| jonners |
I recently bought one of these cheap CS4397 dac boards from Hong Kong:- See http://lampizator.eu/LAMPIZATOR/LAM...lampizator.html
Picture is at the top, scroll towards the bottom of the page for (incomplete?) schematic.
It works fine at 44 and 48kHz, but at 96kHz I just get a hissy noise. I consulted the Cirrus Logic CS4397 data sheet (bit out of my depth here, to be honest) and found that the mode operation settings on this board, which are M0=1 M1=0 M2=1 M3=1 M4=0, give 'single speed' (16 to 50kHz) I2S operation at up to 24bit. However, according to the data sheet for the Crystal CDB4396/7 Evaluation Board, these same settings give "Automatic Mode Operation'.
If anyone can help me understand what this means and suggest how to get it working at 96kHz I would be very grateful.
(The digital input, incidentally , comes from a Behringer SRC2496 upsampler. I've had it working with no trouble into other dacs.) |
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| error401 |
I'm not sure where you're getting that from the CDB4396/7 datasheet, it seems to indicate the same values in the CS4397 datasheet, which is what I believe is true for this IC. The results you're getting make perfect sense given that schematic.
I would normally expect a DAC using this IC/receiver combo to utilize the 96KHz pin on the CS8416 to select a high sample rate mode in the DAC when you apply such a signal. An obvious failing of the design. M4 is the CS4397 pin that puts it in high sample rate mode, you'll need to disconnect it from ground and apply an appropriate signal.
You will need to carefully lift the M4 pin (2) from the PCB (or cut the ground trace), and bridge it to the CS8416 96KHz pin (16) with a wire. This pin is an output so shouldn't be connected to anything and you won't need to lift it.
Your other option would be to just lift the pin and connect it to a switch to choose manually. I don't see why you wouldn't use the 96KHz pin though, it's not really any more difficult and is more usable.
All of this of course relies on that datasheet being correct, but from a quick glance at it I think it probably is, at least concerning the pins we're talking about here. |
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| jonners |
| Thanks for your help. I'll give that a try. |
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| jonners |
| Excellentissimo! All sampling rates now working, and 96kHz sounding very good. Thanks a lot for your help. |
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| wowly |
Well, how about that!
In holland, some members of the zelfbouwaudio.nl forum did a groupbuy with these boards, and were happy to see that there is a solution for this "design failure"!
Is it possible to make some picture's of you're modification, to ensure we will do the right thing to make this board up and running at higher samplerate's?
That would be very nice :)
Best regards,
Wowly |
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| jonners |
| quote: | Originally posted by wowly
Is it possible to make some picture's of you're modification, to ensure we will do the right thing to make this board up and running at higher samplerate's?
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It wouldn't be easy to show it on my present board because of other mods (caps) getting in the way. I have another board on order, so when that comes I might be able to do this mod first and take a picture that shows it.
It's fairly straightforward to do it, though: You have to unsolder and carefully lift pin 2 of the CS4397 away from the board. (Cutting the ground trace from pin2 won't work- I think it must connect to the ground plane in some inaccesible place under the board). You then solder a thin wire from that lifted pin to pin 16 of the CS8416. (No need to lift pin16).
My board will now switch automatically between 44.1, 48, 88.2 and 96kHz rates. I'm unable to test 192kHz, though.
Good luck!
John |
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| wowly |
Hello John,
Thanks for the very good explanation. It seems to be a quite easy way to do. Funny that you've mentioned the 192 Khz function, one of the members asked me if I've could ask you if the 192 Khz modus is functional....
Thereby, can you give us an brief description of the sonic performance of this DAC?
Anyway thanks for your effort!!
Wowly |
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| error401 |
As described, this mod probably won't work for 192KHz. The CS8416 doesn't provide a '192KHz' or similar output, so there's no way to detect if the sample rate is greater than 96KHz. The 96KHZ output will be asserted, but the DAC needs an extra input set low (M2, pin 4) for sample rates > 100KHz. To complicate matters, the M2 pin also controls de-emphasis in low speed mode (44-48khz). If you need 192Khz, you could try pinning the M2 pin low (or attaching a switch), but beware that if this pin is low in 44 or 48khz mode it will enable de-emphasis.
It might be able to receive 96KHz with M2 low too (datasheet says 100-200KHz), so maybe it's worth a try. |
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| jonners |
| quote: | Originally posted by wowly
Thereby, can you give us an brief description of the sonic performance of this DAC?
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Not very good at audiophile-speak. Ummm..... I like it! :)
Further discussion has been going on here: http://theartofsound.net/forum/showthread.php?t=315
John |
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| wowly |
Well, thanks for all these answers. I'll post our efforts later on DIYaudio :)
Wowly |
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| Rafoo |
Hello ! I've got a question about this dac.
