No lock noise
There will be a loud (full scale?) noise on the output of the dac chip any time there is no lock from a source.
There will be a loud (full scale?) noise on the output of the dac chip any time there is no lock from a source.
Yeah, I don't want that.
I think I will just test out the shorting relay idea and see if it makes any noise when shorting. I haven't checked the relay yet to see if it's DPDT or not (I think it is).
BTW, as it is right now my amp makes a lot of noise when the DAC doesn't have a signal because after the relay disconnects the two it leaves my amp inputs floating. There is no volume control right now, just a straight connection.
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i designed a CS8416 -> CS8421 -> CS4398 DAC with only passives and a transformer as an analog stage and I don't get nasty unlocking sounds when my source stops transmitting. I'm using an Apple airport express whose TOSLINK output goes black when music isn't being streamed, so I know the 8416 unlocks.
So without the relay, you may not have any noise problems.
Sheldon
So without the relay, you may not have any noise problems.
Sheldon
Relay by-passed
The mute function of the receiver is an output which controls the relay that is by-passed when running direct out.
The mute function of the receiver is an output which controls the relay that is by-passed when running direct out.
High gain I/V
Nice work. You are the pioneer of a high gain transformer I/V with the PCM1794. I will be interested to read your subjective opinion of the sound compared to a V out dac chip running direct out.
Pioneer..Wow!The first impression is a little laidback in the highs.But I will listen more and then switch to CS4398 and so on.
just received this Big DAC version 1.0 Lar Audio 2010,01
I have spent some hours on this thread but still have no good idea what mods would be best for this version.
Are there still any known bugs for this version?
What are the preferred mods?
Better filtering around the opamps?
Better opamps?
Transformers?
First I will start and buy a proper enclosure and get rid of the nasty job (mechanics ;-(( )
Hi End 24/192 DAC DA CONVERTER CS8416+CS8421+CS4398 USB - eBay (item 160496622438 end time Oct-24-10 15:05:13 PDT) is what I got
shows the main chips
end stage audio by pair of 5532
I have spent some hours on this thread but still have no good idea what mods would be best for this version.
Are there still any known bugs for this version?
What are the preferred mods?
Better filtering around the opamps?
Better opamps?
Transformers?
First I will start and buy a proper enclosure and get rid of the nasty job (mechanics ;-(( )
Hi End 24/192 DAC DA CONVERTER CS8416+CS8421+CS4398 USB - eBay (item 160496622438 end time Oct-24-10 15:05:13 PDT) is what I got
shows the main chips
end stage audio by pair of 5532
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Hi JB,
As far as bugs, there are a couple that I believe most, but not all, have ignored.
If you got the schematic with it, compare the 8416 PLL filter circuit with the recommended filter on the 8416 datasheet. I don't think they ever fixed it on previous versions, but a lot of us have fixed it on our own boards. I can't really tell you if it is audible though.
The power supplied to half of the 8421 upsampling chip is quite a bit over the manufacturers max voltage limit. There have been a few failures that required replacement by the vendors, but generally it doesn't seem to be as big an issue as I would have expected. That's another thing that they probably have not fixed.
As far as mods, if you dont mind opamps you can roll your own to your hearts content.
The standard dac chip itself has a 2v rms output that you can use directly through caps, through trafos, through tube or SS buffers or anything else you can dream up.
You can upgrade or completely replace any or all of the 8 different PS regulator circuits.
Most everyone that has posted in this thread has had their own goals and areas of interest for improving the board. If you ask direct questions about particular areas of improvement I'm sure you will get quite a few suggestions.
I personally don't have a single opamp in my entire system. I chose the output trafo solution, doing away with the entire output section on the board. The direct out solution with cap coupling is also appealing, especially if you have a balanced preamp input to feed.
Best, Bill
As far as bugs, there are a couple that I believe most, but not all, have ignored.
If you got the schematic with it, compare the 8416 PLL filter circuit with the recommended filter on the 8416 datasheet. I don't think they ever fixed it on previous versions, but a lot of us have fixed it on our own boards. I can't really tell you if it is audible though.
The power supplied to half of the 8421 upsampling chip is quite a bit over the manufacturers max voltage limit. There have been a few failures that required replacement by the vendors, but generally it doesn't seem to be as big an issue as I would have expected. That's another thing that they probably have not fixed.
As far as mods, if you dont mind opamps you can roll your own to your hearts content.
The standard dac chip itself has a 2v rms output that you can use directly through caps, through trafos, through tube or SS buffers or anything else you can dream up.
You can upgrade or completely replace any or all of the 8 different PS regulator circuits.
Most everyone that has posted in this thread has had their own goals and areas of interest for improving the board. If you ask direct questions about particular areas of improvement I'm sure you will get quite a few suggestions.
I personally don't have a single opamp in my entire system. I chose the output trafo solution, doing away with the entire output section on the board. The direct out solution with cap coupling is also appealing, especially if you have a balanced preamp input to feed.
Best, Bill
If you don't go with output transformers, then at the very least the LPF for the op-amp needs changed to the values outlined in this document....
http://www.cirrus.com/en/pubs/appNote/AN048Rev2.pdf
I have also removed the second op-amp and all of it's components, removed all signal coupling caps, added local supply decoupling to the LPF op-amp, reconfigured the muting relay to short the output to ground when muting, and replaced all the Sanyo caps on the output of the regulators with Panasonic FC.
Attachments
One word of warning. Be as gentle as possible removing components, the board traces are pretty fragile. For example, if a cap wont come out easily and you want to bypass it, just jumper across it with solder or a piece of wire. If replacing resistors, clip the leads off and solder the new one to them if they wont come out easily.
You might not have any trouble at all, I just thought this would be helpful.
You might not have any trouble at all, I just thought this would be helpful.
OK Bill, I will keep this in mind. I do have a Hako desoldering station
however when the holes are too small for the wires, it can still be difficult to get them out.
An externally hosted image should be here but it was not working when we last tested it.
however when the holes are too small for the wires, it can still be difficult to get them out.