Old thread, I know.
Just recently I bought a Lite DAC AH very cheap just for fun. Alwyas wanted to try a NOS dac and this was the right opportunity.
After googling a little about the DAC it seems that it is a very inconsistnet piece of equipment. I have seen maybe 5 different types of opamps being used as well as capacitors, resistors, psu voltage etc. It seems that they trow in whatever was on sale at time of manufacturing.
Mine came with OPA627 (or a rippofF, who can tell), with standard metal film resistors, mkt caps, cheap elecrolytic output caps.
This thing was distorting like crazy at low frequencies, quite unbearable. But, it had good dynamics and "life" even with the compression effect of the thing clipping in. So I changed the output resistors from 270 to 150 ohm as recommended everywhere. This was no good, all the "life" was rubbed out of it, dynamics just average and everything sounded too polite, thin, weightless, completely boring sound.
So I changed the resistor several times and in the end settled on 225 Ohm (150ohm with 75 ohm in series) and this was the best compromis. No distortion and still a good portion of that life like sound. Still not perfect though so I tried the passive od, direct out via some 3.3uF Mundorf Supreme caps. Well, the difference was a lot smaller then I expected, in fact, not much of a difference at all. Just a tiny bit more detail and air but nothing really special.
After that I tried just for fun some Jensen isolation transformers on the output. This cured some of the grain a little. I think due to the fact that it acts as a lowpass filter. I also tired a modified Yaqin CD3 Tube buffer, but as in my other experience with this buffer it does not do anything at all, completely nothing, zip, nada.
I have added a USB to spdif converter to the input and next step is that I would like to modify it with a volume control so the DAC can be used as a usb preamp for my kitchen system.
Since there is not that much difference between the active and the passive output in my case I'm thinking of going passive into a 47k alps volume pot and then use the opa627 as a buffer stage. Has anyone tried this ? Should i change the R37/R28 390 ohm / 510 ohm feedback resistor network to some higher values. These semm to be rather low for an opamp stage don't they.
Just recently I bought a Lite DAC AH very cheap just for fun. Alwyas wanted to try a NOS dac and this was the right opportunity.
After googling a little about the DAC it seems that it is a very inconsistnet piece of equipment. I have seen maybe 5 different types of opamps being used as well as capacitors, resistors, psu voltage etc. It seems that they trow in whatever was on sale at time of manufacturing.
Mine came with OPA627 (or a rippofF, who can tell), with standard metal film resistors, mkt caps, cheap elecrolytic output caps.
This thing was distorting like crazy at low frequencies, quite unbearable. But, it had good dynamics and "life" even with the compression effect of the thing clipping in. So I changed the output resistors from 270 to 150 ohm as recommended everywhere. This was no good, all the "life" was rubbed out of it, dynamics just average and everything sounded too polite, thin, weightless, completely boring sound.
So I changed the resistor several times and in the end settled on 225 Ohm (150ohm with 75 ohm in series) and this was the best compromis. No distortion and still a good portion of that life like sound. Still not perfect though so I tried the passive od, direct out via some 3.3uF Mundorf Supreme caps. Well, the difference was a lot smaller then I expected, in fact, not much of a difference at all. Just a tiny bit more detail and air but nothing really special.
After that I tried just for fun some Jensen isolation transformers on the output. This cured some of the grain a little. I think due to the fact that it acts as a lowpass filter. I also tired a modified Yaqin CD3 Tube buffer, but as in my other experience with this buffer it does not do anything at all, completely nothing, zip, nada.
I have added a USB to spdif converter to the input and next step is that I would like to modify it with a volume control so the DAC can be used as a usb preamp for my kitchen system.
Since there is not that much difference between the active and the passive output in my case I'm thinking of going passive into a 47k alps volume pot and then use the opa627 as a buffer stage. Has anyone tried this ? Should i change the R37/R28 390 ohm / 510 ohm feedback resistor network to some higher values. These semm to be rather low for an opamp stage don't they.
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hello ,
on mine lite AH , I swapped recently the ugly and magnetic case with a little larger one , in aluminium . I found the sound rather different , more clean .
also I placed 7807 in place of 7806 , for DAC supply , to get heat dissipation lower than with 7808 .
the DAC is working with passive mod and C38/39 removed , and it sound extremely good .
on mine lite AH , I swapped recently the ugly and magnetic case with a little larger one , in aluminium . I found the sound rather different , more clean .
also I placed 7807 in place of 7806 , for DAC supply , to get heat dissipation lower than with 7808 .
the DAC is working with passive mod and C38/39 removed , and it sound extremely good .
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