[Sonnova]

On Tue, 8 Sep 2009 07:35:24 -0700, ST wrote
(in article ):

On Sep 8, 11:11*am, Sonnova wrote:
On Mon, 7 Sep 2009 08:11:42 -0700, ST wrote
(in article ):

3 days ago I decided to hook up my old Theta DS Pro Gen III DAC to my
Marantz SA11s2 just for the fun of it. To my surprise it sounded
better (more to my liking) then SA11s2. Theta used *Motorola 56001s,
30.0000mhz Rubidium clock, PCM63K and AD841 Op-Amp. So my question is
how could an old DAC out perform a new reasonably well designed
Marantz?

Is it possible CD format technology already matured long time ago and
there's nothing new can really improve the sound?

ST

Well, it's a question of the details. I have a 9-year old Sonic Frontiers
DAC
2.6. I've upgraded the OP-Amp in it and added a 96 KHz up-converter and it
sounds better than most CD players, it certainly sounds better than my Otari
professional DAT recorder's built-in DAC, but it's much more carefully made
with better quality parts than those used in most stand-alone players.

Now your Theta, IIRC was a very expensive piece of kit. The Marantz, is also
expensive (My 2009 Music Direct catalog has it priced at $3500) and probably
up-converts standard Redbook CDs to DSD before decoding them (my Sony
XA777ES
SACD deck does this too) and should sound very good, so the difference
between the two is probably a matter of taste on your end. Had you tried
comparing the Theta with all of the SA11s2's switchable noise shaping
digital
filters? You may find one that's more to your liking. I did this with my
Sony
and it's the only digital component I have that doesn't play through my
DAC2.6 (I even play my Apple Lossless Compression files out of my Apple TV
box through the DAC2.6).

About the digital filter I usually select Filter 3 for Cds and Filter
1 for SACD. But sometimes Filter 1 sounds better for certain Cds. But
was just too lazy playing around with filters than listening to music
so I settled for Filter 3 for Cds. Am I hearing less details? I don't
think so. I will get a new Cd which I have not heard before to see
which one got more details.

In the past I tried to upgrade the Theta DAC. Every person I contacted
couldn't find a 30.0000Mhz oscillator clock to upgrade it. By the way
is there a better alternative for the AD841 Op-Amp?

The latest generation of op-amps from National Semiconductor are better than
those available 10-15 years ago. Mostly, the improvements are in
self-generated noise, and slew symmetry. Most older op-amps have asymmetrical
slew - that is to say, the positive going half of the waveform takes a
different (shorter) path through the op-amp than does the negative going
half. Whether or not this is audible is debatable, however, I will say that
no audio designer worth his salt would purposely design a discrete gain or
buffer stage with that characteristic.

ST
p.s This is not to say Marantz SA11s2 is no good. It is just polite.

Again, that just might be taste - for which there is no accounting.