Class D Technology

I'm not sure what this "class A input stage" is.  Input stages are almost always class A (would be stupid not to)

+1
I've never seen anything but Class-A input stages, it BS advertising to con the gulible.

Cheers George

Kijanki - Yes I meant voicing as a coloration to differentiate a boutique amp from a stock Ice Module. Some feel that adding a custom input stage and not using the stock power supply creates a superior sound to their ears...which I can't argue with. 

mapman14,180 posts01-03-2017 2:58pmI do not have "ice modules" . i have stated repeatedly I have BelCanto Ref1000m amps. These use ice modules but also custom input and power circuitry and the price and sound reflects that accordingly.

Again generalizing and glazing over facts and details to help an argument helps nobody and is a disservice.

I would likely not have been satisfied using that older revision of vanilla Ice modules to drive my speakers which is why I opted for a better design. The original Bel Canto ref1000 was vanilla icepower (and much cheaper) and the differences between the two are well documented.

  

Yes, sometimes there is additional circuitry to Icepower modules.  For instance my small Rowland has additional instrumentation amp (THAT1200), that improves common mode noise rejection as well as increases standard 10k input impedance to 40k.  Box is pretty indeed, but since it is solid billet aluminum chassis - board inside is acoustic resonance free.  There is a purpose to that - but when manufacturer puts Mosfet stage in a plastic blue box, calls it fancy name "Analog Cell", describes it as class A with no feedback and inserts picture of the board with this blue module in their literature - then it makes me very suspicious.  Not only that using "class A" is to pray on non-technical people, but also second statement is not true.  There is practically no stage without feedback.  Even resistor in the emitter (or source) of transistor is a form of the negative feedback.  First stage might be outside of the global negative feedback, but calling it "no feedback" is again praying on the common believe that "no feedback" is a good thing.
Because of all that I'm very suspicious about additional Mosfet stage used for the "voicing".   We also have to assume, that B&O engineers, that are fanatic about sound, and Jeff Rowland neglected to properly  "voice" it.  Would people buy this amp, after finding in the sales literature, that the company just packaged inside standard inexpensive Icepower modules?  Most likely not and that's whole reason for the "puffing".

http://www.psaudio.com/stellar-m700-mono-amplifier/

The useful purpose of a custom input stage on most Icepower amps is to raise the input impedance  (10K to start with on older versions at least) to enable good performance with higher output impedance tube pre-amplifiers. Its a performance/integration enhancement not just there for "coloration". If pre-amp is lower output impedance SS there is no benefit at least on paper.

Benefits of improved power supply in any amplifier should be obvious.

The PS Audio amps are being built as a lower cost alternative to their higher priced fare.