CS8416/CS4397 board at 96kHZ?

[jonners]

I recently bought one of these cheap CS4397 dac boards from Hong Kong:- See http://lampizator.eu/LAMPIZATOR/LAMP...ampizator.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.)

[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.

[jonners]

Thanks for your help. I'll give that a try.

[jonners]

Excellentissimo! All sampling rates now working, and 96kHz sounding very good. Thanks a lot for your help.

[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

[jonners]

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?

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

[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

[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.

[jonners]

Originally posted by wowly



Thereby, can you give us an brief description of the sonic performance of this DAC?

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

[wowly]

Well, thanks for all these answers. I'll post our efforts later on DIYaudio

Wowly