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At last... (Audiolab) - part VII

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stellablues,

The CROSS (Current Regulated Output Stage Solution) had been developed back in the mid 90's - but got put to one side while I concentrated upon research into Class D.

Dominik and myself resurrected CROSS for our own DAC but once again this was put onto a back burner to concentrate first on the Peachtree products, then Audiolab.

"CROSS" itself is an output stage design, however to achieve best results we also designed a nice fully discrete JFET front-end (replacing the front end section of the AD744 used in the CD / CDQ).

Following the 8200CD winning the WHF awards in 2010 we reached an agreement with Audiolab to licence some of our more "juicy" technologies, so very late in the design stage, around June this year the MDAC was redesigned from a "standard" discrete Class A stage to our "CROSS" stage. The CROSS stage and the Digital Domain Decorrelation Engine (D3E) are the main reason's for MDAC's improved sound quality over the CD / CDQ.

John
 
Thanks for the summary. That is very helpful.

I take it is a discreet output stage biased to class A and with some additional benefits to impedance.

Searching using these keywords I was able to find this from an earlier post here on this site which also give some additional details:

“CROSS” is a stupid acronym I thought up to “Christen and Promote” a nice little circuit / output stage topology – its stands for “Current Regulated Output Stage Solution” which I developed back in 1996/7 primary for Bias stabilisation and gain linearization around the Cross-over region of Class A/B amplifiers (not much benefit in MDAC as we operate fully in Class A), but it also has a secondary effect of dramatically improving output stage impedance and linearity – which IS beneficial in our MDAC application (atleast according to simulation and measurement results).

Looking forward to some reviews.
 
seranil said:
I haven't seen many measurement so far or concrete evidences that the MDAC would sound any better than any other DAC in the same price range.
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See that's the problem (putting the sound quality aside for a moment) there aren't any dacs in this price range with the same functionality and features of the MDAC, if there were i'd have bought one long ago! :)
 
Just remember all the hype about the Young? Well, personally I didn't find it to be sounding any better than my TC Konnekt so excuse me is I am sightly doubtful of the many unsubstantiated claims made in this thread. I am very likely to give the MDAC a go but past experiences taught me to be very suspicious of any claims coming from the "Hi-Fi" world.
 
Seranil, where abouts are you?
Perhaps some kind soul can arrange to bring their M-Dac to yours for a head to head as it were, let you make your own assessment. You sound un-biased so probably make for a good test. :)
 
seranil said:
Just remember all the hype about the Young? Well, personally I didn't find it to be sounding any better than my TC Konnekt so excuse me is I am sightly doubtful of the many unsubstantiated claims made in this thread. I am very likely to give the MDAC a go but past experiences taught me to be very suspicious of any claims coming from the "Hi-Fi" world.
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They're not unsubstantiated though are they, lots of people have got the CD and the CDQ and think they're great.
If it sounds as good as the Dacmagic and replaces a separate headphone amp, preamp and drives long cables, I'll be happy.
 
Hi, Sam
I am in London. I would love to try the MDAC and proved wrong but I got burned many times in this endless games. It is just so hard not to get caught into the hype machine. ;)
 
I am also interested in the mdac

I have an oppo 95 connected via analogue out to a tag av32r processor
I realise the dac in the oppo is very good but I want to improve other sources spotify/Napster
Is there likely to be much improvement given the relative low quality of spotify/Napster
Can it be slotted into my setup for 5:1 even if I set the volume manually prior to the av bypass option
 
seranil said:
Hi, Sam
I am in London. I would love to try the MDAC and proved wrong but I got burned many times in this endless games. It is just so hard not to get caught into the hype machine. ;)
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Bound to be someone on PFM with one near, be good to hear (lol) your opinion of it.
I trust JohnW's designs, I like how my CDQ sounds and if its better then no bad thing.

Sam
 
Hi JohnW,

Can you explain (without giving away trade secrets) what D3E does in the digital domain?

Thanks!
 
Just remember all the hype about the Young? Well, personally I didn't find it to be sounding any better than my TC Konnekt so excuse me is I am sightly doubtful of the many unsubstantiated claims made in this thread. I am very likely to give the MDAC a go but past experiences taught me to be very suspicious of any claims coming from the "Hi-Fi" world.
Click to expand...

Once bitten, twice shy?

Nobody would expect you to buy it on the strength of the consensus or hype of others. Your own experience would need to concur and therefore be added to that body of consensus. If you heard it and it sounded better to your ears would you then accept that it was better or would remaining doubts linger and trouble you?

Would superior measurements taken by an independent body remove those final lingering doubts. Would you buy solely on the strength of such superior measurements without checking that they were of any significance in terms of your own sensory experience?
 
Steven Toy said:
Once bitten, twice shy?

Nobody would expect you to buy it on the strength of the consensus or hype of others. Your own experience would need to concur and therefore be added to that body of consensus. If you heard it and it sounded better to your ears would you then accept that it was better or would remaining doubts linger and trouble you?

Would superior measurements taken by an independent body remove those final lingering doubts. Would you buy solely on the strength of such superior measurements without checking that they were of any significance in terms of your own sensory experience?
Click to expand...

I would buy on the strength of superior measurements, but only if my knowledge and experience told me that these improvements were audible. Reducing distortion from say, 0.05% to 0.01% won't be audible. Reducing jitter from, say, 100nS to 1nS won't be audible. Extending the 3dB point from 20kHz to 30kHz won't be audible.

The problem with so much equipment these days is that what came before is already transparent, so what improvement can be made? I accept that from a designer's point of view there's the technical challenge of making it better, but if better doesn't translate to audibly better, then from a purchaser's point if view, it's rather pointless.

S.
 
Extending the 3dB point from 20kHz to 30kHz won't be audible.
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Are you 100% sure of this? Have you considered the possibility that how a circuit behaves outside the audible range may affect how it behaves within the audible range?
 
Space is the Place said:
See that's the problem (putting the sound quality aside for a moment) there aren't any dacs in this price range with the same functionality and features of the MDAC, if there were i'd have bought one long ago! :)
Click to expand...

When you say 'in this price range' are you referring to pre-order £500, normal retail £600 or plus upgraded PSU estimated at £300?

I believe the performance/VFM should be compared with other DACs available at around £900.
 
finesensations said:
When you say 'in this price range' are you referring to pre-order £500, normal retail £600 or plus upgraded PSU estimated at £300?

I believe the performance/VFM should be compared with other DACs available at around £900.
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Yes i think £600, although i can't really think of one at £900 that comes close either. :)
 
AndyU said:
How do you know what comes close to a DAC you haven't heard? (Or is that just a stupid question).
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No its not a stupid question at all! :) Like i put in my other post i'll be happy if it has the same performance as a Dacmagic, or approaches the performance of the EE Dac. I'll just make an assumption of SQ based on the the experience of others who have the CDQ etc.

But your right it might not be as good as one of the above in which case i could always sell it!
Ive had enough dacs to know the differences are small, i'm not expecting miracles, but ive been waiting for this since early 2008!
 
Space is the Place said:
Yes i think £600, although i can't really think of one at £900 that comes close either. :)
Click to expand...

For me, minimum connectivity functionality and features would come first, then SQ, then 'nice to have but not essential' connectivity functionality and features.

Are you really saying that you will NOT be buying the upgraded PSU?
 
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