Jitter reduction, best device?

Asi_tek - Upscaling, also called asynchronous resampling is not bandaiding. It is instead (and not on the top) of traditional extraction of data.

In typical CD-player, as far as I know, stream of data coming from the laser has jitter and varying frequency. Phase Lock Loop is used to sync DAC converter clock to average frequency of the data stream. I believe that now they use double PLL to improve response and FIFO buffers to provide more stable DAC clock.

Upscaling reclocks data with asynchronous clock of much higher frequency. Benchmark DAC1 does manipulation of data equivalent to 1 million times oversampling making DAC clock accurate to 5ps. DAC1 also has PLL but very crude and fast - just to get input data.

Typical CD player has some analog circuitry that mutes the output in between tracks or during invalid data. This circuitry is audible according to some users who tried to disable it. Benchmark detects valid signal and does muting in digital transmitter chip.

bottom line: the only way to tell if a jitter device will do something in your system is to try it. everybody could guess all day long about things. but in the end, you won't know if it works or not for you until you test it. also, all the room tuning devices, ac filters, 20 or 30 amp dedicated wiring, room lens, different speaker positioning, claws, beaks, better cables, better power cables, etc... i don't think you can say that none of these will not have an impact in your system until you try them.

Rbstehno is right.

Like most gadgets, all that really matters is if you hear a difference for the better thats worth it to you.

If it works, who cares how it did it?

Mapman

"If it works, who cares how it did it?"

That's true - but understanding helps to narrow search. Sounds of upsampling, oversampling and non-oversampling DACs are different. Many people don't like sound of upsampling converters (Muralman - are you there?) while I praise clarity and transparency of Benchmark DAC1 and would look for similar one in future. Understanding what jitter is and how to prevent it helps as well.

There is nothing wrong in understanding!

There is a renewed interest in jitter because of the new PC-based servers. The data from a hard drive is read in blocks without an inherent clock. An SPDIF clock is generated at the same time that the SPDIF data is created. It's this clock that has the troublesome jitter. Most PC manufacturers and even sound card manufacturers don't care that much about jitter. It's only a few audiophile nuts like us who are concerned about it.

I'd like to see SPDIF jitter measurements standardized and published for PC's and PC soundcards that output SPDIF signals. Then we could really tell how bad the jitter was and whether we need outboard jitter reduction. (The SPDIF signal is what goes between the PC and the DAC, either in optical or coax cable)