Hello All,
I want to build an easy DIP socket type DAC, and Sanyo LC7881 looks very interesting to me. Easy build, few external components, native voltage -high impedance- outputs, but no standard i2s wiring compatibility.
I found this schematic on a Bulgarian forum. I don't know its author and I'm posting here within his/her tolerance. Any comments on circuit, especially i2s conversion on digital input section and additional info will be appreciated.
Regards.
I want to build an easy DIP socket type DAC, and Sanyo LC7881 looks very interesting to me. Easy build, few external components, native voltage -high impedance- outputs, but no standard i2s wiring compatibility.
I found this schematic on a Bulgarian forum. I don't know its author and I'm posting here within his/her tolerance. Any comments on circuit, especially i2s conversion on digital input section and additional info will be appreciated.
Regards.
Attachments
Last edited:
It seems interest on this chip is very limited. Maybe it is better to find a CD player based on this DAC for experiments.
http://forum.cxem.net/index.php?showtopic=7268&st=940&p=1020282&#entry1020282
Glue logic for LC7881 here.
Looks painful, and he does not show the SPDIF receiver used.
Glue logic for LC7881 here.
Looks painful, and he does not show the SPDIF receiver used.
Last edited:
The best part of the LC7881 is that it plays music. It has a relaxed non digital type of sound but is more detailed than a TDA1543 going from memory. It is not as detailed as some of the flagship DAC chips, but due to its pleasant presentation of sound it can be forgiven for its very minor lack of some detail. I also like this chip because every time I heard it, it produces decent bass, and balanced sound. Despite its minor limitations I believe a well designed board could sound very enjoyable. I even enjoy listening to it with op-amp outputs. I think a valve output would sound very nice..
The musical fidelity tubalog DAC was based on the LC7881 so to build a DAC will not be impossible.
Perhaps I have found an easy solution?
The NAD 5325 CD player uses LC7881 and YM3404B oversampling filter.
The complete d/a DAC converter list - DutchAudioClassics.nl
The YM3404B is designed to work with the YM3623B digital receiver
YM3404B chip for sale here
YM3623B chip for sale here
I found a pre made receiver board here
Is there any reason this wouldn't work? ( the picture is from the Ym3404B datasheet and shows a PCM56)
The musical fidelity tubalog DAC was based on the LC7881 so to build a DAC will not be impossible.
Perhaps I have found an easy solution?
The NAD 5325 CD player uses LC7881 and YM3404B oversampling filter.
The complete d/a DAC converter list - DutchAudioClassics.nl
The YM3404B is designed to work with the YM3623B digital receiver
YM3404B chip for sale here
YM3623B chip for sale here
I found a pre made receiver board here
Is there any reason this wouldn't work? ( the picture is from the Ym3404B datasheet and shows a PCM56)
Last edited:
Looks like an interesting chip - the main DAC is a string DAC, just like in the Metrum Octave and Hex. From the DS it looks like one advantage is there isn't an on-chip output opamp, other chips in the same family do have an opamp right at the output.
Look furthur down the datasheet. There is an op amp on the output. But yes, its a very good chip. There are a few different varieties of it. Some have digital volume control, and others have the oversampling filter built in - with the same DAC arrangement as the LC7881
I see a couple of schematics (p7 and p8) with output opamps, but these are applications not internal diagrams. I'm looking at a Japanese version of the DS.
Sorry my mistake. I went to edit my post and then the server went down for maintainance.
I think you are correct.
I bought some the other day. I will try to get it going.
What do you think about this glue logic stuff here
http://www.diyaudio.com/forums/digi...ourcing-sanyo-lc7881-via-i2s.html#post4132749
I think the Yamaha reciver looks much simpler. I bought some of those too
I think you are correct.
I bought some the other day. I will try to get it going.
What do you think about this glue logic stuff here
http://www.diyaudio.com/forums/digi...ourcing-sanyo-lc7881-via-i2s.html#post4132749
I think the Yamaha reciver looks much simpler. I bought some of those too
Hi abraxalito, have you any oscilloscope photos of your analogue filter's output characteristics for some particular frequencies like 1khz, 10khz, 20khz? Sorry for my curiosity but it would be interesting to compare the ones at link below:
Should I NOS-DAC ?
No I don't right now as I've not powered up the DAC that's using that filter yet. I'm still working on the PSU design for it. But its an excellent idea to do this so I'll get to it once I've done initial listening to the design.
I'm fairly sure when I get pictures they won't show any stair steps, due to the extreme bandlimiting effect of the filter. The 20kHz one will be the most interesting as it'll have some 24.1kHz images present around 20-30dB down.
I'm fairly sure when I get pictures they won't show any stair steps, due to the extreme bandlimiting effect of the filter. The 20kHz one will be the most interesting as it'll have some 24.1kHz images present around 20-30dB down.
Link below for the source of the scheme:
Upgrade of cdp vega-122
http://semigor2.narod.ru/KarDAC.rar
In this particular case no spdif was used as the dac was connected to I2s provided by pci soundcard with software upsampling.
Some more info on vegalab forum, the first search link:
https://www.google.ru/?gws_rd=ssl#newwindow=1&q=цап+LC7881
but unfortunately the forum will be available on Monday, the most probably (database maintanance).
Actually yes. I followed the tweak posted above (output stage of cdp) and it sounded good.
It was many years ago so impressions are not so bright and the whole system was not a high level (amp and speakers). In my opinion the chip has a significant potential (though not so popular and is not considered as high-end device). Would be very interesting to hear it again with respect to current preferences.
It was many years ago so impressions are not so bright and the whole system was not a high level (amp and speakers). In my opinion the chip has a significant potential (though not so popular and is not considered as high-end device). Would be very interesting to hear it again with respect to current preferences.
- Status
- Not open for further replies.