Where goes the jumper ? Lukaz fikus says it goes in the corner but it is originally in the other position. |
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| jonners |
| Hello Rafoo. The jumper goes in the corner position for electrical input. The other position is for optical input. |
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| Rafoo |
| Oh, ok thank you very much ! |
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| pftrvlr |
I have both the small and the big versions of this DAC. And I connected the 8416 pin16 to the 4397 pin2 on the big DAC last night, it worked great with foobar 2K upsampling.
I will do the same thing to small one. |
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| Leeuwarden |
| Maybe a stupid question but does it sound better/different after connecting pin 16 to pin 2? |
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| pftrvlr |
| It does sound slight different with or without upsampling in fb2k. But most importantly, it will accept 24Bit-96K signal. |
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| kanifee |
Just bringing this back up to see if you tryed this on the smaller DAC
if so was it a success?
Am i correct in thinking that this is what you have done, and the pins that are joined either need there traces cut on the PCB or lifted form the PCB?
if what im reading is correct this solves the issue with the 96khz problem yes? also the chips are capable of 192khz, what you discuss earlier in the post does that mean the setup is incapable of the 192khz or rather it may be possible but there is no way to know if it is running at this frequency?
pardon me i have little klnowladge about amps etc and even less about DACs, my dac the same as this will be due to arrive next week so im just making sure im set for all the modding! |
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| error401 |
Your picture looks correct. You only need to lift the pin on the CS4397, but no harm will be done if you lift both.
The problem with this setup for 192KHz is that the DAC chip needs to be told whether you want it to work at ~44.1KHz, ~96KHz or ~192KHz, and the board isn't set up to detect that and inform the DAC. That's actually what the described mod does in fact, it allows the S/PDIF chip to tell the DAC it needs to run at 96KHz or 44.1KHz - but the S/PDIF chip unfortunately doesn't provide a similar output for 192KHz.
You could wire it with a switch and set it manually and it should work, or you could permanently set it for 192KHz (but this will prevent it from working at 44.1/48KHz, and probably for 96KHz too). This board can't work automatically detecting 192KHz. |
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| kanifee |
Ah i see, so its a case of being unable to have an automatic switch function built in, seems alot simpler now :D
I don't mind a switch on the front of the case to enable high bit mode so this isnt an issue,
One last question for you, if im not mistaken i read the unit needs to be jumper'd to switch between optical and coax operation, would it be simple enough to just fit a front panel switch to that aswell and would i need to worry about isolating the switch from the chasis or anything like that?
Thanks again for your help! |
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| Rafoo |
I'm trying to connect my dac directly in I2S, not in spdif so withot the CS8416.
I've read the datasheet of the cs4397 and I think I've found what to do :
Connect serial data to sdata pin
Connect bit clock to sclk pin
Connect word select to lrclk pin
connect ground to s ground pin
I think I don't need the master clock on the cs4397 which was originaly provided by the cs8416. But I have a problem : I think it will work fine from 32kHz to 48kHz, but since no signal is going throuh the 8416, nothing will be connected to M2. Do I have to put a switch to make it work at 96kHz and 192kHz or will it detect it by itself ? |
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| kanifee |
| Why would you bypass the other chip? what benefits do i2s bring over spdif? |
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| Rafoo |
| I save a conversion. I've got no spdif out on my laptop so I'm using a USB converter which has 2 outputs : spdif and I2S. I take directly the I2S and link it drectly to the dac instead of converting the signal to spdif and then to I2S. That is what I want to do, but for the moment I use spdif and it is working. |
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| aparatusonitus |
Hi Rafoo,
Which USB converter you are using? |
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| kanifee |
| ah i see, is there any quality differance between spdif/optical and usb or are they just digital signals so as good as each other? |
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| Rafoo |
I'm using the diyparadise one, it is in the diy module section and you have to solder averything by yourself exept the chips.
About the quality différence I don't know, I assume that it is the same as the signal is digital in every cases. I think you lose quality with the conversions more than with the format of your signal. |
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| kanifee |
| Can any one help with what size transformer this requires, was thinking of a 100va 2x16 volt? The psu board supply's + and - 12v and 6v to the dac |
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| error401 |
100VA is definitely overkill. The digital parts use < 100mA @ 3.3V and < 50mA @ 5V. Being generous, that's less than 1A @ 16V input, or 16VA. The opamp uses well under 100mA @ +/-12V, if you're even using it - 150mA at +/-16V for another 5VA. These numbers are very conservative, you'd be fine with a 25VA or 50VA trafo.
16V is probably a bit high too, but it's the most appropriate common voltage (or 2x15V). |
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| kanifee |
Spot on, Didnt think it would be very big but i wasnt sure how to work it out so i thought better safae than sorry, though thats just saved me £10!
Just chcked the shop, they only do 20va or 50va, 20va still fine yes? |
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| error401 |
| quote: | Originally posted by kanifee
Spot on, Didnt think it would be very big but i wasnt sure how to work it out so i thought better safae than sorry, though thats just saved me £10!
