Van Alstine Omegastar?

[Brandon B]

Anyone with an opinion on these? Review of one over at HTT and they seem pretty pleased.

http://www.avahifi.com/root/equipment/amplifier/omegastar_amps.htm

BB

[JonMarsh]

I first met Frank Van Alstine in about 1976, if I remember correctly. I was a partner in an audio salon, and I'd just recently been doing some experiments with a highly modified Dyna ST400- actually, it was taking the guts of the 400 (power transformer, heatsink assembly, etc., and building it into a new chasis with 100K uF of filter capacitance (versus 20K in stock amp), 220 uF of polypropylene bypass capacitors, (none in stock amp), and double the number of output devices. Frank was also into doing mods for Dyna gear, and he had a pretty interesting sounding preamp, which we decided to carry, though the cosmetics were nothing to write home about, considering the price.

He's been going what he's doing now for quite a few years, and has built up a loyal following in publications like the "Sensible Sound".

The verbage describing the design of the new OmegaStar series is a bit obtuse by engineering standards; it's designed to sound technical without really describing anything in the detailed terms used by the engineering community.

The OmegaStar amplifiers have no overall feedback, so the input circuits simply cannot overload on an overall loop error correction signal that doesn’t exist. Feedback does exist, however, as a unique active and buffered powered feedback loop matched perfectly (electrically and thermally) to the active buffered input parameters. The amplifiers are perfectly balanced top-to-bottom and also balanced in input and feedback drive parameters.

This description would lead me to believe that he is using nested local feedback loops, with no overall loop feedback input to output. This is a bit like some of the Denon monoblocks, like my POA4400's and POA6600's, which use a feedback loop around the input and voltage gain stage, and a DC servo around the power stage, but no overall loop feedback. This is a step in the right direction, and is easier to do than a gain stage topology which uses no loop (local or otherwise) feedback, such as the Ayre amps and preamps or my DAC.

Frank does have a good ear, and listens closely to what he builds (as opposed to gazing lovingly at the THD meter so I would expect these to be another clear sonic step up over his Omega series. The new "OmegaStar DAC" has also won a Golden Ear award at TAS for 2002 as one of the best of the year products.

Best regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Brandon B]

Thanks Jon.

You are truly a one stop shop for history, background and assessment of audio gear.

BB