[jb]

In this review Miklorsmith said he didn’t have a preference between the Altmann Attraction and LessLoss 2004 DACs except that he would choose one or the other depending on which amplifier he was using. What I get from that is the two DACs are identical in regards to distortion, resolution, dynamics, and all the other audiophile attributes. I find that hard to believe. As I see it, the two DACs couldn’t be more different.

Just look at the datasheets. The TDA1543, used in the Altmann Attraction, is described as a “Dual 16-bit DAC (economy version).” Why “economy?” Philips compromised the design to reduce manufacturing costs. Read the specs. THD+N = -75 dB. That spec is typical for a 13-bit DAC. The ‘1543 throws away almost 20% of the low-level information on the CD! In this thread I showed the poor settling performance of the ‘1543. Here is a spectral plot of a 0dB, 1KHz sine wave. The extra peaks represent noise and distortion. (The spectral plot shows the frequency and relative amplitude of each component in the audio signal. A good DAC produces a single peak at the signal frequency, like this.)

It’s unclear whether or not the Attraction DAC includes an anti-alias filter; most other TDA1543 NOS DACs do not. Aliasing is audible as high frequency, enharmonic overtones. Without the filter, what are essentially square waves are sent to your amp and speakers, which can lead to phase distortion and lots of other problems. Many audiophiles confuse phase distortion with increased sound stage. They are not the same.

On the other hand, the PCM1704, used in the LessLoss, is described as a “24-bit, 96KHz Sign-Magnitude DAC.” It is a much more sophisticated and costly design. The lowest grade chip has THD+N = -92dB, which is about par for a 16-bit DAC. That’s not so good for a 24-bit DAC but at least it’s not throwing CD bits away. Too bad LessLoss coupled the PCM1704 with a DF1706 digital filter. Digital filters are good at interpolating steady-state sine waves, which is what sampling theory is all about, but digital filters suck the life out of the music. Because I don’t have a DF/PCM1704 DAC handy, I’ll look at the output of two highly rated DACS with built-in digital filters, AKM and Wolfson.

Here is a 0dB sine wave eight octaves below the Nyquist frequency. The green trace is the AKM and the yellow trace is the Wolfson. Here is the same signal as a two cycle burst. This is what the signal should look like. Pre- and post-ringing is characteristic of digital filters. The post-ringing of the Wolfson is excessive. With both DACs, the frequency of the ringing is not related to the frequency of the signal and will be particularly obnoxious.

Here is a one octave warble centered eight octaves below the Nyquist frequency. The AKM does a passable job but the Wolfson is all over the place. Notice the low frequency modulation and the forked peaks of some of the cycles. Digital filters just don’t do well with abrupt changes in the signal. Unfortunately, music is all about abrupt changes. Even the simplest melody starts, stops, and changes from one note to the next.

[miklorsmith]

Rather than answer my legitimate questions to your half-baked, shotgun comments in the original thread, you've chosen to start another with the same title attacking same products and my review based on supposition and half-baked theory.

Nice, very classy.

[jb]

Rather than answer my legitimate questions to your half-baked, shotgun comments in the original thread, you've chosen to start another with the same title attacking same products and my review based on supposition and half-baked theory.

Where have I "attacked" any product and where have I “attacked” your review? I'm just pointing out the facts of life and my "half-baked" theories apply to every TDA1543 NOS DAC and every DAC with a digital filter. I just used your recent rave review of those products as a starting place. I'm amazed you didn't notice a significant difference between those two DACs, or if you did, you certainly didn't communicate what each DAC sounded like in a meaningful way.

The briefest synopsis would be to say the Altmann is a nonoversampling DAC which adopts extension and resolution from the oversampling crowd and the Lessloss is an oversampling unit, borrowing the relaxed ease of presentation from the NOS group.

The 16-bit, 44.1k Altmann, with only 13-bits of effective resolution, matches the extension and resolution of the 24-bit, 352.8k LessLoss? OK, if you say so. And the LessLoss has a presentation similar to a NOS DAC? How is that possible? The sole reason for the "relaxed ease" you hear is the absence of a digital filter, and there is no avoiding the very-dated, first-generation digital filter in the LessLoss.

As to which is better, it depends on which direction your system needs help. If you're running all solid state gear and wish for some tubed warmth, I'd guess the Altmann would be better. If the system is softer and needs punch and vigor, the Lessloss is probably the ticket.

I have nothing more to say about your non-review. I started a new thread in the hopes of beginning a slightly more technical discussion about the faults and foibles of digital audio. I'm thinking about spilling the beans on asynchronous resampling, but that would probably outrage the crowd that is drooling over the Prometheus DAC.

