« Reply #33 on: June 06, 2006, 05:07:15 PM »
the UA5 shows significant distortion (eg., 1% THD), when driven above -3 or -6dB. I *believe* this is due to the ADC and not the opamps.
I think the first is a *defect* in the design of the UA5, but I cannot explain why or how to fix it. For comparison, driving something like a Minidisc with the same signal (line in, up to -1dB) does *not* produce the same distortion. This unit it *broken* in my opinion! A cheezy workaround is to run at -6dB always. Never let the clip light turn on and you will get better sound out of it, even if you have to add that 6dB back in post.
- The ADC has got maybe 1% distortion (instead of 0.1% what it should be). It *should* not have this. Probably some setup of the ADC is at fault. It is a defect, but I don't know how to fix it. So, drive at -6dB or so to avoid this.
has anyone contacted doug oade to see if he is aware of this? I'm very intrigued to see what his comments would be.
I don't know Doug, but I'd love to hear his comments. My guess is that noone has systematically tested this. Also, since he isn't working on this unit anymore it doesn't matter. But if anyone knows Doug go ahead and ask his opinion.
This is a prime example of the pitfalls of just "using your ears". You'll never notice unless there are huge waveform patterns like in this thread. Damn, I hate companies that sell broken products!
Richard
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Pre/ADC: Presonus Firepod & Firebox, DMIC20(x2), UA5(poorly-modded, AD8620+AD8512opamps), VX440
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