CHORD ELECTRONICS DAVE

[ubs28]

I don't believe in the Chord Blu MKII technology which is why I will never buy it. A SD card can hold much more content than a CD at much higher quality also.

I will only consider a Chord Blu MK3 if it has SD playback (hopefully multiple slots so the Blu MK3 can hold let's say 2 TB of high-quality audio for example) and streaming technology.

And since SD playback supports higher than 16-bit, why not add more than 1 million taps to take advantage of 24-bit audio?

 

[flyte3333]

I have finally gotten round to listen to the AQ jitterbug, as a quest to understand where the RF noise problems from the source was coming from - via the mains or the USB.

Firstly - very much - YMWV as RF noise is a funny thing and source noise may affect other parts of the system, so the findings here may well be different in other circumstances.

So I did the tests with just a Win 10 lap-top (jRiver), Dave and pair of Nighthawks, in a hotel in Singapore. The idea was to try to evaluate whether the SQ improvements I heard when disconnecting the lap-top from mains and running off battery was from the USB connection or via the mains supply. Now Dave is galvanically isolated from LF and RF noise, and this makes a huge difference in SQ. But the galvanic isolation is not perfect as there exists a 2pF coupling capacitance. Now you may think 2pF is nothing to worry about; but at 1 GHz it is nearly 80 ohms impedance, so RF noise in the GHz will couple through - and I know that GHz noise is significant in causing noise floor modulation and hence changing the sound quality.

I used my design lap-top, an MSI Intel i7 machine, as it will be noisier than my music lap-top (HP Pavilion) which is very power efficient. This is so it would be easier to hear any changes.

So adding the Audioquest Jitter Bug did indeed improve SQ - it was fairly easy to hear it, with it sounding smoother, warmer, with less sibilance and glare. Instrument separation and focus was better. These are exactly the kind of change I hear with lower RF noise, so it was not unexpected.

Next was to do the listening test with the lap-top on batteries - and then it became impossible to reliably hear the effect of the jitter bug. Additionally, the improvements heard were much smaller with the jitter bug connected when you disconnect the lap-top power. Here is a rough assessment of SQ performance with 100% for best, 0% for worst:

Lap-top battery power, no jitter bug 100%
Lap-top battery power with jitter bug 100%
Lap-top mains power with jitter bug 75%
Lap-top mains power no jitter bug 0%

So what does this tell us? Basically the most significant path of RF is residual coupling via the USB, not via the mains supply as the jitterbug alone gets you most of the way.

Use the jitter bug for mains powered USB sources - it is worth the small cost.

The best sound is still with a Win 10 lap-top on battery and for critical listening that is what I do. Battery operation and Dave's galvanic isolation means effectively perfect RF noise isolation from the source.

Note also Win 10 is technically better than iOS xx, Android or Linux as these driver less USB's do not guarantee bit perfect data at the DAC; but Chord's Win driver does resend faulty packets, so we can guarantee bit perfect data for Dave. It would be interesting to do a listening test of driver less against Win.

Rob

Hi Rob

I'm guessing your laptop , when plugged into mains power, is not grounded?

Have you heard a small improvement using Dave's USB input by grounding your laptop's PSU? Of course it won't better running off batteries but does grounding the PSU improve SQ when connected to mains power?

Does grounding a laptop defeat the USB galvanic isolation of Dave, since Dave's PCB is also grounded?

Cheers

 

[Rob Watts]

Actually the MSI laptop PSU is grounded, and my office system has lots of things attached to the laptop, so there are lots of ground loops. A Dave with battery powered laptop with everything disconnected does sound better; but it's the kind of change you hear only by careful AB listening; in practice it's too small a difference to worry about.

 

[doraymon]

@Rob Watts: I'm still considering which ferrite chokes are best to be put on the USB cable connected to DAVE to reduce RF noise.
Have you got any clue which frequency range is the most important?
I understand it depends on the surrounding environment and I'm ready to experiment but a solid starting point would help me make an "educated first attempt".
Thanks.

 

[miketlse]

@Rob Watts: I'm still considering which ferrite chokes are best to be put on the USB cable connected to DAVE to reduce RF noise.
Have you got any clue which frequency range is the most important?
I understand it depends on the surrounding environment and I'm ready to experiment but a solid starting point would help me make an "educated first attempt".
Thanks.

The Blu2 thread has some posts for this topic as well.
https://www.head-fi.org/threads/cho...official-thread.831343/page-190#post-14095563
https://www.head-fi.org/threads/cho...official-thread.831343/page-190#post-14095640
https://www.head-fi.org/threads/cho...-official-thread.831343/page-98#post-13705284
https://www.head-fi.org/threads/chord-electronics-dave.766517/page-627#post-13881243
https://www.head-fi.org/threads/chord-electronics-dave.766517/page-629#post-13889772
https://www.head-fi.org/threads/chord-electronics-dave.766517/page-627#post-13882837

 

[doraymon]

The Blu2 thread has some posts for this topic as well.
https://www.head-fi.org/threads/cho...official-thread.831343/page-190#post-14095563
https://www.head-fi.org/threads/cho...official-thread.831343/page-190#post-14095640
https://www.head-fi.org/threads/cho...-official-thread.831343/page-98#post-13705284
https://www.head-fi.org/threads/chord-electronics-dave.766517/page-627#post-13881243
https://www.head-fi.org/threads/chord-electronics-dave.766517/page-629#post-13889772
https://www.head-fi.org/threads/chord-electronics-dave.766517/page-627#post-13882837

Thanks a lot for this!
Some of the posts I had already found, some not.
So a good guess would be 300MHz to 1GHz.
On the same point I still haven't understood well if the ferrite cores would filter the RF noise coming from the computer's power supply or that coming from the surrounding electromagnetic fields (antenna effect on the USB cable)? Or both?
I assume both provided the cores offer high impedance at the given RF frequency.