[miklorsmith]

If you conclude I thought the DACs sounded the same, please re-read what I wrote.  I understand why you might not understand what I wrote - the comparisons need a little background about how the camps sound.  If you know more about designing digital equipment than the designers, go beat 'em and make some money for your efforts.

You haven't heard either of these pieces, obviously.  I think you should start a new "Theoretical Design Musing" forum and take your armchair engineering over there.

When you have something positive to contribute here, maybe post # 16 could be a contribution to society.

If you're truly interested in technical discussions, folks over at The Lab may be able to indulge you.

[anubisgrau]

jb, would you mind sharing with us what commercially available DACs you consider to be worth of an audition, audiophile attention or simply - a purchase?

thanks.

[richidoo]

And to think - all along I thought Altmann WAS using the TI chip, because he offers 24 bit option. I didn't know the older Philips could do high res. I read the hell out of 1704, thinking it was in the Altmann.  Lessloss is just too expensive for me, and the Altmann even with JISCO turned off and stock SB as transport sounded plenty good enough. Lessloss website is an interesting read though. Both camps obviously know their stuff. But only one uses tubulator goo. 
Rich

[anubisgrau]

technically altmann may be a big voodoo, but it sounds better than any digital i've heard. it's beyond my understanding what sounds so good there and that's why i always love to hear what people who dislike altmann consider to be a good or a better sounding DAC.


edit: can 1543 be re-programmed before an implementation?

[jaspal kallar]

And to think - all along I thought Altmann WAS using the TI chip, because he offers 24 bit option. I didn't know the older Philips could do high res. I read the hell out of 1704, thinking it was in the Altmann.  Lessloss is just too expensive for me, and the Altmann even with JISCO turned off and stock SB as transport sounded plenty good enough. Lessloss website is an interesting read though. Both camps obviously know their stuff. But only one uses tubulator goo. 
Rich

So with the JISCO on did it make a big improvement?

   jaspal.

[richidoo]

So with the JISCO on did it make a big improvement?
   jaspal.

I couldn't hear it. I don't think anyone listening did hear it. We weren't listening with microscope though.

Equipment first test was: SB3 > Mike's digital cable>Mike's DAC (red top batt)> Grover S 1 Meter (latest white)> ARC Ref1>Grover S>Snappers> Anticable SC> Focus2020.

Equipment 2nd test: Oracle CD1000 transport> Mikes digicable (JPS IC was too heavy for the pine board 'chassis' >DAC(red top)> Grovers (again JPS too heavy) > AR pre > JPS ALuminata SE ICs> Snappers > Aluminata speaker wires>Focus2020. Much better sound, still no detectable difference with jisco.

I have a stock Samsung HD-841, I should have tried it as transport to test the JISCO, but I was cooking burgers for 10 hungry audiophiles. hehee What a fun night. Wow that DAC is awesome. Thanks again Mike

I haven't heard many high end digital players, but this sounded much better than my stock SB, that's for sure. Other with more experience agreed it sounded very good.
Rich

[Gordy]

So with the JISCO on did it make a big improvement?

   jaspal.

I could hear no improvement using Jisco when using an Olive HD feed to the dac but, when Natureboy and I used an Oppo 940 as a transport there was an increased clarity in fine/micro detail.  IIRC Natureboy referred to it as an increased midrange clarity and I interpreted it as more of an image density.  Definitely worth getting if you're using a less than SOTA CDP or a DVP.  Probably not necessary with HD sources. If I'm ever in the position to be able to purchase an Altmann, I'll probably spring for the Jisco as well. 

[denjo]

Just my experience that the quality of the transport will determine the extent to which you will hear a difference with the JISCO function; the higher the quality of the transport, the less likely JISCO will make much difference, vice versa. I have also observed that the quality of the digital cable (RCA) does not make much difference, probably due to the JISCO function (?) Other than a Bleden cable, I have not tried any other power cable that feeds the Altmann and cannot say whether the quality of the power cord will make much difference. Any experiences from other Altmann owners on the effect of power cords feeding the DAC?

[tanchiro58]

So with the JISCO on did it make a big improvement?

In my system when I tried to switch the Jisco I can hear a slight improvement in resolution but big improvement I did not notice any. Again my transport is SB2 (modified with Newava pulse transformer) powered by CI VDC-SB PS. Besides there is nothing fancy.

[JP78]

theoretically speaking, a 16bit dac only part cannot resolve 16bits of data due to the inherent loss of receiver due to jitter transfer function.  according to the receiver chip, this is 93 1/ps approximate of jitter loss, resulting of 1-2 bits of data loss.  of course, most capable engineers will tell you this amount of resolution loss is inherent to the recording quality of the disc, and they are most likely correct.