Preamplifier power supply

Casouza, thx for your precious input. It leads certainly to a greater understanding of this matter. Why do some digital front end manufacturers like Wadia advocate the use of passive (digital) built in preamplifier? If transformer based preamplifier is the answer, why are most preamplifiers still built in the conventional way?

Chris

What do you think of the so called passive preamp with buffer?

Chris

I'm wondering myself, like the Pass First Watt B-1.

Chris, my comments were regarding resistive passive preamps versus transformer passive preamps. Between those, I prefer TVCs.

Most preamplifiers are built the traditional way because people need gain, specially audiophiles with phono front ends, low gain amps and low efficiency speakers. A preamp must be (ideally) able to cope with all kinds of sources, amps and speakers, no easy task.

As for Wadia's integrated preamp, it is active, not passive (I have seen the opamps inside a Wadia). Its attenuation is partly analog, partly digital. It sounds great and it replaces handsomely a preamp + PC + IC, as long as one adjusts the internal analog gain DIP switches in order to use a MINIMUM of digital attenuation. If one goes deep into digital attenuation, there is a clear loss of resolution/detail/soundstaging.
As for active preamps, there are excellent ones, some with gain, some with unity-gain buffers. I am not familiar with the Pass buffered preamp.

In summary, there is no clear-cut BEST solution.

In general, I follow these rules-of-thumb:

-If your system lacks dynamics and punch or you need to use the preamp above 3 in the dial, you need more gain, therefore no passive preamp will do the trick. Buy an active preamp that drives your system to VERY LOUD levels and still has about 6 db spare gain for those quiet recordings.

-If your system has too much gain ( volume pot stays around 8 in the dial, "jumpy" volume control near 9) or you can hear noise/tube hiss, you need a preamp with less gain or a TVC preamp IMHO.

-If you want a minimalist solution, a Wadia or Audio Aero CD player connected directly to the power amp will sound great IME.
Audio Aero has an internal active analog, tube-based preamp followed by a buffer to lower output impedance.
Opus 21 also has an internal solid state active analog preamp (SS) and it sounds great for the money.
There may be other brands of CDPs with internal preamps.

Anyway, my original point about the cap-charging current peaks in a preamp DC power supply reaching 10 times the average current remains (and is validated by engineering textbooks). A transformer that is specified for 10 times the preamp continuous power draw is NOt overkill, it is just sensible design.

I hope this helps

I can think of hundreds of scenarios where an active linestage is necessary (as I can think of just as many scenarios were SETs will sound terrible). But the question remains, if you have plenty of gain, low capacitance cables, 100kohm input impedance on the amps with high sensitity - that is a source and amp/speaker combo where there absolutely no need for gain or buffering to match impedances, under though circumstaces how and it what way could an active linestage better a passive resistor preamp? I have had a CAT, Lamm, ARC, Joule ME, Dodd, and even a Bent TAP and now I use a Lighspeed Attenuator to drive the Music Reference RM10 and RM9 SE amps - I don't hear loss of dynamics, soundstage, texture, PRAT, bass, or anything else, except noise. Though I do use a Atma combo becuase the the passive approach just does not work for me with my Atma amps. I would not draw conclusions about passive preamps unless they are in the right system context, as I would not judge whether 1.5 watt SETs are any good by trying them on a pair of Thiel or B&Ws. And if I needed buffering, I'm sure the TVCs or AVCs would sound better than the resistor-based passives. Now this may all work becuase the power supplies in the EMM Labs gear is pretty beefy.