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At last... (Audiolab) - part I

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Thanks for that John, a really great insight into many things, whilst I don't really understand the techy bits I definitely feel more informed. Come on then, when do the shops get some stock?!!!
 
Hi John W, I'm one of the DaCapo owners who've been following deveopment your new product over on the diy forum for about 5 years years now, and the CDQ is looking like a great bit of kit :)

Just one question though... Without changing my amp (which I'm not ruling out at a future time), how do I connect it to my existing Audiolab 8000AP with its line-level RCA inputs ? I don't see any analogue RCA outs on the images I've seen for the CDQ.... or am I missing something ?? I'm not much of a techie !

Thanks in advance

<edit>
Ah..... I think I see them now. Is that them next to the balanced outputs ? It's not a particularly high-res image I'm looking out, and they lstill ook quite big - almost like BNC connectors ... ?
 
spacey said:
Dan Lavry white papers: www.lavryengineering.com/documents/Sampling_Theory.pdf

Conclusion:

There is an inescapable tradeoff between faster sampling on one hand and a loss of accuracy,
increased data size and much additional processing requirement on the other hand.
AD converter designers can not generate 20 bits at MHz speeds, yet they often utilize a circuit
yielding a few bits at MHz speeds as a step towards making many bits at lower speeds.
The compromise between speed and accuracy is a permanent engineering and scientific
reality.
Sampling audio signals at 192KHz is about 3 times faster than the optimal rate.
It compromises the accuracy which ends up as audio distortions.
While there is no up side to operation at excessive speeds, there are further disadvantages:
1. The increased speed causes larger amount of data (impacting data storage and data
transmission speed requirements).
2. Operating at 192KHz causes a very significant increase in the required processing
power, resulting in very costly gear and/or further compromise in audio quality.
The optimal sample rate should be largely based on the required signal bandwidth. Audio
industry salesman have been promoting faster than optimal rates. The promotion of such ideas
is based on the fallacy that faster rates yield more accuracy and/or more detail. Weather
motivated by profit or ignorance, the promoters, leading the industry in the wrong direction, are
stating the opposite of what is true.
Click to expand...

On the other thread
 
I've just pre-ordered the 8200CDQ from my dealer :)

Now then, does anyone know of a PC sound card with a Toslink clock input that would work with it? Or would I be better off using the Async USB ?
 
TimR,

It would be best to connect the CDQ directly to your Front L/R Channel Amplifier / Speakers, and the “Front L/R Audio Outputs” from your AP routed to say the “Video” Analogue input on the CDQ set to “Home Theater” Mode (many thanks to Bolle for remaining me to add the functionality). Connecting your system in this manor allows the optimal Stereo Hi-Fi performance – without degrading your AV experience.

Spacey,

I’ve had a run-in with Dan Lavry in the past – I certainly don’t agree with everything he says (or does).

1. Data storage and increasing processing speed comes for free these days – when we are trying and spend so much to squeeze the very last ounce of performance from Hi-Fi, doubling or tripling the resolution of the source material for very little money seems like a bloody great deal!!!

2. What a load of crap – hey therefore we should never try to progress – because everyone’s happy with the sound of Digital – you know nobody listens to turntable these days… Not now that Digital is so much better!!! – Yeh right!!!

Why would you throw away the chance to increase the resolution of your Data source – remember poor signal in / poorer signal out…

I cannot be bothered to see if Lavry units support 192KHz input sources, otherwise I cannot understand why he’s so against it – we support 192KHz – not that I’ve EVER had a chance to listen to a true 192KHz source (we test functionality by upsampling standard 44.1KHz) – it basically cost nothing these days, so might as well offer the option. I’m not saying that anyone needs to use 192 KHz – but we can, so we do, good luck finding a source of 192KHz Music – the one thing you can be assured of, it certainly will not be WORST then 44.1KHz, so why not (if you can)?

Muzzer,

We use the ESI Julia sound card in our LAB – its one of our 192KHz test source’s – a very good card.

For the record, its 44.1KHz, 88.2KHz & 176.4KHz outputs are quite low Jitter, however Jitter in 48KHz, 96KHz & 192KHz is worst – most likely due to the way Julia generates the internal clocks (they take on a bi-modal distribution).

Due to our use of Async. USB – USB offers the BEST method of connecting to a PC (with lowest Jitter) – I’m sure that for 99% of users the limit of 24/96 over USB will not be an issue.

If you really require higher sample rates, then ESI Julia via Coax is your next best route.

