Audio-GD Reference 7 - the new flagship DAC
May 27, 2011 at 7:24 AM Post #2,326 of 2,738

axw

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Quote:
Also wanted to mention that it seems like the Ref 7.1 is much more immune to transport variances than the Ref 7 was.  Before there were very clear differences and now not as much.

 
Sorry, but how can a change to analog output stage affect transport susceptibility?  If anything, wouldn't it be the other way around: by improving the analog section (leaving the digital part unchanged) transport changes are MORE apparent?

Please, find somebody with a Ref 7 around and compare both directly..
 
May 27, 2011 at 4:13 PM Post #2,327 of 2,738

IPodPJ

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Quote:
Sorry, but how can a change to analog output stage affect transport susceptibility?  If anything, wouldn't it be the other way around: by improving the analog section (leaving the digital part unchanged) transport changes are MORE apparent?

Please, find somebody with a Ref 7 around and compare both directly..


I guess you didn't read what I wrote before, so I'll say it again.  There were obviously other changes made to the DAC as well.  There are no more relay clicks when you switch digital inputs, so whatever method he is using now is different.  There might be other changes he has made that he hasn't specified.
 
Macrog has done a direct comparison.  Ask him for his opinions.  He can't post them publicly because he sells their gear.
 
 
May 29, 2011 at 1:34 PM Post #2,328 of 2,738

jax

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Quote:
I guess you didn't read what I wrote before, so I'll say it again.  There were obviously other changes made to the DAC as well.  There are no more relay clicks when you switch digital inputs, so whatever method he is using now is different.  There might be other changes he has made that he hasn't specified.
 

 
FWIW my late (one of the last produced) version of the Ref. 8 (basically the "musical" version of the Ref. 7 according to Kingwa) has never had any relay clicks when swapping inputs - it is silent as a grave in those transitions.  The only audible transition I've heard from it is a very light thump when powering down the unit on the rare occasion I forget to turn down the volume. 
 
 
 
May 29, 2011 at 5:52 PM Post #2,329 of 2,738

sokolov91

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Quote:
 
Sorry, but how can a change to analog output stage affect transport susceptibility?  If anything, wouldn't it be the other way around: by improving the analog section (leaving the digital part unchanged) transport changes are MORE apparent?

Please, find somebody with a Ref 7 around and compare both directly..

if the chip re-clocks everything to 50ps from my understanding it pretty much makes anything beyond that meaningless.
 
Doesn't matter if your source is 0 to over 9000 ps when the DAC will rearrange it automatically to 50, right?
 
It is like the PEA in chocolate that people advertize as an aphrodisiac... you can consume as much of it as you want, but unless you have an MAOI it is worthless because your first-pass metabolism won't let it get past the blood-brain barrier. Just like with the Ref - 7... doesn't matter what the jitter of your source is before the ref - 7 because it is 50ps no matter what at the end of the line.
 
However, I suppose the logic changes if you turn the DSP off, but then why drop 1700$ on a DAC in the first place :p
 
 
May 29, 2011 at 6:11 PM Post #2,330 of 2,738

IPodPJ

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Quote:
 
 
FWIW my late (one of the last produced) version of the Ref. 8 (basically the "musical" version of the Ref. 7 according to Kingwa) has never had any relay clicks when swapping inputs - it is silent as a grave in those transitions.  The only audible transition I've heard from it is a very light thump when powering down the unit on the rare occasion I forget to turn down the volume.


Well maybe that's how the Ref8 was, but I can tell you I had two Ref1s and a Ref7 and they all had relay clicks between switching inputs.  Surely anyone here that owns these can confirm this.
 
 
May 29, 2011 at 6:16 PM Post #2,331 of 2,738

IPodPJ

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Quote:
if the chip re-clocks everything to 50ps from my understanding it pretty much makes anything beyond that meaningless.
 
Doesn't matter if your source is 0 to over 9000 ps when the DAC will rearrange it automatically to 50, right?
 
It is like the PEA in chocolate that people advertize as an aphrodisiac... you can consume as much of it as you want, but unless you have an MAOI it is worthless because your first-pass metabolism won't let it get past the blood-brain barrier. Just like with the Ref - 7... doesn't matter what the jitter of your source is before the ref - 7 because it is 50ps no matter what at the end of the line.
 
