[JaZZ]

After many years of trouble-free use a defect on my Theta Pro basic II has forced me to part temporarily with it. (In the meantime I have to content myself with an old Sony D-99 Discman... that's hard!)

Now I'm speculating how it would compare to one of today's best (passably affordable) DAC's, such as the Chord DAC 64, any lower-priced Wadia or whatsoever. (Its playing partner is/would be the Audiolab 8000CDM transport.)

I'm interested in upsampling, though don't know if it's really indispensable for best (least digital) sound. – How does an Arcam CD 23T compare to the above mentioned combos? It seems to have a high reputation.

Btw: doesn't the Theta – like the Wadias – work with some sort of upsampling, too?

Thanks!

JaZZ

 

[Tomcat]

Have you ever considered DACs that use the minimal interventionist approach of non-upsampling? I have been extremely impressed with the fatigue-free musicality of the latest Audio Note DACs and CDPs. To my ears, the closest digital audio has come to reproducing music and its emotion.

 

[JaZZ]

Tomcat...

...I always thought that the «minimalist» concept of the CD format (just as much resolution [= grid fineness] as neccessary for joe average and technically possible that time) deserves an elaborate approach to reproduction hardware in the form of oversampling (= linear interpolation) and finally upsampling (= sine-function interpolation, as far as I understand). The latter could do kind of imitation of the original (high-res) signal, how it could have looked like if it hadn't to adapt to the 16/44 grid; and thus maybe avoid such ugly filter artifacts as ringing and phase shifts.

Given the new high-resolution formats with their much finer grids are sonically superior, I'm tempted to extrapolate that upsampling could provide a similar improvement, although thus the signal doesn't have any additional information at the disposal (just that from the CD) – it's nothing but an artificial emulation.

So it's not that fun

to see this concept questioned by your experience (which I absolutely take seriously) with such purist DAC layouts. But since the majority of today's highest rated DACs use upsampling as an element of refinement and there are a lot of glowing reviews on them, I have (provisorily) committed myself to upsampling. Unfortunately I can't compare the two worlds by auditioning myself.

JaZZ

 

[Tomcat]

Quote:

Given the new high-resolution formats with their much finer grids are sonically superior

You said you had no chance of listening to Audio Note DACs? That's a pity.

The philosophy behind the non-oversampling, non-re-clocking and digital-filterless approach is that time smear and ringing effects are musically far more serious than any bandwidth limitation and best dealt with by processing the signal as little as possible because any attempt of improving the signal beyond the resolution of its format will cause signal degradation in the time domain and is a cure worse than the disease. And indeed, to my ears, Audio Note DACs excel at timing, the reproduction of low-level signal content, the phrasing and decay of a note, at timbre, ambience, body, dynamics and musical flow. And they do this in the least fatiguing fashion I have ever experienced in digital reproduction.

By the way and as far as I know, the stand-alone Audio Note DACs will handle a 24 bit/96KHz encoded signal coming from a DVD transport just as well as they handle a digital signal from a CD transport.

 

[JaZZ]

Quote:

The philosophy behind the non-oversampling, non-re-clocking and digital-filterless approach is that time smear and ringing effects are musically far more serious than any bandwidth limitation...

I agree completely. But time smear and ringing are identical with bandwidth limitation! I guess the audio note way is similar to the classical Wadia filter ideology and accepts the 3.5 dB roll-off at 20 kHz. For no filter means to use the signal as it is: with its inherent – amplitude modulated! – high-frequency roll-off. Certainly not the worst solution to minimize ringing and phase shift. The main obvious downside: HF signals charging tweeters thermically.

I'll keep Audio Note in mind. What bothers me a bit: the high output impedance of 1500 ohm – not ideal for my passive pre. The plus: the 6DJ8 output tubes of which I already have a small collection because of my EMP (at the moment with the same tubes as yours: Telefunken ECC801S and Philips E88CC Miniwatt SQ).

 

[Tomcat]

Quote:

But time smear and ringing are identical with bandwidth limitation!

JaZZ,

yes, I guess if we could increase bandwidth and sampling frequency at will, up to 500 KHz or 1 MHz, we might be able to forget about time domain issues.

It's interesting that we came to the same conclusions in regard to NOS tube rolling in the EMP. I wonder what the more expensive Amperex 6922 and 7308 would do in its output stage, or the Siemens Halske CCa. Have you ever tried any of those? And what have been the tubes you didn't like?

 

[JaZZ]

Tomcat...

...I've sent you a PM.