Hi Weiliang, I have recently purchased DAC7 with Wolfson from another DIY member. It works great. Out of curiosity I measured it with my focusrite. It has very low distortion and great dynamic range, but not completely flat fr response. There is slight boost towards low end, and slight roll of towards highs. I was wondering if this was intentional, as other DACs I have have flat fr response.
Could you provide schematics of the output stage with opamps, I would like to see if by changing some capacitors I can make it flat.
Best regards,
Ed
ps: I was not able to send pm to you
Adason, I have a dac5, will try and find the schematic here, it used to be on another forum, but I didn’t see it after a quick search. These used the Arcam circuit but the feedback biasing of the opamps was not a welcome thing, might look at that first.
I’ve used a combination of different parts in mine, which is used exclusively in a headphone setup.
I’ve used a combination of different parts in mine, which is used exclusively in a headphone setup.
You might try and find the Arcam schematic and compare values as well.
I used a Russian polystyrene 1uf in the servo, and it cleaned up the muddy bass a lot. That and those Caddock output resistors.
I actually wound up changing nearly every cap in the thing to the point that I required another board. The filter around the opamps use a combination of Philips/EMZ polystyrenes and Wima mkp2.
Need to check the feedback bias on the opamps though, is not what you want likely.
I used a Russian polystyrene 1uf in the servo, and it cleaned up the muddy bass a lot. That and those Caddock output resistors.
I actually wound up changing nearly every cap in the thing to the point that I required another board. The filter around the opamps use a combination of Philips/EMZ polystyrenes and Wima mkp2.
Need to check the feedback bias on the opamps though, is not what you want likely.
I would try the CD17, schematics are available on HiFiEngine also, is where i looked to see if it was the circuit that used a servo…
Also might want to try it with better parts in the filter first(?)
Some of the measured distortion could be caused by the polyester caps possibly.
Also might want to try it with better parts in the filter first(?)
Some of the measured distortion could be caused by the polyester caps possibly.
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Distortion was very low, i roughly remember my loop was like 0.0020%, and with dac7 inserted it went up to only 0.0027%, barely anything.
Its the early rollof i want to fix. It started gently rolling at 10k, few dB at 15k, but steep at 20k. Almost looked like deemphasis on fm radio. I used to fine tune stereodecoders for 19k notch. This looked just like that.
I will search hifiengine, thanks for the tip phase.
Its the early rollof i want to fix. It started gently rolling at 10k, few dB at 15k, but steep at 20k. Almost looked like deemphasis on fm radio. I used to fine tune stereodecoders for 19k notch. This looked just like that.
I will search hifiengine, thanks for the tip phase.