Digital input amp

I see a few coming on market.  Previous threads were quite old.

They take a USB or other input. No DAC on the front end. Just the DSP engine to do volume, eq, etc, then whatever conversion to PCM to feed the class D output. So the only "DAC" is the output stage.   This makes sense as it further reduces the functions in the chain.  I have not seen objective testing or any reliable subjective testing. The ones I have seen are Infineon processer based. No idea if the output filtering or feedback implementation is up to the Purify quality.   I guess the next innovation is the GaNFET output.  One has a DAC to feed a sub out. Easy as any old $5 DAC will wo there. 

I was browsing and came across the Sajab A30a. ( quite inexpensive)  Peachtree has the old Gan-1 but coax PCM only.  That would be fine if it managed buffering and clocks internally. Unfortunately my all-in-one only has USB out. 

I suspect there is a lot to be learned here but it makes sense to me for the future. 


Whatever okay. I will stick to known engineers, designers and builders that have a stellar product line and reputation as my sources of information. Not an unknown commodity as such.  You also seem to be very attracted to cheap, economical products. Are you a regular from ASR? 

  FYI, I have designed and built SS, tube and amplifiers. I have a degree in electronics.

This technology HAS NO DAC.

@tvrgeek If this is so, then the amplifier is not also class D. Class D is a very specific class of operation. Since you apparently have a degree, then you know that class D was proposed in the 1950s and the first home implementations were sold in the 1960s. You also know the building blocks required. So pick one: if its class D then it has a DAC built into the same box to which the digital signal arrives prior to the class D circuitry and probably one the same board as the class D section.

If this is false then its not a class D amplifier inside although it might employ switching technology.

Thank you Ralph. Much like the Gold Note PA-10 that employs switching technology (their version of GaN) and is not Class D as some of the  audio journalists have misstated over the last couple of years (Darko). 

If this is false then its not a class D amplifier inside although it might employ switching technology.

Of course the OUTPUT stage is an integrator. I said so from the beginning.  Gad how some here want to be so superior.  The entire point is this is a new technology worth watching as it changes the entire string. The Peachtree Gan1 does not have a traditional front end DAC.

I also got some comments from the local dealer who has heard this unit and they suggest it is not quite ready for prime tike. 

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