[tkteo]

Came across this article on switching power supplies versus linear power supplies.
http://benchmarkmedia.com/blogs/application_notes/152143111-audio-myth-switching-power-supplies-are-noisy

 

[paulchiu]

  Came across this article on switching power supplies versus linear power supplies.
http://benchmarkmedia.com/blogs/application_notes/152143111-audio-myth-switching-power-supplies-are-noisy

 
This stuff is not getting enough press over the years.  It cost money to shield transformer from the nasty stuff.
Kudos to Chord for the great design in the DAVE, especially in the power section.
 
Paul

 

[Sunya]

Rob, could you tell how Dave gets the extra 6 dB of gain in preamp mode vs the DAC mode? Is Dave running with 6 dB of digital headroom (max output at -6dBFS) in DAC mode?

 

[Rob Watts]

   
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).
 

 
I started to reply to this, and turned it into a blog post, as it got a bit long!
 
See here: http://www.head-fi.org/t/800264/watts-up/120#post_12586725
 
Rob
 
 

 

[Rob Watts]

  Rob, could you tell how Dave gets the extra 6 dB of gain in preamp mode vs the DAC mode? Is Dave running with 6 dB of digital headroom (max output at -6dBFS) in DAC mode?

The display setting of -3dB in DAC mode is the same as pre-amp mode - its just the volume control is permanently set to -3dB.
 
Dave has inbedded overload margins, for lots of different reasons, so it will actually only clip at volumes above +4dB. -3dB is 3v RMS, +4dB will give 6.7V RMS from the headphone or RCA outputs.
 
Rob

 

[Sunya]

If the volume is set at -3dBFS in DAC mode, how can it go to +4dB? Shouldn't 0dBFS be maximum output or 4.23V from RCA?

 

[Crgreen]

Just been informed my Dave is arriving this week, earlier than expected. Hurrah!

 

[esimms86]

Go to this link and scroll down to the first video. It's nothing earth shattering but you at least get something of the feel of being in the Chord room with DAVE at Munich.
 
http://www.computeraudiophile.com/content/700-images-munich-high-end-2016-part-1-3/

 

[romaz]

   
This stuff is not getting enough press over the years.  It cost money to shield transformer from the nasty stuff.
Kudos to Chord for the great design in the DAVE, especially in the power section.
 
Paul

@tkteo, now you're going to make Paul more paranoid than he already is.
 
Paul, I think it's time to get one of these:
 
http://www.pksafety.com/dupont-reflector-suit.html?gclid=COa9nOzG4cwCFU1gfgodzZIB7w

 

[paulchiu]

  @tkteo, now you're going to make Paul more paranoid than he already is.
 
Paul, I think it's time to get one of these:
 
http://www.pksafety.com/dupont-reflector-suit.html?gclid=COa9nOzG4cwCFU1gfgodzZIB7w

 
Thanks Roy!
 
Just ordered 3, for the family.
 
Paul

 

[Crgreen]

Dave arrived and installed, running through its balanced outputs. Beautifully liquid sound with much better grip and control than the Hugo, and enormous dynamic range. It's been running for about 24 hours. What's the usual burn-in time?

 

[lovethatsound]

Dave arrived and installed, running through its balanced outputs. Beautifully liquid sound with much better grip and control than the Hugo, and enormous dynamic range. It's been running for about 24 hours. What's the usual burn-in time?

congratulations on getting your dave.burn-in time around 600 hours I'd say.Enjoy your music

 

[Crgreen]

If so, thank goodness it sounds this good after 24!

It's a lot of money, but I'm now thinking of it this way - I've just acquired a new music collection.

 

[Peter Hyatt]

Dave arrived and installed, running through its balanced outputs. Beautifully liquid sound with much better grip and control than the Hugo, and enormous dynamic range. It's been running for about 24 hours. What's the usual burn-in time?

Congratulations!
 
Oh, how your description makes me want to hear my favorite recordings through DAVE!  
 
"Beautiful liquid sound" and "enormous dynamic range"!

 

[STR-1]

Dave arrived and installed, running through its balanced outputs. Beautifully liquid sound with much better grip and control than the Hugo, and enormous dynamic range. It's been running for about 24 hours. What's the usual burn-in time?

I now face running in my second Dave. Mine finally arrived today after living with a loan Dave for six weeks. I can't remember with the loan (which only had about five hours use before I got it) how long it took to reach the point when it stopped improving but I'm sure it was over 200 hours.