Transport for DAC

Tbadder - That is true. Good transport makes a difference in general but not with asynchronous upsampling jitter rejecting DACs. I'm using one (Benchmark DAC1) that has very strong jitter suppression with very cheap DVD player (DVD players have good tracking). The only thing affected by transport is jitter and once it is eliminated it won't make any difference as long as player/transport is "bit transparent" (doesn't use any DSP processing or digital volume control etc.)

Mapman - I think that people who prefer NOS DACs (that definitely require good transport) don't object to upsampling but to digital filtering. I enjoy my Benchmark DAC a lot but recently read review of Meridian 808.2 CD player - upsampling player with different type of digital filter. John Atkinson said "it's the finest-sounding CD player I have yet heard". I hope so, for $17k - My Sony DVD player was $60 ($1060 with the Benchmark DAC1).

Al - Benchmark had all sorts of problems so be careful with used one (and the new one has 5 years warranty for original owner). First problem in very early Benchmarks was thin sounding NE5532 made by Signetics (Philips). Fortunately Philips factory burned down around 2001 and license was bought by TI. Die was redesigned (larger) and the sound got fuller. NE5532 is very fine sounding opamp in spite of the price (but horrible DC spects). Second problem was too high impedance on unbalanced outputs (many people preferred to use headphone output for that) and the final minor problem (that my Benchmark suffers) is a little high balanced output impedance. The worst one is at -10dB settings that is perfect with my amp and speakers. I'm forced to use 0dB position (narrower adjustment range).
USB version has different Opamp (but only for the output stage) - newest and greatest LM4562. National got awards for this amp but mostly for combination of great AC and DC spects in one amp. LM4562 is a stronger amp and output divider was redesigned (reduced impedance). Oh there was also something about limitation to 96kHz at optical. It was changed to 192kHz with rev F. (same rev. F reduced unbalanced impedance to 30 Ohm). Benchmark has 30 day free evaluation program.

Word of a warning - Benchmark is not a warm sounding DAC. According to John Siau it was meant to be neutral because warm sound (exaggerated even harmonics) sounds wonderful with voice or guitar but not with instruments that have more complex harmonic structure than simple overtones (like piano or percussion instruments). He even mentioned that piano might sound like out of tune with some very warm systems. I don't have much of experience in audio and therefore believe in what I read.

There are mods for DAC1. One of them is to change cheap amps to OPA627. Benchmark tried them and they prefer NE5532. They even show which harmonics got worse. Steve from Empirical Audio says that microdynamics (low level performance) is improved with OPA627. Steve also improves power supply - filtering and decoupling. In spite of -140dB measured S/N of the stock units Steve says that dynamic performance is improved (pulse response). One thing not acceptable to me in mods is removal of upsampling scheme. I don't question that it sounds fine but requires high quality transport a not my $60 DVD player.

Mapman - I don't know DAC like that since I wasn't looking, but heard that people had good results with tube preamps. My Benchmark serves as a preamp.

According to Stereophile Bel Canto is a little better (not necessarily warmer) than Benchmark but for 2.5 times more money.

Al - are you running XLR or RCA?

Shadorne - Thank you - that's probably the case especially with my amp (class D). 0dB setting is OK - it gives full power at about 1 o'clock position of the volume knob. The problem comes when I listen very soft at night. Fortunately volume pot on my Benchmark works from zero with very good tracking - might be coincidence since it doesn't look expensive.

Al - One review of the Benchamark claims way better performance at 0dB settings for XLR (four jumpers inside) than any other position (-10, -20, -30). I can hear a little livelier sound at 0dB than -20dB but -10dB is much worse and my 0.5m cable has total of only 6pF/ft x 1.5ft=9pF.

Benchmark stated in manual that for XLR:

Setting (dB), Output impedance (ohm)
0 60
10 1600
20 500
30 160

and -10dB is really bad. If you're concern with it - get DAC1 USB. I think that pre has also LM4562 on the output and different divider but verify. I'm not sure how better it is - will check their website for the manual.

Shadorne -

"To me the greater the precision the more problems/anomalies you discover in your recording collection."

This is very true. I discovered big difference in recording quality with the Benchmark. I like its clarity but it took a while to get used to it. At first I had impression that something (some instruments?) must be missing. I even heard opinion that "sound blob" performance is more musical than "analytic" Benchmark's performance where you can distinguish individual instruments. Some like also a little THD to make sound "lively".

I hear people saying that all is subjective and if you like it it's better for you. It took me a while to really like Benchmark and I'm always ready (with my limited experience) to learn to listen.

Shadorne - I'm using XLR cable without adapters. The only gain adjustment with XLR is either 4 jumper settings or volume knob on the front (if you chose this mode).
I'm using volume control (no preamp).

My power amp (Rowland 102) has only XLR inputs rated as 40k impedance. 9pF with 1600 ohms of output impedance makes fc=11MHz. It has to be something else.

I would thing that I might compare different levels or "hearing things" but review I read claims the same and Benchmark lowered this output impedance with stronger output drivers and lower dividers in DAC1 USB. I will try to find link to this review.

Shadorne - I'm perhaps very lucky with this particular unit. I used more expensive and larger ALPS "Blue Velvet" pot with conductive plastic track and matching was worse than this tiny pot (Alpha I think).