Is DEQX a game changer?

An update for those who have been following my progress with the HDP-5: There will be a further delay until I perform the room corrections, due to an unrelated issue that has arisen in my system.

I've recently been noticing significant loss of definition on high frequency percussion, especially on high frequency piano notes. That has not been evident with my Stax headphones, however, just via the speakers. Since the headphone amp is driven by an output of the DEQX, in bypass mode of course, that pointed to my power amp as being responsible. And sure enough, when I lightly tapped on its tubes with an eraser, with the amp powered up, I found that one of its four vintage Sylvania 6SN7GTB's had become highly microphonic.

I have a number of other 6SN7GTB's on hand, but I don't want to use them for anything involving critical listening, such as the room corrections, as I had tried them in the amp a couple of years ago and didn't care for their sonics. So I'm ordering some additional tubes ("tubes" plural, as I'll want to replace the corresponding tube in the other channel with one that matches).

I'm pretty certain, btw, that this issue would not have affected the speaker measurements or speaker corrections I have performed. The problematical tube is only in the path of one channel, and the speaker measurements and correction profiles turned out to be very similar for the two speakers. Also, the tube still measures fine on my Hickok tester, and when I performed the speaker measurements the speaker was considerably further away from the amp than when in its normal position, and was pointed in the opposite direction of the amp.

Best regards,
-- Al

Quite the odyssey Al. Enjoy those new tubes!

And how are you liking the DEQX as a DAC to your headphones, relative to other digital sources you have used with them?

Thanks, Roscoe.

When listening to LPs via the Stax headphones, which are of course very revealing, the DEQX continues to seem to me to be perfectly transparent. Which is amazing, of course, considering the A/D and D/A conversions it puts into the signal path.

With CDs, for which I'm now using the DEQX as the DAC and my Bryston BCD-1 just as a transport, on some recordings it has provided a slight benefit compared to using the BCD-1's analog outputs routed to the Stax headphone amp via tape outputs of my previous preamp (a Classe CP-60), while on others there seems to be little if any difference. I suspect, though, that eventually I'll want to experiment with some different digital cables, and also different cable lengths, between the BCD-1 and the DEQX. I'm presently using an inexpensive Mogami AES/EBU cable, in a 6 foot length.

How has your HDP-4 been working out lately?

Best regards,
-- Al

Al, your experience and comments about the sound difference between the DEQX DAC as compared to your Bryston CDP are consistent with my experience. I thought my DEQX PreMATE was a "squeak" better than my ARC CD-8 CDP, but just a bit.

I too am surprised that the DEQX is as transparent as it appears to be. I agree with your comment that "the DEQX continues to ... be perfectly transparent. Which is amazing, of course, considering the A/D and D/A conversions it puts into the signal path."

Please keep the reports coming.

Regards,

Bruce

User observations about 'transparency' always seem to generate controversy on internet audio forums. People who have not listened to a DEQX corrected system often assert that absolute transparency is not possible with the amount of digital correction taking place.

However, those of us open minded enough to own and use DEQX seem to notice transparency and clarity as some of the most apparent features. Too often, audio equipment is pre-judged by specifications and not by listening.