I have a Pioneer DVL-909 which I hadn't used in a long time. I turned it on yesterday and it sounded surprisingly good. It lacked some transient bite but went very low and sounded very musical.
Now I want to upgrade the DAC section.
Would anyone have the schematic of the DAC section ?
Thanks.
Now I want to upgrade the DAC section.
Would anyone have the schematic of the DAC section ?
Thanks.
I discovered that the DVL-909 uses the PD2029AM DAC . I have no idea ifthisis a well regarded chip. The following circuitry seems to be a single opamp filter ( BA4560 ) . Very simple implementation.The best option I guess would be to completely bypass the onboard analog circuit and take off the audio from the DAC chip itself.
However there is a signal marked as AAL and AAR which goes to the BA4560 via a transistor . Wonder what that does.
Anyone?
Cheers.
However there is a signal marked as AAL and AAR which goes to the BA4560 via a transistor . Wonder what that does.
Anyone?
Cheers.
Attachments
The AAL/R lines are the analog audio path for the FM audio tracks of laserdiscs. The PDM2029 can sound great, but there isn't a lot of room where it's at in the DVL909 to help it out with bigger lytics & film caps on all of it's various power supply pins, but it's possible to make it a lot better than stock, nevertheless. There's nothing wrong with the single opamp output stage, other than the choice of chip & other parts. Essentially the same stage as in the PD65, which can be made to sound great. I've used my favorite B-B OPA2134 for this app with great results, using as much Nichicon lytic filtering on it's supply pins to ground, and as much film bypass caps as will fit the space. The output cap, of course, can be eliminated.
Pioneer DVL909
Some modification firms, and DIY ers take the O/P from the DAC , bypassing the analogue stage. If you are lucky,it MAY sound better . However, DAC chips are NOT designed to drive capacitive
loads like the typical interconnect. This will make the audio quality very dependent on the length and quality of the interconnect used. If you must do it, put a 100 ohm resistor between the DAC and the O/P jacks.
IMHO, NOT a very good idea.
SandyK
Some modification firms, and DIY ers take the O/P from the DAC , bypassing the analogue stage. If you are lucky,it MAY sound better . However, DAC chips are NOT designed to drive capacitive
loads like the typical interconnect. This will make the audio quality very dependent on the length and quality of the interconnect used. If you must do it, put a 100 ohm resistor between the DAC and the O/P jacks.
IMHO, NOT a very good idea.
SandyK
Thanks Guys. I was not planning on taking the signals out from the DAC directly. I am also not worried too much about the single chip implementation. However the chip is not particularly good.
I have some soic NE5532's and LM4562 and NJM4580's . Not sure if I can find the soic OPA2134's .
I was more inclined on adding a small pcb with an external filter circuit and connect that to the output sockets. Maybe a 4562 ?
If I were to just replace the chip , would the NJM4580 do ?
Hate to use up the 4562 unless I use the dip version and can remove it when required.
cheers.
I have some soic NE5532's and LM4562 and NJM4580's . Not sure if I can find the soic OPA2134's .
I was more inclined on adding a small pcb with an external filter circuit and connect that to the output sockets. Maybe a 4562 ?
If I were to just replace the chip , would the NJM4580 do ?
Hate to use up the 4562 unless I use the dip version and can remove it when required.
cheers.
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