Apologies if this has been already discussed before, I'm just trying to have a structured approach to the issue so to avoid spending a fortune in random guessing...

 

[Jawed]

Ferrites are always going to be random guessing. There are no measurements to back up any reports of what works best with DAVE.

You should always use the optical input on DAVE as the reference for your experiments with other inputs, or with USB spaghetti or adding ferrites to electrical cables. Add ferrites until you can't hear any difference between this electrical configuration and optical.

If you think your non-optical setup sounds better than optical, then there's something else wrong in your system, as optical is the way DAVE is supposed to sound.

I also recommend lots of ferrites on DAVE's mains cable.

Now playing: Wolf Alice - Song to the Siren

 

[Rob Watts]

@Rob Watts: I'm still considering which ferrite chokes are best to be put on the USB cable connected to DAVE to reduce RF noise.
Have you got any clue which frequency range is the most important?
I understand it depends on the surrounding environment and I'm ready to experiment but a solid starting point would help me make an "educated first attempt".
Thanks.

My tests with ferrites on usb had no change at all... But of course that does not mean your situation would be the same. The situation with blu2 is very different, and not applicable to usb; the chip ferrites that I use on the hugo 2 were 300 MHz types, and this for sure with headphones eliminated the issue, as optical sounded the same as usb. So give 300MHz types a try, but do not be surprised if it makes no difference at all.

 

[ray-dude]

My tests with ferrites on usb had no change at all... But of course that does not mean your situation would be the same. The situation with blu2 is very different, and not applicable to usb; the chip ferrites that I use on the hugo 2 were 300 MHz types, and this for sure with headphones eliminated the issue, as optical sounded the same as usb. So give 300MHz types a try, but do not be surprised if it makes no difference at all.

As one of the people that posted about ferrites making a huge difference on USB (to say the least), I want to emphasize that when I was connecting USB directly to DAVE, I heard essentially no difference with ferrites (in my narrow experience, DAVE USB is the Chuck Norris of inputs...ferrites wrap themselves in USB cables when they see it).

In my setup with my digital source and the cables I was experimenting with, I heard a huge difference when connecting to the USB input of the Blu2 (and then to DAVE) vs the CD of the Blu2, which cleaned up quite nicely with Topnisus ferrites (impedance curves unknown) on my USB cable.

All that being said, to Rob's point, noise is a system issue, which makes every system (and room and neighborhood and building) different. However, these are very inexpensive experiments to try, and see if there is a difference in your particular corner of audiodom (post what you find!)

 

[doraymon]

My tests with ferrites on usb had no change at all... But of course that does not mean your situation would be the same. The situation with blu2 is very different, and not applicable to usb; the chip ferrites that I use on the hugo 2 were 300 MHz types, and this for sure with headphones eliminated the issue, as optical sounded the same as usb. So give 300MHz types a try, but do not be surprised if it makes no difference at all.

Great thanks.
I will see if I find a proper one from Würth.

 

[doraymon]

All that being said, to Rob's point, noise is a system issue, which makes every system (and room and neighborhood and building) different. However, these are very inexpensive experiments to try, and see if there is a difference in your particular corner of audiodom (post what you find!)

Yeah well, inexpensive relatively to the DAVE...
Sure I will report back.

 

[dcguy73]

I heard the Chord DAVE, the Blu MK2, and the HE1000v2 together at a local meet this weekend...and I am forever ruined for it. The sound was incredible, unbelievably palpable and life-like, the best I've ever heard with the HE1000v2. My much more modest gear now sounds like a low-end Bose system. Now all I have to do is win the lottery and I'll be set. It's a good thing I don't have kids, because they would no longer have a college fund at this point.

 

[Whitigir]

I heard the Chord DAVE, the Blu MK2, and the HE1000v2 together at a local meet this weekend...and I am forever ruined for it. The sound was incredible, unbelievably palpable and life-like, the best I've ever heard with the HE1000v2. My much more modest gear now sounds like a low-end Bose system. Now all I have to do is win the lottery and I'll be set. It's a good thing I don't have kids, because they would no longer have a college fund at this point.

I would think Susvara + MSB Select DAC and MSB amp would be your answer when you win the lottery

 

[Thenewguy007]

Actually the MSI laptop PSU is grounded, and my office system has lots of things attached to the laptop, so there are lots of ground loops. A Dave with battery powered laptop with everything disconnected does sound better; but it's the kind of change you hear only by careful AB listening; in practice it's too small a difference to worry about.

Wouldn't a good UPS with the Dave do the same thing for people on PCs?

 

[ruthieandjohn]

Chord DAVE newbie question...

How does one actually purchase a Chord DAVE in the US? Online (to Chord Electronics)? From “local” Chord distributor (nearest shon on Chord site is 200 miles away and only gives voice mail on answer during business hours).

What is the current price?

Thanks!