However, I suppose the logic changes if you turn the DSP off, but then why drop 1700$ on a DAC in the first place :p


I really wish people would stop using the word jitter like it's some blanket statement that covers everything.  It isn't.  There are many types of jitter, and there are other factors at works, such as the stability of the oscillator measured in ppm which is different than the jitter levels.  But if you want to know about all the different kinds of jitter, why don't you read from Altera's site all about jitter, which is especially relevant with the DSP-1 module:
 
http://www.altera.com/support/devices/pll_clock/jitter/pll-jitter.html
 
 
May 29, 2011 at 6:21 PM Post #2,332 of 2,738

sokolov91

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I really wish people would stop using the word jitter like it's some blanket statement that covers everything.  It isn't.  There are many types of jitter, and there are other factors at works, such as the stability of the oscillator measured in ppm which is different than the jitter levels.  But if you want to know about all the different kinds of jitter, why don't you read from Altera's site all about jitter, which is especially relevant with the DSP-1 module:
 
http://www.altera.com/support/devices/pll_clock/jitter/pll-jitter.html
 

Ty for the link and yes it is quite relevant ahaha.
 
 
 
May 29, 2011 at 6:29 PM Post #2,333 of 2,738

sokolov91

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How can one induce jitter then?
 
Like can I take my transport cable and shake it and hear a difference, other than mechanical noise? (serious question) Or like strap a vibrating razor or toothbrush to it?
 
I have a few transports, nothing high end by any means, but in addition to swapping them out is there a computer program / dsp you can use to emulate it's presence?
My reasoning its it is best to know what you are looking for, before starting a search.
 
 
Can you turn the de-jittering off in the Ref-7 but keep everything else on?
 
 
 
May 29, 2011 at 8:15 PM Post #2,334 of 2,738

Pricklely Peete

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Quote:
How can one induce jitter then?
 
Like can I take my transport cable and shake it and hear a difference, other than mechanical noise? (serious question) Or like strap a vibrating razor or toothbrush to it?
 
I have a few transports, nothing high end by any means, but in addition to swapping them out is there a computer program / dsp you can use to emulate it's presence?
My reasoning its it is best to know what you are looking for, before starting a search.
 
 
Can you turn the de-jittering off in the Ref-7 but keep everything else on?
 
 


Any number of ways....poor timing, phase error, laser drive tracking error (as in excessive error correction) caused by excessive vibration (poor clamping) or poor servo / DAC drive integration, disc defects, improper termination at transport and dac, PSU noise is a killer for digital transports and DACs....that's all I can come up with for now...that Alterra link is a good one.
 
Anyway...getting a little OT here......I have the very early rev RE1 (one of the first to be shipped from A-gd overseas with the then brand new DSP-1 module) with just 2 inputs (BNC and RCA) which has no relay but you do hear a click when the transport sends a signal to the DAC...that click is the "lock" on the signal. There is no other switching circuitry in my RE1. That's the way I like it however...for one use and one use only.
 
Peete.
 
 
May 30, 2011 at 2:06 AM Post #2,335 of 2,738

IPodPJ

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Quote:
Any number of ways....poor timing, phase error, laser drive tracking error (as in excessive error correction) caused by excessive vibration (poor clamping) or poor servo / DAC drive integration, disc defects, improper termination at transport and dac, PSU noise is a killer for digital transports and DACs....that's all I can come up with for now...that Alterra link is a good one.
 
Anyway...getting a little OT here......I have the very early rev RE1 (one of the first to be shipped from A-gd overseas with the then brand new DSP-1 module) with just 2 inputs (BNC and RCA) which has no relay but you do hear a click when the transport sends a signal to the DAC...that click is the "lock" on the signal. There is no other switching circuitry in my RE1. That's the way I like it however...for one use and one use only.
 
Peete.
 


Well I had a number of issues with my DACs so it wouldn't surprise me.  In either case, the RE7.1 does not have any clicking on signal lock.  Only sometimes you hear a click in the audio between input 2 and 3, but no mechanical click in the unit.
 
 
May 30, 2011 at 3:52 AM Post #2,338 of 2,738

macrog

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The Ref7.1 has a faint click between inputs not mechanical (I guessed it was just achieving lock).
 

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