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Benchmark DAC1 now available with USB
Jun 17, 2009 at 5:37 PM Post #2,596 of 3,058
Quote:

Originally Posted by gevorg /img/forum/go_quote.gif
Hi Elias,

What do you think about NOS (non-oversampling) DACs? Particularly, ones that use Philips TDA1543 chip in an array of 8 or so, feeded by I2S stream from some re-clocking TCXO (crystal oscillator).


A non-oversampling DAC is basically a DAC with analog anti-aliasing filters. These analog filters suffer from high-frequency distortion and phase distortion. They aren't steep enough to block frequencies higher then Nyquist and leave the pass-band in tact. If the steepness is increased, major phase and distortion issues come about.

Also, since these filters are built using analog components on a wafer, they are severely temperature unstable. They will drift depending on the operating scenario.

Quote:

Originally Posted by gevorg /img/forum/go_quote.gif
A common perception by users who like NOS DACs is that this way the sound is "more musical" and "less fatiguing". Can oversampling DACs like DAC1 sound like this too?

Thank you!!


I can't comment on the subjective impressions of these people, but I find the DAC1 far from fatiguing. In fact, I listen to it all day, everyday. I listen at work here at Benchmark, then I go home and work in my studio while listening through it.

However, subjective impressions are impossible to quantify, so you'll have to listen for yourself to determine the answers to your questions.

All the best,
Elias
 
Jun 17, 2009 at 10:44 PM Post #2,597 of 3,058
Quote:

Originally Posted by G-U-E-S-T /img/forum/go_quote.gif
...please, what specifically is responsible for this crackling sound in a worn volume pot, and what is the particular difference in the new pot that makes it less susceptible to the issue over time? That is, do these volume pots use "brushes" (or some other culprit component) internally, and what is the specific mechanical difference between the old/new pots with respect to such a specific component, that should make the new pot better in this respect?

Thanks again in advance, as always!
normal_smile .gif




Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif
...I will aggregate this information for you and post it a.s.a.p. ...


Hi Elias, just following up with you regarding the above. Hope you are doing well!
normal_smile .gif


P.S. I concur with Elias, the DAC1 is definitely not fatiguing in any way.
 
Jun 24, 2009 at 5:48 AM Post #2,599 of 3,058
I been running my Benchmark Dac1 Pre since a week after Can Jam ended. I think its the best piece of gear I have bought. I just need to find some better recordings to put this thing through. It brought back life to my HD600's and its nice to finally have a volume knob on my Dynaudio BM5A + BM9S setup.

In comparison to my Moodlab Dice this thing whoops its butt on the mid and high separation in the vocals. I been sampling 'Endless Love' duet by Mariah Carey and Luther Vandross and you can tell that there is a major improvement in the detail inflections of the voices.

Only thing I noticed is that the unit is kinda warm.
 
Jun 27, 2009 at 1:39 AM Post #2,601 of 3,058
I don't know how to do a screen capture, so:

Playback settings:

Volume Control on MAX
Replay gain,
source mode none
Processing none

Preamp, with RG info +/-0db(89 db), without +/- 0db. Both sliders are in the mid position, but both source and processing of replay gain is set to none anyway.

DSP manager has NO active DSPs configured.

Output Device is set to Benchmark
output format is 24 bits. Dithering is NOT checked.

Tools/convertor FLAC settings are <N/A> for avg bit rate and level 5 for settings. Preferred bit depth is 16, but the Keep lossless source at original bit depth is checked. Dither is set to never. (I don't use this convertor anyway.)

I hope that's enough info.

The windows volume control is at max, all advanced controls are disabled.
 
Jun 27, 2009 at 12:37 PM Post #2,603 of 3,058
I think I may have fixed the problem

There was some sort of program installed called "SoundMAX". After I uninstalled it, the sound quality seemed to improve. Hopefully it's not a placebo effect.

Initial impressions are that he bass response is not quite as deep, but the difference is very subtle. In some ways, the USB sounds better: Bigger, and better inner detail. The CD may have a slight edge in ambient information, but it's hard to say.

Last night was extremely humid, so I can't say if the humidity levelled the playing field or not. I'll know more after a few days.
 
