Hifimediy direct out cs4398 DAC

[Nick122147]

Hifimediy has started devloping a DAC with cs4398 chip and no output stage or LPF. Instead of adding cost with an output stage that some people will bypass to build their own or just go cap/trafo out, we will focus on only digital part and cutting cost by leaving out unecesary parts.

The background of this is several reports of Vout dacs sounding better direct out (with or without a cap or with trafo), or a simple lampizator style tube output stage.
I tried this last year and exerienced an increase in sound quality almost as big as when I switched from tube amps to tk2050 amp.

link to my post about direct out DAC:
New TK2050 board

Have been wanting to make a dac for this for a while, and we are now getting closer!
Yubing came up with this design as a start.
WM8805 receiver cs4398 DAC
no LPF or output stage
coax and optical input
It should work even without a output cap, but that might be depending on the amp.

What do you think?

Steinar

[sendler]

Make sure to include a high quality clock with DIR9001 or upsampling.

[alkasar]

Hi. Nice project for advanced diyers. I think of the people like me who use a laptop as source with no spdif output. Any chance to consider a top notch usb 96/24 input as well, based on Tenor TE7022L or similar ? this would certainly increase price quite a bit.

@scott : second the need for excellent clock.
wolfson WM8805 receiver has actually even better specs than DIR9001

[glt]

As a general diy kit, it would be nice to expose the s/w interface pins for both chips. Then some simple jumper/switch configuration can allow h/w or s/w mode.

A couple of cost effective improvements:
- A clock with its own low noise regulator feeding the WM8805 (rather than a crystal)
- A low noise regulator for the analog section of the DAC chip

[Bernie7]

To keep wiring short, provide some space on the board for the output caps or trafos.

[sendler]

Originally Posted by Bernie7

To keep wiring short, provide some space on the board for the output caps or trafos.

Probably not. Defeats the purpose of letting us choose our own output components.

[hifimediy]

Hi all, this comes from Nick's idea and he had very good experience with his none buffered DAC. So I think this is will be a simple DAC but with good chip set, and it will work good with class-T amps directly.

[Nick122147]

Hi all, and thanks for the input on this.

Yes, I think we definately should include a good quality clock.
We will also consider upsampling chip (in hardware mode)
I think we should make room on board for output caps (or trafos). we could supply it with output caps which would be very simple to remove if needed and add minimal cost, at the benefit of being plug and play ready.
USB input is also an option, TE7022L is an interesting option, but would add costs.

It might be an idea to make different versions of this DAC, using the same PCB but leaving out parts for different versions: no usb, upsampling versions, could be bypassed with jumpers.

[studiostevus]

I have modified a Behringer SRC2496 which uses AKM4393. To my ears, direct out from chip via some caps sounded best, cleanest...

Only disadvantage is relatively low output level.

[oon_the_kid]

One thing I think worthwhile adding is a digital volume control. This will allow direct connection from dac to tripath direct. The chip already comes with that built in. So might as well use it. I tried something like that once, I was using the inverting stage of the tripath chip as an IV converter for my Tda1541. Sounded pretty good but implementing volume control was a huge pain...

Oon