ro7939

A state of the art preamp w/analog volume control allows users to swap DACs without consideration for the DAC's output current capacity, without consideration for the existence of nor quality of digital volume within or in front of the DAC, and without consideration for any existing or potential sum total input impedance of the load amplifier(s), which might include sub amps with very low input impedance (the norm for such amps). A state of the art analog preamp is positively always required for maximum system flexibility, not a luxury nor performance impediment. This is always true, even while certain users assemble one particular system with fixed, hand picked DAC and amp that may perform best without a preamp, especially a lesser preamp. For any poster here who prefers his DAC direct without a preamp: What is the input impedance of your total amplifier load? What is your DAC's output impedance? (The higher the ratio the better is audio performance, a low ratio is considered 10-1.) Do you maintain DAC direct would outperform a state of the art preamp even if the load impedance was 8k ohm? (Sum total of my sub amps and main amps.) DAC direct always and only minimizes choices, period. The fact that certain users prefer this option does not make this statement false.

My understanding is that all digital VC is of the bitstream variety only. There is no such thing as a digital volume in DSD format, hence the only potential VC for such application is of the analog type. Another way to say this is that the exclusive use of a digital VC disallows DSD file playback. I find it curious that this has apparently been ignored up to now in this conversation, but I apologize if I missed it. There also appears to be a wide range of debate as to what is an "adequate" ratio of output impedance to input impedance; hence what person A may call a "robust" source for a given load someone else would call "fail." I've heard 10-1 ratio is appropriate (less is not), but for others the ratio is much higher (I fall into the latter group). I searched long and heard for preamps in the past couple weeks, and the only preamp vendor I found that specifies minimum load impedance was deHavilland (kudos to them; I bought the Kinki Studio EX-P7 Goldmund Edition SS preamp). I suspect someone making absolute statements to answer the OP is akin to person A stating a concrete minimum amplifier power suitable for person B. There are too many variables. People hear differently. Two persons can hear the same thing and describe the differences similarly, and make mutually exclusive value judgements. There are just so many variables including the length and type of IC cables, and the fact that changing the amp (load) can change the input/output ratios and hence the performance product. I prefer to use among the best music playback software (HQ Player) and hardware dedicated only for music playback (NUC) > low-moderate cost DAC with fixed full level analog output > power amps (which in my case includes two kilowatt sub amps each w/12k input impedance; the total load may drop below 9k ohm depending on the main amp). This allows easy swapping of DAC and power amp, with the preamp taking care of input/output impedance matching under any and all condition. I'm currently pretty darn happy with the "lowly" $400 Pro-Ject Pre Box S2 DAC in the above system. My personal experience strongly contradicts the above stated math touting the performance advantage of digital VC (beyond the fact that there's no such thing as DSD VC): A: $10k Bricasti M1 SE DAC, digital variable volume @ -12 dB > power amp 50k input Z B: $10k Bricasti M1 SE DAC, fixed 0 dB gain > Pioneer VSX-D01 Elite TXH receiver pure analog inputs -12 dB (don't laugh, the analog stage is good) > same power amp as above B thoroughly outperformed A by big margin, throughout, no exceptions. I went back and forth at least 3x. BTW, Re. the performance level of the M1 DAC: I have a decent quality SACD player. I did this AB test. The music program in both cases was a well recorded Alison Kraus Live, dual layer SACD/Red Book: A: SACD player analog output > preamp B: Same SACD player playing the same disc, but this time the Red Book layer, coax digital output > Bricasti M1 > preamp (VC lower for same SPL, SACD level is attenuated vs. Red Book). B totally incinerated A, almost sounded like a different performance, a shocking improvement. I state this to show the M1's performance level relative to the earlier described AB test. Yes, as someone stated, one can err Re. an analog VC. The difference is that with many preamps, a visual glance can confirm the volume setting, whereas in the digital realm some invisible software setting can be off, and take a lot longer to find and fix than a glance across the room.

So says someone who never heard of an impedance mismatch.

For powering the Sonore uR: has anyone compared a battery to suitable Hypex SMPS? The latter are renown for being among the world's best and quietest. I intend to check which Hypex SMPS is best suited for this application.