Jun 29, 2009 at 2:42 PM Post #2,604 of 3,058
Quote:

Originally Posted by G-U-E-S-T /img/forum/go_quote.gif
Quote:
Originally Posted by G-U-E-S-T
...please, what specifically is responsible for this crackling sound in a worn volume pot, and what is the particular difference in the new pot that makes it less susceptible to the issue over time? That is, do these volume pots use "brushes" (or some other culprit component) internally, and what is the specific mechanical difference between the old/new pots with respect to such a specific component, that should make the new pot better in this respect?

Hi Elias, just following up with you regarding the above. Hope you are doing well!
normal_smile .gif


Thanks again in advance, as always!


P.S. I concur with Elias, the DAC1 is definitely not fatiguing in any way.


Hello G-U-E-S-T,

I'm sorry it has taken so long to respond to you.

The pots in the DAC1/USB/PRE are great pots, but the new Alps pots in the DAC1 HDR are simply better. The pots in the DAC1/USB/PRE became noisy for two reasons. The first wasn't the fault of the pot; it was a result of a subtle DC offset in the gain circuit. That was corrected with a circuit revision in 2004. The other reason for the crackle-y volume control was because of leaky pot shafts. Lubrication would leak onto the resistive element. This didn't affect the tone/performance of the DAC1, but it did cause the noise when the volume-control is adjusted. Otherwise, it is a benign defect. We have replaced most of these pots already.

The new Alps pot in the DAC1 HDR has a larger resistive element and wiper element, and a better build-construction, generally speaking. They are more expensive, but part of what you're paying for is increased quality control. They are solid, well-built pots. The larger elements decrease variances, making for more consistent performance. Also, the larger elements are less susceptible to heat (expansion and contraction), also contributing to more consistent performance.

I hope that answers your question. Please let me know if you'd like me to clarify anything...

All the best,
Elias
 
Jun 29, 2009 at 3:08 PM Post #2,605 of 3,058
Quote:

Originally Posted by minidiscs /img/forum/go_quote.gif
I been running my Benchmark Dac1 Pre since a week after Can Jam ended. I think its the best piece of gear I have bought. I just need to find some better recordings to put this thing through. It brought back life to my HD600's and its nice to finally have a volume knob on my Dynaudio BM5A + BM9S setup.

In comparison to my Moodlab Dice this thing whoops its butt on the mid and high separation in the vocals. I been sampling 'Endless Love' duet by Mariah Carey and Luther Vandross and you can tell that there is a major improvement in the detail inflections of the voices.

Only thing I noticed is that the unit is kinda warm.


Hey minidiscs,

I'm glad to hear you're enjoying the DAC1 PRE!

The DAC1 PRE gets warm because it's circuits are low-impedance. This acheives optimal performance, but draws more current then high-impedance circuitry.

All the best!
-Elias
 
Jun 29, 2009 at 3:09 PM Post #2,606 of 3,058
Quote:

Originally Posted by ert /img/forum/go_quote.gif
Elias,

Is there any problem with connecting both the RCA and balanced outputs to two different amplifiers simultaneously?


No problems at all! That is, it won't hurt the DAC1 or comprimise its performance. However, you should understand that the output levels will be different.

All the best,
Elias
 
Jun 29, 2009 at 3:18 PM Post #2,607 of 3,058
Quote:

Originally Posted by Laptopboy /img/forum/go_quote.gif
I think I may have fixed the problem

There was some sort of program installed called "SoundMAX". After I uninstalled it, the sound quality seemed to improve. Hopefully it's not a placebo effect.

Initial impressions are that he bass response is not quite as deep, but the difference is very subtle. In some ways, the USB sounds better: Bigger, and better inner detail. The CD may have a slight edge in ambient information, but it's hard to say.

Last night was extremely humid, so I can't say if the humidity levelled the playing field or not. I'll know more after a few days.


This doesn't surprise me... Equipment companies will throw their DSP plug-in's in-line without your awareness to make their speakers sound better. Unfortunately, these DSP plug-in's are the last thing you'd want for a true high-resolution system.

Keep in touch...let me know if everything continues to work well.

All the best,
Elias
 
Jun 30, 2009 at 5:29 AM Post #2,609 of 3,058
Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif
No problems at all! That is, it won't hurt the DAC1 or comprimise its performance. However, you should understand that the output levels will be different.

All the best,
Elias


That's fantastic. Thanks.
 
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