DAC-Preamp having these specifications?

The Manhattan II’s price of $6k knocks this out of contention. The $2200 Brooklyn DAC+ includes one less analog input than I would prefer, but has the desired output impedance (75 Ohms). Not sure what their mix of op-amps in the unit might be. 

The Benchmark DAC3 is another contender that appears to fit most of the specifications list. I understand that some ding it for having too many op-amps in the unit that adversely affects its sound qualities compared with units having discrete components. Audioengr told me the op-amps contribute to the unit’s internal jitter in the DAC section being too high.

@shadorne yes, I reviewed JA’s measurements of the DAC3 this morning to see whether he measured the jitter. I know it’s low. 

DAC technology is a moving target. The ESS Pro chip set in the Benchmark product is already obsolete, though I’m sure it’s great as implemented.

http://www.esstech.com/index.php/en/products/sabre-digital-analog-converters/audiophile-dacs/sabre-p...

Though it’s not a stated product specification, it would be desirable to have some commitment to upgradable pathways for the product.

@1graber2 the BC 3.7 checks all the boxes except price. It seems $2k higher than what I’m interested in spending. 

Just for grins, I pulled out of storage my CAL Delta transport, Sonic Frontiers Ultra Jitterbug (reclocks transport signal to <40ps jitter) and Theta DS Pro Basic IIIA (interlinked via Canare AES/EBU 110-Ohm digital IC’s) and ran it head to head against my Oppo BDP-83SE as a Redbook system (16-bit, 44kHz). The Theta has Analog Devices processors, akin to the Schiit Yggy (Mike Moffat apparently loves implementing AD processors with robust software). All I can say is that the 1996 setup didn’t embarrass itself against a 2010 Oppo player.

@georgehifi If a DAC-preamp manufacturer uses only an analog volume pot, then can one assume the digital domain is set for 100% output, thereby ensuring no bit-stripping arises? I’m thinking here of the Benchmark DAC3. 

@georgehifi I thought I deleted my errant post regarding my misread of your suggested “1000-Ohms”. I read your post again and realized you wrote “100Ohms” rather than “1000Ohms”. My bad.

The ATC (analog) preamps have a rated output impedance of 10-Ohms. But I don’t have one of those, opting instead to explore a DAC-preamp. 

Thanks for your advice. 

@georgehifi I looked at the owners manual after posting. I think you are correct about the digital domain volume control. Here is what their manual says:

“HGC is Benchmark's unique Hybrid Gain Control system. The DAC3 combines active analog gain control, passive low-impedance attenuators, a 32-bit digital gain control, and a servo-driven volume control.

“All inputs are controlled by the rotary volume control. This volume control moves in response to commands from the remote control. Analog inputs are never converted to digital, and digital inputs never pass through an analog potentiometer. Digital inputs are precisely controlled in the 32-bit DSP system. The DSP system preserves precise L/R balance, and precise stereo imaging, while avoiding any source of noise and distortion.

“Benchmark's unique passive output attenuators provide distortion-free gain reduction without reducing the dynamic range of the converter. The attenuators optimize the gain staging between the DAC3 and the power amplifier. This optimization is absolutely essential for maximizing the dynamic range of the entire playback system.”

The output impedance isn’t uniform as a function of the different passive attenuator pads:
Attenuator:      Output Impedance
0 dB                      60 Ohm
-10 dB                 425 Ohm
-20 dB                 135 Ohm

The owners manual of the all digital input version, DAC3 DX, makes even more clear the digital volume control of the outputs:

”The MAIN bus drives the XLR outputs and one pair of RCA outputs. The MAIN bus delivers the highest performance because it uses three conversion channels wired in parallel for each XLR connector. The main bus uses 6 of the 8 channels in the ES9028PRO D/A conversion chip. The remaining two channels in the ES9028PRO drive the AUX bus.“

@audioengr So the DAC3 uses method 2, with the attenuation arising after the last active stage? I’m unclear about this. 

I have sent a request to benchmark about this topic.

@shadorne thanks for the links. Looks like the DAC3 HDR-VC™ system combines an active gain circuit with a low-impedance passive attenuator, where the motorized volume pot controls the active gain circuit and the passive attenuator is located after the active circuitry.

@shadorne yes, I see that. Rory of Benchmark sent a bunch of links of application notes to me. Looks like they’ve also improved the master clock and how jitter is controlled in the DAC of the DAC3 unit.