Beefy is offline Beefy  Australia
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Quote:
Originally posted by Javin5


If you feed the SPDIF directly into the Sabre chip, it uses its internal SPDIF/I2S converter. If you use the converter of the MUX-receiver, you input directly an I2S signal into the Sabre chip. Since the jitter rejection of the Sabre chip is excellent, I doubt that you will hear any difference between the two converters. Why don't you simply try it out and let us know?

Kurt

I've seen a LOT of anecdotal evidence that while the Sabre can pick up a direct SPDIF stream, it is FAR from ideal, and that the MUX offers a significant improvement to reliability in terms of achieving and maintaining lock.

But.... Better or worse jitter? Audible differences? Hard to say.
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Old 18th July 2009, 02:34 PM   #587
hybride is offline hybride  Netherlands
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Brian or Russ,

What is the minimum voltage for V-analog on the B32S to start function correctly?

Hans
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Old 18th July 2009, 02:40 PM   #588
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Quote:
Originally posted by hybride
Brian or Russ,

What is the minimum voltage for V-analog on the B32S to start function correctly?

Hans
The relays on the V1.1 boards (and thump buster for V1.0) are designed to work at 24V so at least +/-12V are required unless you use different relays. +/-15 is better.

If you have a V 1.0 board and don't user thump buster then you can safely go all the way down to about +/-6V Maybe even 5V I have not tried it. Lowering the rails there will harm PSRR and CMRR a bit, but not too bad.

Cheers!
Russ
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Old 20th July 2009, 02:16 PM   #589
69mach1 is offline 69mach1  Netherlands
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Hi

Finished my b32s, very easy to assemble.
I cut the traces near the outputs.
I am using the balanced outputs into my preamp.

First time power on, no lock. aha, swiched spdif on and there is lock.
music appears, always good, but left channel is much softer then the right channel. Ajusted the balance and it does sound very good straigt out of the box.

took it on the bench again and measured the output resistance, all 22 ohms, so the traces have been cut properly!!.

Measured the outputs while powered and there is a 0,5 v dc on the left channel + to agnd and - to agnd while there is none on the right channel.

Not going to connect it again untill this is fixed.

Since i am a noob in these matteres i don't know what is going on, so a little help here would be appriciated.

Thanks in advance
John
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Old 23rd July 2009, 07:56 AM   #590
69mach1 is offline 69mach1  Netherlands
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Ok so there was just 1 resistor missing, fixed it and it is playing nicely. Thanks Russ for the help.

Can't comment to much on the sound yet, it will have break in first.

John
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