Tír Na HiFi

Pics of added Clocks to Rev b Digital Input Board for improved XMOS performance.

Old Board left and new board right:


Close Up

Decided to also post this here rather than the MQN thread:

Pearse, I had a quick look at the pics of the two boards.
First thing to say is that there are substantial component differences between the two boards!!
The two clocks are most definitely audio clocks - one for each speed rate family - surprising these weren't used on the old board as they would be considered the best configuration for clocking. Otherwise, the audio clocks are being derived from one clock sources (the crystal?) by division/multiplication within the XMOS chip & added jitter is the definite result of this.

The question is - are the two clocks being used as a reclocker of the I2S signal on the output from the board (the best configuration) or are the two clocks acting as inputs into the XMOS chip? Probably, only Meitner can answer that?

Hard to know why the Meitner now masks(?) any differences between MQN versions? Is it masking or is it immunity? As Nige says, haven't heard a DAC yet that is immune to upstream differences - this might be a first, who knows?

Have you tried other upstream changes to see if these are audible - changes that, in the past were audible?

BTW, what are the two buttons in the top right pic of the new board - reset switches?

could be because it's not burn't in yet.

sbgk wrote:could be because it's not burn't in yet.

that would be my bet too
detail and airyness yet to come with burn in?
if you think it sounds good now maybe in for a treat

Yea, could be - look forward to how this turns out

jkeny wrote: Have you tried other upstream changes to see if these are audible - changes that, in the past were audible?

BTW, what are the two buttons in the top right pic of the new board - reset switches?

Stopped messing and listening for 2 days John as my head was probably frazzled from all the changes and I was probably in too much of an analytical mode for proper listening.
Will fire up again this weekend and get some more hours on the card before I reach my conclusions, and thanks for all the advice guys.
No idea what the buttons are for John and did not ask as the guys at Meitner and EMM labs are very laid back and it was a piece of work getting all the support needed to get the boards, the firmware and answers to all the questions. I was dealing with 3 different guys by phone and mail who all have their own specialities so I will be in better shape the next time I go asking questions...one of these days I will ask and see....just glad to have it all up and running again!!
Cheers, Pearse.