has anyone tried PS Audio perfect wave duo

I don't get it.... This unit has a one disc memory and plays the disc from memory, not directly from the disc.
In effect, this is a one disc music server.
Am I missing something or is this just the ultimate in audiophile marketing hype?

I don't think you are missing anything. Any lo-fi cd player, and I believe any $20 computer cd-rom drive, not to mention any audiophile-caliber digital transport, has a solid state buffer memory (aka cache) through which the data coming off the disk is passed, before being clocked out at a fixed rate which is not subject to the (very large) variations in the rate at which data is retrieved from the disk.

The only relevant difference that I can glean from PS Audio's literature is that their memory is 64mB, which is much larger than typical. But I fail to see how the larger memory size would convey any benefit, assuming that the disk-reading mechanisms are performing in a half-way reasonable manner. The 64mB, by the way, is nowhere near large enough to cache an entire disk (which may be up to 700mB or so). PS Audio's writeup describes it as being able to store "up to 3 minutes of music," which is in the right ballpark.

I have no doubt that it is a very well engineered and good performing player, but its descriptive literature is misleading and disappointing at best.

Regards,
-- Al

Almarg,

The larger cache may be needed to handle the higher res formats that this device is advertised to handle.

I think that would be the main purpose.

I can see this as an effective though pricey out of the box solution for those seeking the bleeding edge of current digital formats.

Personally I will stick to the music server approach but I can understand if many are not comfortable mixing computers with their audio on their own.

Hi Mapman -- My main point was that it is misleading to claim that other transports output data directly from the optical read mechanism, and that other transports are therefore subject to the timing variations which inevitably occur as data is read from the disk which is spinning at a varying, motor-controlled rate.

But re the larger cache, all that is necessary is to have a cache which is large enough to not become emptied under conditions of worst case variation of the rate at which data is read from the disk. A few seconds worth of cache should be way more than enough to accomplish that for any audio format, for any reasonably well performing read mechanism.

Best regards,
-- Al

AL,

Yes, it would make little sense to output time sensitive data directly from an optical read device. I've always assumed that most or all devices do not do this but was not sure.

Usually if a cache is not big enough, a clear audible dropout will occur I believe and not a subtle change in sound.

I would expect the same to occur but much more frequently if bits were read direct from a relatively slow and more error prone optical device and that seldom seems to occur with most properly operating readers.

Does that sound right?

Hi Mapman,

Yes, if the cache were not large enough to support the timing variations of the read mechanism, clear audible dropouts would occur.

If the optically-read data were conveyed to a dac, or to the internal dac of a cdp (transport plus dac in one unit) without any memory cache in between, I would expect the result to be a total mess combining dropouts with various distortions associated with the timing variations.

Best regards,
-- Al