Best opamp for I/V conversion? (DAC)

[carlosfm]

Originally posted by Gordon McGregor
Carlos, I prefer SACD multi-channel or DVD-A Advanced resolution to any CD, even to any HDCD, sorry about that ...

If you can find decent recordings and a decent player (not common), that's fine.
I've heard some "high-end" SACD players and I was shocked.
And playing CDs, forget it.
It was not a Krell Standard, but a Sony SCD-1.
DVD-A is only good at outrageous prices, and most discs are too badly recorded.
I'll wait some time (years? ) more.

Anyway, what I really really like is vinyl.

[Elso Kwak]

Originally posted by carlosfm


If you can find decent recordings and a decent player (not common), that's fine.
I've heard some "high-end" SACD players and I was shocked.
And playing CDs, forget it.
It was not a Krell Standard, but a Sony SCD-1.
Anyway, what I really really like is vinyl.

Hi Carlos,
To me it seems that the new medium is even more clock sensitive than redbook CD. Tried several clocks in the Sony SCD-1 of a friend of mine.......(Lcaudio, Tent, KC-7, KC-8).
In original state the Sony did not impress me either.

[carlosfm]

Originally posted by Elso Kwak
In original state the Sony did not impress me either.

Maby it's the 1-bit thing.
That is, transform 1-bit DSD to 5-bit Delta-Sigma (as most dacs today), noise shaping, all those artifacts.

[robbie b]

The same as I do, and I got the same feelings with OPA627 ... but I use M&K 150THX speakers+M&K 350 MkII sub. What speakers do you use?

Gordon, I listen to a Dynaudio Confidence 5. Powered by a modified 200 Watts 4 ohms, DUSON amplifier, this is a high biased classAB amplifier which has been modified by me.

Thanks for your wish, Rob. The best stuff to use for recording, as anyway we need to analyze the signals in PC, is to use good soundcard such as Lynx L22, Two B or E-mu 1212M/1820M. I hope that sometimes we will be able to record and compare oversampled and non-oversampled DACs to finish the discussion ... or at least to have more or less objective listening evaluations.


Sorry but I check my soundcard and its a pityful Soundblaster 64 with a noise level of about -70 dB with spikes around -55 dB.
So I think my equipment is not good enough.


Nevertheless I 'm looking to find something better.

Good luck

Rob

[Elso Kwak]

Originally posted by carlosfm


Maby it's the 1-bit thing.
That is, transform 1-bit DSD to 5-bit Delta-Sigma (as most dacs today), noise shaping, all those artifacts.

Carlos,
It is the CLOCK!

[carlosfm]

Originally posted by Elso Kwak

Carlos,
It is the CLOCK!

Yes!
But with a good clock will that thing match a good CDP on CDs?
Will the clock make anything better for that "bland", sooo soft, sleep inducing sound, even on SACD?
It will make things better, of course, mainly that flappy bass that spoils everything else...
I guess good "universal" players will never exist.
Hey, some people like this kind of sound, but not me.

I only heard a "universal" player that told me something, actually on every format I heard good sounds indeed.
The Linn Unidisk.
But it's sssssssso expensive.
BTW the CD12 is superior (on CDs, of course), but not by a large margin.

Who wouldn't like to have a good "universal" player?
I would.
I'll wait sometime more, can't find much of the music I like on these "high-resolution" formats, anyway.

[Gordon McGregor]

