Looking for Better Jitter Reduction in a DAC

So:
1 problem also exists with other speakers
2 problem disappears using sources with lower output levels
3 already powerful signal with VC at 8 or 9 o’clock
4 problem disappears when pre amp is out of the chain.

4 has the greatest practical importance. For those who want to know the cause of the problem, I think it is now almost certain that the input of the pre amplifier was clipping because the input sensitivity was too high/ the source too hot. If this analysis is indeed correct, and if you want to keep your pre amplifier in the chain, all you need to do is replace the 6 dB pad with a 12 or even 18 dB pad.
You may wel have stumbled on what I think was the reason digital had/has a bad reputation. It was not the quality of the signal, but the gain mismatch between the players’ output and the amplifiers that people were using. Are you happy with the sound you are using now?
I am not quite sure what your current gear does or does not do, but an outboard volume control (passive amplifier by an inappropriate name) could be useful, and if not for you maybe for others. Here is one: http://www.tcelectronic.com/level-pilot/

The Harbeth article is a good one for beginner audiophiles. Thx Willem.

Frankly, if an audio enthusiast has never considered the points raised by Alan Shaw of Harbeth, then they are waisting their money by pursuing a high-fidelity hobby without any understanding of how anything works.

This is like flying without a pilot’s license only not as hazardous. This is like scuba diving or sky diving without taking necessary training and becoming certified. These are the type of uninformed audiophile enthusiasts (and there are soooo many) that are easy prey to the "you obviously need another high $$$$ cable" salesmen.

Hi Shadorne,
That is absolutely right, but the sad thing is that there are many consumer audio products that suffer from this issue. You use pro audio grade gear, and there gain matching is taken very seriously - and quite rightly so. In the old days designers like Peter Walker vary carefully tried to find the sweet spot between too much gain with clipping as a result, and too little, but excessive noise as a result.
Let's indeed hope that this did solve the problem, and that the OP can stop worrying about all kinds of imaginary issues.

@willemj    


This is why I always say,"If changing a piece of wire cable makes a big audible difference then your system problems run much deeper than mere cabling and it is critical to investigate further"

@willemj , maybe I wasn’t clear about #4. The problem still exists when the preamp is out of the system (DAC direct to amp input). When using the amp gain control, music is very loud at about 11 or 12 o’clock on the dial, about 80 dB at listening position. Before I purchased this amp, I checked with Ralph (atmasphere) who believed preamp and amp were a good match. 100 kOhms input impedance with variable gain.

With preamp inline, I leave the amp gain pot at about 3 o'clock.