Esoteric K-01

I have asked this same question a while back, owning an Esoteric Rubidium clock and also Apl-modded gear. Once I understood the different functions of a "clock", I see why the external clock, while nice to have, is nowhere near as critical as the internal clock.

I'm not an engineer, but Alex and others have explained to me that the external clock controls the Speed or precision of the clock frequency. The precision of the clock frequency has nothing to do with the jitter introduced to the DACs but with speed ONLY. In other words, if your external clock is at a lower frequency than that specified, the music will play at lower speed and vice versa. So the stability of the external clock has nothing to do with jitter. Alex said his clocking approach reduces jitter to a level that is unobtainable even with an atomic clock, unless it clocks the DAC chips directly which is impossible. Having the internal clock in close proximity to the DACs (a few inches) results in greatly reduced jitter, which is audible as a purer signal output. Consequently, as I discovered, trying to apply external clock measurements to an internal clock totally misses the point, because they are controlling different things. That is also why most good CD mods will always contain an upgraded internal clock.

Hopefully, I didn't just confuse you; an engineer or Alex could probably explain this more clearly, or not :-). The point is, with the NWO-M, my G-Os Rubidium clock becomes totally extraneous for this system.

Based on your explanation, use of an external clock does not reduce jitter in a single box player. It should not improve the sound. It appears, an external clock could increase the noise floor and have an adverse effect on the sound.

Your comment, based on Alex's explanation, indicates that we are being misled by companies like Esoteric and DCS, and reviewers like Robert Harley who claim highly accurate external clocks reduce jitter and improve sound.

I would like to hear from Alex (and anyone else who cares to comment) on these questions/issues).

What are you doing with your G-orb?

While it does not reduce jitter, a good external clock can have some benefit, depending upon how resolving your system is and what the internal clock is doing. I have heard my system sound better with the external clock in it using my UX-1, but that's before the player has the benefit of Alex's clocking. I don't think I'll ever know whether an external clock would improve Alex's internal clocking because I doubt that he'll ever build a piece that would take an external clock.

I'm pretty much out of my league technically to explain this any further - I don't know WHY the external clock made things sound better, it just did. It was most noticed when I turned the external clock off - some of the airiness seemed to be missing. I'm sure Mr. Harley can explain this much better than I.

Matjet,

I tried posting a response but it looks like it was not up to moderator's liking, and probably for a good reason.

Anyway, here is a summary of what I think:

1. Esoteric digital is synchronous so it benefits from external clock for the sake of synchronization between multiple clocks used, even in the single-box players. If you are trying to justify external clock for your K-01, I am sure you will be happy, so go for it.

2. APL Hi-Fi digital is asynchronous so there is no benefit from using external clock, even if it is Atomic.

3. To my knowledge, clock stability has nothing to do with clock jitter. For example a clock rated at 25ppm will result in 0.0025% speed stability. Clock rated at 1ppm will result in 0.0001% speed stability. In both cases, this is something you cannot hear and in both cases the clock jitter performance (short term stability) remains the same.

Best wishes,
Alex Peychev

Hi Alex,

I appreciate your response. However, I am still confused.

If a more accurate external word clock does not reduce jitter, how does it improve sound in a single box CD/SACD player that has only one master internal word clock? Synchronization by an external clock would be unnecessary since there is only one clock. The unit's transport is 'slaved' to the internal clock which connects with the DAC. The transport and the DAC are already synchronized by the single internal word clock.

According to what I have read (at least the way I understand it), it is inaccurate timing and/or timing errors that lead to clock jitter. A more accurate and more stable word clock, provides more accurate timing and fewer timing errors. The result is significantly less jitter resulting in improved sonics.
Is this not an accurate statemnt? Please explain.

Could you explain the difference between asynchronous and synchronous digital in layman terms and tell why you feel asynchronous digital is better than synchronous?

Thanks again