There are many myths around the new formats. For example, Yamaha 2300 and 2300MkII uses AD1955 DACs and OPA2134 ONLY for SACD (DSD), and for PCM signals it uses 8-channel codec PCM1608 with NJM4558 ... interesting?
I liked vinyl as well, till the new formats became to be good enough. Look, we had A LOT of SACD stereo, upsampled/upconverted from CDs and edited in PC Tools with double convertion to PCM and back to DSD ... we had a LOT of DVD-A 24 bit 48kHz and even some 20 bit 48 kHz ... But now, when we have professinal re-mastering (as for example, in DSotM multi-channel tracks) and even correct recordings and editing for DSD using SADiE (based on E-chip approach), and Advanced resolution DVD-A (24/96kHz multi-channel tracks) the situation is different. We also have UNIVERSAL DVD/SACD/CD players, as for example DV-47Ai (DV-757Ai in Europe) or DV-59AVi (DV-858AVi in Europe), which are used just like transports - equal to DVD-ROM or CD-ROM in computers. i-link is working in jitterless mode (AV/C Command Set for Rate Control of Isochronous Data Flow 1.0 protocol) here is a good link with important information how it works ... http://www.avsforum.com/avs-vb/showt...27#post2874627
In few words the data buffer in a receiver is filled with the different speed to avoid the buffer overflow. DACs in the receiver use the same clock, as used for getting information from the buffer.
The DSD stream is processed by the correct way as well. They use DSD->PCM converters SM5816 or in newer models of receivers SM5819A with -130dB Digital filtration (2FS), therefore we almost have no intermodulated noises in the audible range due to high level of digital noises in DSD signal. Then we have DF1704 in the receiver, working at x8 oversampling (x4 for 192 kHz signals) with PCM1704 DACs ... the path is similar for all PCM and DSD signals (except of the DSD->PCM converter).
The result is here http://members.cox.net/alex_lat/Tests/Taylor.JPG - the same James Taylor "Hourglass" SACD "Line 'Em Up" song ... one through analog filters in PCM1738 (so called "correct" SACD decoding with the shortest path) and another one - through DSD->PCM convertion and multi-bit DACs ...
What is interesting, Sony in their new STR-DA9000ES receiver (through i-link) uses the same SM5819A DSD-PCM converters and futher PCM processing ONLY!
With replacement of op amps in I/V and LPF stages in the receiver we got very good path without significant expenses or a lot of DIY work ... and we can process ALL formats by almost the same way with lowest level of jitter (dependent of the jitter in the receiver's clock, but it is not that bad - they use quite good quarts oscillators http://members.cox.net/alexhardware/images/quartz.JPG ) and in 59TXi service manual, for example, even provide the clock flow paths, therefore it is easy to be sure that the clock is good enough. With a bad clock we couldn't get -120dB noise background as well (as we can see on the picture), actually.
Even for CDs the above mentioned path works quite good, taking in consideration the jitterless i-link transmission with AV/C flow control on (it called PQLS in Pioneer, HATS in Sony).

Gordon, I listen to a Dynaudio Confidence 5.

Rob, are you OK with 47Hz in them? For me it is not enough, especially for SACD and DVD-A ... M&K MX-350MkII is able to produce 23 Hz at -3dB and:

M&K's Deep Bass sealed-box design produces significant deep bass output,with an in-room response flat to frequencies well below 20 Hz. Many other THX subwoofers have vented cabinets, giving them an extremely sharp rolloff (24 dB/octave or more) below the lower limit of their "flat" response. By reproducing bass frequencies lower than 20 Hz, the MX-350THX has a lifelike power and authority that these other subwoofers simply cannot match.

It is the same in comparison with floor-standing speakers which use ported cabinets ... IMO this is one of the reasons of non-successful start for the new formats.
We can have a long thread about the phase distortions above and below the resonanse point in Helmholtz resonators (i.e majority of the ported speakers) but it is an other story.

Sorry but I check my soundcard and its a pityful Soundblaster 64 with a noise level of about -70 dB with spikes around -55 dB.
So I think my equipment is not good enough.

Well, I have to admit that you are right here

Nevertheless I 'm looking to find something better.

I got my Lynx L22 on ebay for 50% of the retail price, but even with this price it is too expensive to be used as a regular soundcard. As a good alternative solution I can recommend E-mu 1212M for $199 (you can find it even for $170 sometimes) ... it is a good soundcard using CS4398 modern DACs; you can replace JRC2068 op amps in it to good ones, that will make it unbeatable at this price level. Here are the results of it's measurements:
http://www.fixup.net/products/benchmarks/1212m2448.htm

[fmak]

[QUOTE]Originally posted by Elso Kwak
[B]
Hi Carlos,
To me it seems that the new medium is even more clock sensitive than redbook CD. Tried several clocks in the Sony SCD-1 of a friend of mine.......(Lcaudio, Tent, KC-7, KC-8).
In original state the Sony did not impress me either.

------------------------------------------------------------------------------------
It's not the SCD1 but your system!!!!

The Tent clock doen't actually do much for the SCD! and this has been confirmed by Allen Wright.

[carlosfm]

Originally posted by Gordon McGregor
There are many myths around the new formats. For example, Yamaha 2300 and 2300MkII uses AD1955 DACs and OPA2134 ONLY for SACD (DSD), and for PCM signals it uses 8-channel codec PCM1608 with NJM4558 ... interesting?

What a stupid thing to do.
These days many dacs accept both formats and that's what most players use.
If they want to make things separated, at least use decent components.

Anyway, I'll wait some time more.
I don't have the money right now for a Linn Unidisk.
Pioneers and Denons and Sonys just don't convince me.
Maby I diy something.

[Gordon McGregor]

Originally posted by carlosfm
Anyway, I'll wait some time more.
I don't have the money right now for a Linn Unidisk.
Pioneers and Denons and Sonys just don't convince me.
Maby I diy something.

Not reasonable, IMO. You can use any of them (they have good DSPs, power supplies, etc.) , except of Sony as it doesn't support DVD-A - you can DIY something using those devices, it will save A LOT of time for you.
High end equipment as Linn UniDisk use the same components no reason to pay THAT much if we have some cheaper "Lego sets", manufactured by Pioneer, Denon or Yamaha ... etc.