I have Benchmark DAC1 with updated Op-amps. It works
well with my warm sounding speakers. According to
Benchmark's technical Director John Siau it was purposely
designed not to sound warm, but rather natural. Warm
sounding gear can be wonderful with voice or guitar but
can, in worst case, make percussion instruments (with
complex harmonic structure) like piano to sound out of
tune.
In addition DAC1 has strong jitter suppression making
sound cleaner, than many, including me, got used to.
Initially it sounded so clean that I listened if
instruments in the recording were not missing. Because
of that many call it clinical, sterile sounding suitable
for sound engineers and not for the audiophiles. In the
recording studio test all people agreed that Benchmark
DAC1 sound was the closest to original performance, but
it wasn't their favorite DAC.
First DAC1s sounded little thin because of NE5532 Op-
amps. Around year 2000 Signetics factory burned down.
Texas Instruments bought license and made larger die,
fuller sounding chips. I replaced them with even better
sounding National Semiconductor Op-amps, that newer
Benchmarks use. Also, output impedance on RCA outputs
was too high making it less than perfect in some systems.
Benchmark corrected this (revision).
To me it is a fantastic sounding DAC while, according to
reviews DAC2 supposed to be even better. I use it
without preamp - straight to power amp. There might be
better performing DACs but Benchmark is very good for the
money.
As for Benchmark being Benchmark - sound is a very
personal thing and is also system dependent. Some people
love DAC1, others hate it.