Good luck in sourcing CDQ’s over the next few months, none have been shipped too date (due to ship in the next couple of weeks)…
 
JohnW said:
It would be best to connect the CDQ directly to your Front L/R Channel Amplifier / Speakers, and the “Front L/R Audio Outputs” from your AP routed to say the “Video” Analogue input on the CDQ set to “Home Theater” Mode
Click to expand...
And just when I'd been preparing myself for a bit of daily cable swapping... you seem to have thought of everything. Very impressed :D

I currently use the 5.1 bypass inputs on the 8000AP for both my turntable and my DaCapo - swapping cables each time. In the configuration you mention, will I be able to also connect the turntable to the CDQ instead? If so, then I'm guessing that your pre-amp will outperform the analogue section in the 8000AP ?
 
It all sound very, very good! Probably going to get a 8200DQ, as I have no real need for a disc spinner, and I prefer a volume knob and the 12V trigger (if that can be added) of the DQ.

Can't wait for them to hit the stores! (or a few pics ;))
 
Hi John, can you say a little about the TDA type amps (power dacs) youve made, i find the concept interesting, after owning Lyngdorfs/Tact TDA amps, which while not perfect, had some real qualities.

I notice a few other companies have started to make this type of Power Dac (Hiface, Wadia etc), although non with the power of the Tact/Lyngdorf amps.
Can you also say why you've used the ESS chip and not the multiple dacs you were going to use in the original design, thanks. :)

Oh and some sneeky pics of the DQ would be good too :cool:
 
muz640,

To me, the greatest advantage of "Digital" power amplifiers is the simpler signal path - the best sounding system I've ever worked on where:-

1. A direct drive Valve OTL ESL speaker system (No step-up transformer) based upon a modified Acustat Circuit... 6HB5's I remember.... just incredible

2. Class D based "Digital" amplifier, with digital modulator - wish it could have driven my ESL's without the Step-up transformer.

I'm being push by Dominik (who would write the FPGA software) to release our Digital Amplifier, but just overloaded with Audiolab & Peachtree design work...

The ESS is very much based upon the same principle as our "array DAC", but where we might have only been able to use say 64 DAC’s elements per channel (due to size and cost), ESS being based upon integrated silicon can squeeze 256 DAC elements per channel... Game over for our discrete solution...

Boffotheloon (?)

There’s been a slight delay on the CDQ production (not unexpectedly), while we work on resolving 8200CD production related issues as they crop up. We are just building the first 200 Pcs of CDQ, so they well reach the shops within the next couple of months. Unfortunately, the lead times of components is going in the wrong direction – with items like LCD’s arriving in late October… ATM we have 500Pcs on hand, but these well not last long…

If anyone’s interested, this month’s issue of What Hi-FI has a first test on the 8200CD…
 
To be honest John i'd be more interested in you sneaking a CDQ out the back door and sending it over here so we can all pass it around and review it ourselves. ;-) I guarantee there's more people read, PFM, Wigwam and computer Audiophile than the collected print output of the UK hifi press these days.

Given that Malcolm Steward can claim that a Sata cable, from hard-disc to motherboard, can improve the quality of digital playback we aren't exactly over flowing with respect for journos round these parts.
 
That's a good point, don't forget there are forum 'personalities' that we get a good handle on over the years, so it could be quite enlightening to hear their POV.

I am very interested in your designs John, but I don't need the pre-amp function. I understand there would be no loss going for the CD rather than the CDQ - that is if I can't restrain myself to wait for the MDAC (or whatever it'll be released as). Is this right?
 
sq225917,

I can totally understand where you coming from, however it’s not fair to put all reviewers under the same hat. I have great deal of respect for the guys at HiFi world (David Price etc), WhatHiFi was an unknown quantity to me, but I recently met the editor and he turns out to be a really sound guy - this should not have come as too much as a surprise to find out that he worked at HiFi World... There’s also Alan Sircom and others - people who are not afraid to stand up against the "Establishment" and the Gentleman’s club...
 
Thanks for the reply John. Excellent that your so busy with work. Look forward to see what your going to come up with for the rest of the Audiolab range.
I think if you did release your own designs they'd be very well supported indeed.
Look forward to the review of the 8200 CD player.

So the Dac... what with them not being a "Dac company:D" realistically is that looking like 2011 now?
 
Hi would the CDQ be compatible with a Bryston power amp? I was considering
the Bryston dac/pre/power set up with my old cd player, but the CDQ looks interesting in a single box.I could get by until the CDQ is available but I need to buy a power amp now due to my old one dying.

W
 
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