Hi i think im the only one who have compared a 1000 houers DAVE to a new one with 1 houers break in as i have already posted a couple of pages back, but i do not think so many did read it, because it was not any reaction at all !???!!??
But the result was with my bat hearing not a Single difference at all!!
Totally dead race btw the old DAVE and New DAVE, after a few hours / days of comparing.
So it is our brains of some of us that do the break in, not my brain, but for some.
Yes I would be very surprised if Dave did have any significant break in, but brain break in is very real - to me at least.
But break in can be a major hardware issue. In the 1980's my products did suffer from break in, and in the early 90's my DAC's (PDM or DSD DAC's not pulse array) were very variable.
This can be caused by a number of issues:
1. Distortion varying with temperature. The most obvious way is output stage bias currents drifting with temperature, but there are a host of other effects too.
2. Electrolytic capacitors - these have significant break-in with impedance, linearity, and leakage current varying with time - they often need 90 days on to maximise performance.
3. RF noise - this can vary with time too, and in particular can give the effect of ones system varying in SQ over time. In the early 80's my system only sounded at its best at 2AM with the lights out. Once I understood the problems of RF noise and eliminated the issue then SQ got a lot better and it became consistent - it did not matter what time of day, it sounded at its best.
With DAC's there are a host of issues to contend with, and there is a very strong link with consistency of measured performance and SQ. In the early 90's, the DSD DAC's I was making at the time were a nightmare from a consistency point of view. Each one measured a bit differently, each one sounded slightly different. That's why I got into designing my own DAC technology, as the only way of solving these issues was to take control over every element within a DAC and to apply solutions that would eliminate these issues. So for example - normal chip DAC's have a reference voltage pin that you have to decouple with an electrolytic to get low noise. The reference circuitry is built inside the chip, so you can't solve this issue. But if you use a discrete DAC, you can design your own reference circuitry that innately has insignificant noise, so then you do not need an electrolytic to decouple something that is not really good enough in the first place.
I was actually chatting to Matt (production director Chord) about the issue of Dave having such low THD and noise - and the THD and noise at 2.5v RMS OP was -127.3 dB and -127.5 dB for the two DAC's, and every Dave they measure is exactly the same. Moreover, it does not matter if its cold or hot, old or new, with horrible noisy jittery sources, it always measures the same. And each one sounds the same when it goes through their listening tests.
So yes break in can be a very real problem. But when it happens, it supplies a very real opportunity for the designer - if you can find out what the issue is, then you can work on fundamentally to eliminate it - then you end up with even better sound quality, and no break in or inconsistency too.
Rob
