I've broken the warranty of my RME adi-8 QS and opened it, was curious to look at the op-amps,
after reading on the manual:
"While the analog limiter is constantly within the signal path, it operates
fully transparent as there is no control signal generated".
jrc 4580, at least [not bad..] 2 for each A/D ch and 2 for each D/A ch:
jrc 2043 [part of the analog limiter, I think], 2 for each A/D channel:
So now I have an issue..
why on the hell should I need lot of features, when the analog I/O paths of my converters are probably
worse than all of my analog sources, pres, mics, outboards?
And I dont think that it would applies only to rme adi-8 qs.
What should people do, to have great analog paths in a setup of say 16 A/D D/A chs converters?
Go with radar ada?
Buy a pile of UA 2192?
Ebaying for some old 44-48k converters with great analog components?
Or am I wrong, and the cheap op-amps are doing nothing harmful to the audio signals,
because it matters only the circuitry design?
I've not seen the new model, but the older one used M-Dacs to adjust gain, it was a dirty solution. Those Japanese opamps won't win any awards, they are surface mount so they would need de-soldering for replacement. A set of National LME49722 opamps would be an ideal replacement as they are the cleanest opamps made with THD below -155 db, very quiet (1.9 nv/hz/sq) and precision so they have little input bias current and virtually no output offset voltage.
I´m a bit surprised by the obeservation, that low-quality opamps are said to be used in rme-products and keep thinking of doing a mod to my rme adi8-ds (or at least one to hear the difference).
Mr. Williams, so do you think changing the opamp to a National LME49722 would change the actual sound or more the s/n-ratio in a favorable way?
A quick googling didn´t show me any dealers with national opamps in germany, any alternatives?
This is a new part, not yet into distribution. I bought mine directly from National Semi. These will open up the sound and reduce input noise, but they are still much less noise than the converter chip. They will not recover what is lost in their gain adjustment designs, but still should offer an improvement if you are inclined to do some surface mount re-work.
can anybody tell me why there are analog and digital limiters in certain converters? the lavry converters and the new rme adi 8-qs feature these... whats the point of limiting after the signal is converted to digital? i'm under the impression that limiting during conversion is used only to prevent clipping the a/d converter, pre conversion of course...