Are Pre-Amps necessary?

mitch2

Interesting, it has to quote:

"The clever implementation of the volume control by lowering or raising the reference voltage "in the converters" is something I have never seen before and works flawlessly."
" And, its volume control is neither conventional analog nor lossy digital."

This to me means you would definitely have an I/V (current to voltage converter) stage after the R2R dac chip set, and then also an output buffer with or without gain.
It’s output impedance is <100ohms SE at 2v output, which means it has an output buffer, and is a great candidate for direct to amp connection, and no problem with your SMc monos 10kohm input impedance, they only need 1v in, for full peak wattage output

So Mitch, get rid of all those preamps you have

• Hattor Audio Mini Passive-Active Pre with Takman REY, XLR, and opamp active buffer ($1,550)
• Benchmark LA4 ($2,599)
• W4S STP-SE ( $1,999)
• Schiit Freya ($850)
• Tortuga Audio with CuTf caps ($4,019)
• SPL Volume 2 ($499 - considered but ruled out because no remote volume)

Because you "should" blow all of them away, with what you have above, by going direct.

Cheers George

The Russian euro15k Wagner Audio Dream Dac dac also uses this volume system for going to poweramp direct.
https://www.monoandstereo.com/2016/06/wagner-audio-labs-super-r2r-dac.html

Cheers George

Have had Burmester 001, DCS Puccini with clock and now Burmester 089, which all can drive amps without preamp and in every case prefered the sound with preamp (Burmester 011 and Arc Ref 3)

George, not sure where your list of "all those preamps" came from but of those, the Khozmo (i.e., Hattor) is the only one I have owned.  I do own McCormack's TLC-1 passive/buffered stage that Steve has upgraded to a much higher level that he calls  "very close to my VRE-1."  When I owned that Metrum Adagio DAC with internal VC, I modified the TLC by taking the Shallco VC switch out of the circuit (replaced it by soldering two AN Tantalum silver resistors to the board) thus turning it into a unity gain buffer w/o VC.  I did that because, to me, the Metrum DAC sounded noticeably better with the active buffer in the chain, even though the DAC output 4V.
I have since moved to Mojo Audio's EVO B4B 21 DAC, which does not have a VC so I added the passive Khozmo unit, which provides remote VC, balance control, and a nice visual display.  I have tried running my system with just the Khozmo passive unit but I much prefer the sound with the TLC active buffer also in the playback chain.