CHORD ELECTRONICS DAVE

tkteo said:

   
I wasn't aware that Mr Watts' DAC designs are Delta-Sigma. Isn't the DSP section of the DAVE, Hugo, etc 48-bit?

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I think it makes no sense to categorize DACs as Delta-Sigma, R2R, etc in a competition where there is only one winner because many people already have their biases about these various DAC topologies that could possibly influence their decision.  Also, most of us want to buy the best DAC (period) and not just the best DS or R2R DAC so this type of categorization seems misguided here and as you've noted, the DAVE is not a DS DAC but it isn't an R2R DAC either.
 
It is also getting harder and harder to accurately categorize a DAC these days since there are now so many classifications that DACs can fall into and some DACs fall into multiple categories:  DS vs R2R vs pulse array vs switched capacitor; single-bit vs multi-bit; single-ended vs differential; oversampling vs NOS; discrete vs silicon, etc.  It used to be that single-bit DACs were always chip-based and multibit DACs meant R2R but then the Schiit Yggy comes out and it is a multi-bit DAC that uses silicon chips instead of a resistor ladder.  
 
The DAVE is not a silicon-based DAC (ie Delta-Sigma) even though it oversamples and while it is a discrete DAC and uses resistors, it is not an R2R DAC either.  Based on Rob's postings, the most specific categorization that I can provide the DAVE is that it is a single-ended FPGA 20-element Pulse Array DAC and it is the only DAC of its kind.

Romaz I note you have discovered the HFC cables and mentioned them a bit here. Have you tried their RCA digital cable with the DAVE? RCA to BNC adaptor would be required though.
 
Their cables have the most profound effect closest to source, i.e digital, then IC, then speaker cables. Well that's what I have found anyway. The High Fidelity Cables line is groundbreaking, far better than any others I have tried.

agisthos said:

  Romaz I note you have discovered the HFC cables and mentioned them a bit here. Have you tried their RCA digital cable with the DAVE? RCA to BNC adaptor would be required though.
 
Their cables have the most profound effect closest to source, i.e digital, then IC, then speaker cables. Well that's what I have found anyway. The High Fidelity Cables line is groundbreaking, far better than any others I have tried.

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It's nice to know someone else who has heard these cables and find them as groundbreaking as I do.  I have not heard High Fidelity's RCA digital cable but if I get the chance, I'd love to hear them.  I just got a set of their speaker cables and once again, wow!  

romaz said:

tkteo said:

The DAVE is not a silicon-based DAC (ie Delta-Sigma) even though it oversamples and while it is a discrete DAC and uses resistors, it is not an R2R DAC either.  Based on Rob's postings, the most specific categorization that I can provide the DAVE is that it is a single-ended FPGA 20-element Pulse Array DAC and it is the only DAC of its kind.

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The elements each fire for a fixed duration (common to all of them) and for a distinct part of the output cycle (so that no two elements fire together), so that they "join" up into what's seen by the analogue integrator as a single, long, pulse. The output cycle has fixed duration, so the pulse either fills that cycle fully or partially or there is no pulse.

This way you get a pulse of energy and a period of no energy during every cycle. The ratio between the two makes the analogue delta that produces the music. There is a fixed set of these ratios, along with two special cases: where there is no pulse and where the pulse fills the entire cycle. This is pulse density modulation.

Native replay of SACD and other DSD variants is the same process, though not at the frequency (104MHz) and power level (several watts) seen in DAVE.

DAVE's PDM DAC is preceded by up-sampling and noise-shaping implemented by the FPGA.

jawed said:

The elements each fire for a fixed duration (common to all of them) and for a distinct part of the output cycle (so that no two elements fire together), so that they "join" up into what's seen by the analogue integrator as a single, long, pulse. The output cycle has fixed duration, so the pulse either fills that cycle fully or partially or there is no pulse.

This way you get a pulse of energy and a period of no energy during every cycle. The ratio between the two makes the analogue delta that produces the music. There is a fixed set of these ratios, along with two special cases: where there is no pulse and where the pulse fills the entire cycle. This is pulse density modulation.

Native replay of SACD and other DSD variants is the same process, though not at the frequency (104MHz) and power level (several watts) seen in DAVE.

DAVE's PDM DAC is preceded by up-sampling and noise-shaping implemented by the FPGA.

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Thanks, Jawed, for explaining!
 
I have always asked myself what exactly this «Pulse Array» could be. Now it turns out to be based on Pulse Width Modulation (PWM), which I happen to be somewhat familiar with.
 
From above Wikipedia link:
 

 
 
 
 
 
 
 
 
 
 
 
 
«A simple method to generate the PWM pulse train corresponding to a given signal is the intersective PWM: the signal (here the red sine wave) is compared with a sawtooth waveform (blue). When the latter is less than the former, the PWM signal (magenta) is in high state (1). Otherwise it is in the low state (0).»
 
The German Wikipedia version adds: «For sufficiently inertial consumer loads the voltage curve functions as a sine curve.» Which means you just need a low-pass filter for D/A conversion (as in class D amps).
 

rob watts said:

   I had planned to listen to different mains cables, but have decided to make some up myself, as the available cables I am not 100% happy with from a RF POV.

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Rob, are you going to share how you will create the 100% happy cable for Dave? I guess everyone will be very much interested...

A general question for Dave owners:

Does owning Dave 'spoil' listening experiences for times when you don't have access to Dave?

I am curious.

I've become "dependent" on Mojo. I don't have interest in listening without it.


I'm also interested in what headphones Dave users like. Presupposing that they aren't limited financially, what headphones and or in ear monitors do Dave owners most enjoy?

