Chord Qutest

[buonassi]

Here, Rob talks about the noise floor modulation and how it is also present in amps, conductors (wires), etc.  I have to say, I recently heard mojo with my favorite IEMs at a meet in Chicago earlier this month, and was very impressed.  So much so, I'm considering the qutest, or a second hand 2qute at half the price.....

 

 

 

[buonassi]

good points, thx.  I think I'll try and nab a qutest. The overwhelming feature for me is the variable voltage output.  I did wonder about the 2qute possibly clipping at least one of my headamps.  This way, I can lower the voltage without having to use digital volume control.  

 

Thanks @ecwl..... I think you helped me make up my mind.  This will be a big milestone for me.  The most expensive gear I own (besides some of my in ears - which are ridiculously priced btw) is a metrum amethyst.  I'm trying to find a way to justify keeping it if I get the qutest.  That NOS sound is special, though not as detailed as a very good linear phase DAC.  I was considering the ADI-2 DAC, but I really don't need all those features.  

 

The qutest seems to be, by all accounts, and Darko's words "The DAC to beat at 2k".  pretty sure I can get one used for $15-1600.  But they don't last for more than a day after being listed on head-fi.  I have to be quick.  I'll report back after the score!

[buonassi]

@Miska, I have a few questions for you.  

 

1) Are all of your interpolation filters 'sinc' ?  I'm pretty sure at least a few are.  I don't have your software because I use AU plugins - otherwise, I'd be all about it.  The sinc is what Rob Watts goes on and on about.  That, and the noise floor modulation. 

 

2) I've had very good experiences upsampling in A+ using iZotope and Sox feeding my metrum amethyst, but have no idea what type of interpolation they use (cubic, sinc, etc).   Do you know?

 

3) I have to believe that your filters, being processed in the computer, contribute to lower noise floor modulation in the DAC.  Would that be a correct assumption?  And the fact that they use many more taps than the Qutest may contribute to better reconstruction of the original waveform (at least theoretically)? 

 

 

[buonassi]

Thanks @Miska.  A very helpful response.  I now know more than I did yesterday!  

 

When I had an SD Dac, I did rather enjoy PCM>DSD conversion prior to sending to the DAC.  I was was floored by a DSD128 original file I got from Blue Coast sampler/test download.  So, I may have to revisit conversion to DSD once again.  I really should've kept that iFi iDAC2 🤦‍♂️

 

I realize your position on AUs and how it doesn't quite fit with your value prop for HQP.  I am still intrigued by your player and may get it to use with my upcoming 2ch setup.  It'll be modest hardware to start (some passive KEFs and an amp yet to be decided).  

 

Is anyone here using their Qutest with DSD?  Any thoughts on how it handles DSD vs PCM?  

[buonassi]

well there goes that thought.   I guess the lesson here is to avoid as many format conversions in the chain as you can - feed the DAC what it processes natively.  If a conversion must take place, do it with the best tools you can.  IE HQP, etc.  

[buonassi]

30 minutes ago, skatbelt said:

With any Chord DAC, it is best to feed it with the native resolution of the source and let the WTA filtering do the trick. That's what makes them unique.

 

I'm getting some interesting results using one round in software (44.1 > 88.2), then allowing the 2Qute (not the Qutest YET!) to continue using the Watts filters to oversample.  I say 'interesting' because I haven't really critically evaluated it yet.  But there's no law prohibiting a hybrid approach.

 

Ultimately, you're right.  When you buy a chord DAC, the filtering is one of their differentiators.

 

What really got my attention was that a straight hookup to my mac using USB didn't sound bad, like other DACs I've owned.  Dare I say it sounds even a little more full and 3D than the BNC.  Anyway, the plan is to use 2Qute as a proving grounds, then I'll drop some coin on the Qutest if I still like this presentation after a month or so.