i just wondering why using transformer with AKM dac output?
as i know AK4490/95/97 are voltage output which doesn't need IV converter.
the only need for the outputs are low pass filter to match the internal frequency response.
so AK4490/95/97 need LPF, is that output transformer act as LPF?
I finally received my test boards and built one to make sure that I had a proper handle on things. Everything seems to be working fine.
I wrote a piece of Arduino code to control pretty much every parameter of the chip that relates to sound quality for my single chip board. I've put it up on my blog.
It accepts commands through the serial port to change the various options. Here is its menu:
Next up is building a second unit so I can try dual mono operation.
What concerns me is the output stage. I've looked at the dual mono reference design for the 4497 part but I haven't gone as far as comparing the 4490's output characteristics with the 4497's so as to determine whether the 4497's reference design could be applicable to the 4490s.
I also don't like the 100uF capacitors in the signal path, before the summing of the signals. I would like to have full DC coupling if possible.
I'm a noob at analog electronics so any suggestions would be appreciated.
I'm OK with using op-amps but I would prefer something more "interesting", of the class-a discrete flavour. Balanced output would be preferable.
I wrote a piece of Arduino code to control pretty much every parameter of the chip that relates to sound quality for my single chip board. I've put it up on my blog.
It accepts commands through the serial port to change the various options. Here is its menu:
Next up is building a second unit so I can try dual mono operation.
What concerns me is the output stage. I've looked at the dual mono reference design for the 4497 part but I haven't gone as far as comparing the 4490's output characteristics with the 4497's so as to determine whether the 4497's reference design could be applicable to the 4490s.
I also don't like the 100uF capacitors in the signal path, before the summing of the signals. I would like to have full DC coupling if possible.
I'm a noob at analog electronics so any suggestions would be appreciated.
I'm OK with using op-amps but I would prefer something more "interesting", of the class-a discrete flavour. Balanced output would be preferable.
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wengtech - the AK4497 outputs a diferental signal also with dc (2.5v)
The transformer is just a very simple way to remove the dc & also obtain a single ended output (rca) if required. Depending on the transformer there may also be some hf filtering.
Dimdim - thanks for all the good info & link to your site. Well done!
Hey a couple of questions.
1. Has anyone experimented with "heavy load mode"?
It seems to be related to the analogue output stage so maybe it increases the bias on the output opamps. It may effect the output impedance??
Bottom line does it change the sound quality?
2. The digital core on the AK4497 (1.8v) can optionally be supplied by a internal regulator or fed with an external supply - I'm currently using the internal reg but just wondered if anyone has compared the two?
The transformer is just a very simple way to remove the dc & also obtain a single ended output (rca) if required. Depending on the transformer there may also be some hf filtering.
Dimdim - thanks for all the good info & link to your site. Well done!
Hey a couple of questions.
1. Has anyone experimented with "heavy load mode"?
It seems to be related to the analogue output stage so maybe it increases the bias on the output opamps. It may effect the output impedance??
Bottom line does it change the sound quality?
2. The digital core on the AK4497 (1.8v) can optionally be supplied by a internal regulator or fed with an external supply - I'm currently using the internal reg but just wondered if anyone has compared the two?
I finally received my test boards and built one to make sure that I had a proper handle on things. Everything seems to be working fine.
I wrote a piece of Arduino code to control pretty much every parameter of the chip that relates to sound quality for my single chip board. I've put it up on my blog.
It accepts commands through the serial port to change the various options. Here is its menu:
Next up is building a second unit so I can try dual mono operation.
What concerns me is the output stage. I've looked at the dual mono reference design for the 4497 part but I haven't gone as far as comparing the 4490's output characteristics with the 4497's so as to determine whether the 4497's reference design could be applicable to the 4490s.
I also don't like the 100uF capacitors in the signal path, before the summing of the signals. I would like to have full DC coupling if possible.
I'm a noob at analog electronics so any suggestions would be appreciated.
I'm OK with using op-amps but I would prefer something more "interesting", of the class-a discrete flavour. Balanced output would be preferable.
Want something interesting, use these: Home - Sparkos Labs.com
Sorry for my ignorance, but the chips are difficult to solder on the board?
I need specific equipment?
Arturo
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