That's two questions...


Thank you. This is an interesting thread.

peter hyatt said:

A general question for Dave owners:

Does owning Dave 'spoil' listening experiences for times when you don't have access to Dave?

I am curious.

I've become "dependent" on Mojo. I don't have interest in listening without it.


I'm also interested in what headphones Dave users like. Presupposing that they aren't limited financially, what headphones and or in ear monitors do Dave owners most enjoy?

That's two questions...


Thank you. This is an interesting thread.

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Peter--
 
I am still awaiting delivery of my DAVE but I did have two weeks with it on audition. I think the answer to your first question (Will DAVE spoil you?) is yes and no. Yes, because most of the competition (especially competition that costs less) will not sound as good. You will be aware of this on an intellectual level when listening to other dacs. But no, because eventually our ears adjust and through the magic of hedonic adaptation (look that phrase up), you will still be able to enjoy music. Unless, that is, you have a really acute case of audiophilea nervosa. 
 
Regarding headphones, others on this thread have much more experience than myself. My personal opinion is that the HiFiMan HE 1000 sounds amazingly good with DAVE, better than an unmodified Senn HD 800. But this really gets into personal preference.  

Hi Peter
 
When I'm on the go I can live with the sound from my FiiO X3 II or X5 II, the more so during jogging where adding the Mojo isn't an option. Granted, with the latter I enjoy the music a bit more. My preferred IEM on the go is (what a surprise!) the lowly FiiO EX1 – adequately equalized, it plays on the same level with the Shure SE846 or the IE 800 (which I tend to avoid because of the awful cable – to be replaced soon), it even sounds a bit more spacious and airy and thanks to the low isolation avoids massive occlusion effects.
 
That said, the SE846 with an empty filter tube, equalized, enjoyed on a mild early summer day on the balcony, driven by DAVE sounds supernatural – and about perfect and perfectly musical.
 
On my main system consisting of the FiiO X5II with a nice octave equalizer (with 0.2 dB steps) and DAVE I have one favorite: the HiFiMan HE1000 with a Silver Dragon cable (so far). It needs a bit of EQ corrections to sound at its best, but then leaves no wishes to my ears. I have not the least urge to try any other headphone, although the Stax SR-009 is on my to-do list. But then again, I know how electrostats sound and am quite happy with mine. I don't think I would like it better than the HE1000, since I'm quite sensitive to the inherent sonic flaws of electrostats, as much as I appreciate their virtues.
 
Beside said two electrostats I also like my modified HD 800. Which makes four main headphones I have to choose from before each listening session. Most of the time it boils down to HD 800 and HE1000.
 
Yes, I can still enjoy listening to music through the Hugo – every time I switch back I think it sounds really good. Anyway, DAVE is an even greater step in terms of sound quality and realism than the Hugo was (coming from a McCormack UDP-1 and a Bel Canto DAC2).

My Dave is due at the end of the month. I'm currently using a Hugo which I've had for well over a year (and never plugged a pair of headphones into - sacrilege on this forum). I've been astonished at the sound of the Hugo - utterly moreish - and have gone for the Dave without hearing it. No idea how big an improvement it will be, but I am thinking of buying some headphones - Audioquest Nighthawk.

crgreen said:

My Dave is due at the end of the month. I'm currently using a Hugo which I've had for well over a year (and never plugged a pair of headphones into - sacrilege on this forum). I've been astonished at the sound of the Hugo - utterly moreish - and have gone for the Dave without hearing it. No idea how big an improvement it will be, but I am thinking of buying some headphones - Audioquest Nighthawk.

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No risk at all with DAVE – I've gone the same route.

That's the view I took. Rob Watts is so clearly doing something right with the Hugo that I thought I'd like some more, please.

Fascinating replies; thank you.   Each time a new phrase comes up, I do my homework.   For Rob's posts, it means two of every three sentences must be researched. 
 
As to the EX1 from Fiio.  
 
I am glad I am not alone in thinking I was going crazy.  They are such an amazingly pleasant surprise!  $65 and I have used them jogging (I take Mojo with me on the treadmill).  
 
The headphones issue is interesting because even when just beginning to explore DACs, I needed the ultimate quiet to carefully listen.  
 
I did wonder if enjoying Dave at home meant grabbing a Mojo for exercising as listening to excellence becomes an expectation.  
 
"hedonic adaptation" --I love learning but wondered if this was applicable once the brain becomes accustomed to the high amount of musical data and going to a much lesser amount would be 'dull' or uninspiring.  I do recall Peter Lynch, the Wall Street investor writing that "the day after the world supposedly collapses, people will get up and put their pants on, one leg at a time, and go back to work..."  It is also used in de-sensitizaiton training and to reduce expected trauma.  Fascinating to employ it here! 
 
Thank you, all.  I continue to read up on Dave, your experiences and while researching, I am learning!  

crgreen said:

My Dave is due at the end of the month. I'm currently using a Hugo which I've had for well over a year (and never plugged a pair of headphones into - sacrilege on this forum). I've been astonished at the sound of the Hugo - utterly moreish - and have gone for the Dave without hearing it. No idea how big an improvement it will be, but I am thinking of buying some headphones - Audioquest Nighthawk.

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Congratulations.  It's a big step to buy something as expensive as the DAVE never having heard it but if you like the Hugo, I'm sure you won't be disappointed.  You probably also can't go wrong buying the same headphone that Rob Watts himself prefers but also know that headphones are probably the most personal decision you will make.

What, over choice of life-partner or the like?