Just chcked the shop, they only do 20va or 50va, 20va still fine yes? |
Probably fine, but it may be loaded fairly heavily. If you want to know for sure, you can measure how much current the DAC draws at each voltage and we can work out how much power is being used. I suspect 20VA would be sufficient, but it's below my (conservative) estimate, so I'd rather measure to be sure. |
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| vaclavus |
___"The problem with this setup for 192KHz is that the DAC chip needs to be told whether you want it to work at ~44.1KHz, ~96KHz or ~192KHz, and the board isn't set up to detect that and inform the DAC. That's actually what the described mod does in fact, it allows the S/PDIF chip to tell the DAC it needs to run at 96KHz or 44.1KHz - but the S/PDIF chip unfortunately doesn't provide a similar output for 192KHz.
You could wire it with a switch and set it manually and it should work, or you could permanently set it for 192KHz (but this will prevent it from working at 44.1/48KHz, and probably for 96KHz too). This board can't work automatically detecting 192KHz."---
HI, I'm sorry if my questions will be too simple - how exactly can I set permanently for 192KHz ?
Thanks in advance.
Vaclavus |
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| adamus |
if i get rid of the on board output caps, am i right in assuming this will need rather small replacements. This iwll be feeding my headphone amp and will see a 50k pot.
suggests a value of under 1uf? |
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| adamus |
crickey, reading that back you wouldnt know i was english!
Basically i am asking what size cap i will need to prevent any bass roll off. I will remove the output caps and jumper the pads, then hook up some output caps directly to the RCA connectors. |
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| jonners |
| quote: | Originally posted by adamus
Basically i am asking what size cap i will need to prevent any bass roll off. I will remove the output caps and jumper the pads, then hook up some output caps directly to the RCA connectors. |
1uF into 50k should be OK at the low end, but are you intending to take the output via the caps direct from the CS4397? If so, you will get some ultrasonic noise which may upset your amp and appear as hiss. I took a balanced output direct from the CS4397, but I added some passive HF filtering. That works well.
John |
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| kanifee |
| What id like to know is how you would fit a switch to manually select the frequency? |
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| error401 |
| quote: | Originally posted by vaclavus
___"The problem with this setup for 192KHz is that the DAC chip needs to be told whether you want it to work at ~44.1KHz, ~96KHz or ~192KHz, and the board isn't set up to detect that and inform the DAC. That's actually what the described mod does in fact, it allows the S/PDIF chip to tell the DAC it needs to run at 96KHz or 44.1KHz - but the S/PDIF chip unfortunately doesn't provide a similar output for 192KHz.
You could wire it with a switch and set it manually and it should work, or you could permanently set it for 192KHz (but this will prevent it from working at 44.1/48KHz, and probably for 96KHz too). This board can't work automatically detecting 192KHz."---
HI, I'm sorry if my questions will be too simple - how exactly can I set permanently for 192KHz ?
Thanks in advance.
Vaclavus |
Disconnect CS4397 M2 (pin 4) from 3.3V and connect it to ground instead.
To fit a switch, use a pull-up resistor and a switch to ground. If you fit switches to M2 and M4 you can choose any speed. |
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| adamus |
| jonners, have you got a diagram? |
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| jonners |
| quote: | Originally posted by adamus
jonners, have you got a diagram? |
I based my arrangement on this: http://www.jensen-transformers.com/as/as093.pdf
Instead of the transformer you would have your volume control pot, and with series 1uF caps you don't need the offset circuit.
If you are going single-ended instead of balanced you could just try 250 Ohms and 1uF in series with the +ve output, followed by 2n2 cap to ground. |
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| adamus |
I have boxed this up in a temporary card board box.
Sound good... but when there is noise when turned up.
Its not typical white noise, more like a constant crackle if that makes sense.
Any ideas where to look? its not the opamp (swapped opamps and it remains).
Cheers
Adam. |
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| adamus |
actually, i think this is a ground loop manifesting itself as a slightly higher pitch sound to what i am used to with a loop.
I hate ground loops! |
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| adamus |
Edit - problem solved.
no noise anymore. The cheap transformer just needed moved further away. |
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| kanifee |
Hi, got my transformer today but seem to be having a wierd issue, plugged my tranny up and powered the psu board for the Dac on to check voltages and im getting 5v on the 5v rail, +12v on the +12v rail but -14.7v on the -12v rail.
Any ideas as to what could be causing this, i dont want to plug the DAC board up untill i get it sorted. |
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| adamus |
| dead regulator? 14v sounds like the sort of voltage the tranny is putting out un regulated. check the legs, there should be no shorts. |
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| kanifee |
No shorts as of i can see, tranny is a 15v but is putting out 17, looks like im gonna have to grab another regulator!
Just looking through maplins catalogue, the regulator in the dac board is a l7912cv, is it replacable with any of these.
http://www.maplin.co.uk/Module.aspx...gative&doy=20m8 |
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| kanifee |
| update* replaced regulator and its spot on now. |
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