Experience with this DIY DAC ?

[Bill Fuss]

Hi Guys

I have been asked by a friend who is interested in this DAC if there is any way of making it accept multiple spdif inputs that are switchable (like you can with the buffalo)

Is there a module that will work with the CS8416 or should he Get the DIR9001?

You can convert all 4 inputs to coax if that's what you are after. The 4 inputs on the 8416 are identical, and you can use the jumper matrix for switching with a 2 pole 4 pos rotary switch.

 

[Bill Fuss]

I thought so as well; just wondered if anyone had any first-hand experience with them (or the seller).

Yes, the 'specs' are spectacular- frequency response etc. are perfect. BUT, the $10.00 question is: how do they sound?

I may order this just because. Pricing is in line with getting decent trannies loose, and then having to mount them etc. The board appears to have provisions for caps and resistors as well if you look at the photo...

Elegant. If we are not careful, we will have a very nice product on our hands!

The specs are incomplete, but if you can return them if they are crappy then what the hell, try them.

 

[Bill Fuss]

Thanks Bill.

Does pulling USB/optical circuitry provide a worthwhile improvement in SQ?[/QUOT

Probably not , it would slightly lower the PS load though.

 

[Bill Fuss]

I found another donor candidate for trafos, the A R T DTI, dual transformer interface.
The specs on it are also incomplete but for $50 new it would be worth checking out, plus you get some XLRs. Let us know if someone tries it.

 

[RichLund]

You can convert all 4 inputs to coax if that's what you are after. The 4 inputs on the 8416 are identical, and you can use the jumper matrix for switching with a 2 pole 4 pos rotary switch.

Excellent Bill. Many thanks

 

[RichLund]

Has anybody established if it is a good idea to add a pulse transformer to the S/PDIF input. What harm can it do and what gains can be expected.

My source is a PC so I'm not sure if the output has a transformer already. I assume that the DAC has the transformer ommited in case a CD transport is used with one already fitted.

Thanks

Rich

 

[Graemedench]

I'm running pulse transformers on my inputs and from what I can tell from my scope there is no major degradation to the signal what it does do is gets rid of the 30-40v from my bluray and sky boxes

 

[Bill Fuss]

Yeah, aside from the isolation I don't think they help anything. You can screw up a trafo termination easier than a cap-resistor termination. Theoretically, if your terminations and impedances are right you should not be able to hear differences in sources. I have found that to not be the case so far, but YMMV.

 

[RichLund]

Thanks guys, I'll try a Sumlink ST-DV709 in there tomorrow. You don't know 'till you try eh?

If any body has a Newava SS22083 spare, I'd be interested.

By the way Bill, that dual transformer interface does look interesting. I'll recommend trying this to my friend when he starts considering output trannies.

Thanks again

Rich

 

[McCrackers]

I'm running pulse transformers on my inputs and from what I can tell from my scope there is no major degradation to the signal what it does do is gets rid of the 30-40v from my bluray and sky boxes

Can you please elaborate on the model and how it's connected.
Thanks

 

[Graemedench]

They are STC - PTABV- 8633

Each input has the output of three in parallel then going to a DPST relay that then feeds input 1 on the 8416

I know this isn't ideal but no obvious signal degradation on the scope.

This gives me an optical input and 2 coax in/outs or a coax in with isolated passthrough to feed my cyrus AV8 for surround duties.

Have a wee look http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac-225.html#post2120269

 

[RichLund]

Jesus Graeme, I am humbled by your expertise. I had seen that post previously but sort of skipped over it as it didn't seem relevant to me at the time. Hell of a job.

I'll be very interested to hear about your regulator section for the DAC sub boards. Improved regulation is something I've been thinking about, possibly using TeddyReg's if suitable.

Things I want to try:

1. S/PDIF transformer
2. Improved Regulators
3. PCM1798 DAC chip / DIR9001

 

[McCrackers]

Rich Lund pretty much sums up my thoughts also.

Tried the pulse trafo thing but I always felt I hadn't done it right so I removed it pending more explicit directives. I have a Newava and a Lundahl on standby for that. Wouldn't mind trying the regulator and PCM1798 mods either but there always seems to be pieces of the puzzle missing for beginners like me.

 

[Graemedench]

Thanks. Didn't get much response when I put it up so was a bit worried everyone thought it was cr@^.

Been on a bit of a go slow just now tbh.

My expertise is actually quite limited maybe not to some but I feel it is. What I do though is decided exactly what I want something to do then hunt out the kit that'll do it and plug away finding out the best way to implement it or find something that does it already then look at each section and try to improve it if possible. I find I learn alot that way.

Nice weather means I'm cracking on with rebuilding my kitcar (midas) Making a new wiring loom and fitting out all new eliectrics.
That coupled with I'm so happy with my HIFI just now even with the dac spread out in prototypes I'm not too spurred on with getting it all finished and finalised cause its working so well.

I've not started designing new regulator stages yet so it may be some time But I will post on updates. Hopefully get the little Audio buffer board done soon. Shouldn't take long then get cracking on the regulator section. Gotta keep it quite small though to fit in a Cyrus box. Not easy on veroboard and point to point wiring.

RS does a transformer that will go straight onto the origonal board. Oxford Electrical Products | Transformers | Transformers | Telecoms and High Frequency Pulse Transformers | Digital Audio Transformers |LAD 4613

Really need to sort out doing my own proper boards some time.

Let me know if I can Help. Happy to if i can.

 

[RichLund]

McCrackers - what did you feel wasn't right with the pulse transformer? I seem to remember a post with a pic showing a ceramic cap attached to the transformer. Some sort of RF filter? Will try to find it tomorrow.

I'd be happy to buy the Newava or Lundahl off you if you decide not to use one! I have a Sumlink which i believe are ok but not the best.

Graeme - how many regulators are needed if output transformers are used? Datasheets for CS4398 show 4 x 5V and CS8416 show 3 x 3.3V. The USB section would also need 5V. Does this sound right?

I guess selecting the right type of regulator circuit is pretty crucial when considering the voltage dropout etc. An extra power supply tranformer maybe needed. I like Teddyregs they seem to be very good and very compact. A new design is in the pipeline using SMD parts.

Cheers

Rich

 

[robob]

Hello,

I got a "BIG 24bit/192Hz NEW HI-FI DAC DIY KIT, ASSEMBLED MODULE" by Snow48_6 on ebay. This is the black model without USB.
I connected the DAC with a toroidal transformer 2 X 15V 0.67A, 9V 1.1A. When I plug the dac as well as in optical coaxial on my computer, I hear a click and then I have a little noise in the speakers (mass sound ? sorry for my english ).

I do not have this problem with my other DAC (Audiophonic PCM1798, translate very good one) and the same toroid and same source (computer).

I asked Snow48_6 for the good specification, He answered me :
single 8-10V / 500mA; double 13-15V / 300mA
Mine is
single 9V/ 1.1A; double 15V 0.67 A

May be too many amperage ?
any idea?

 

[manina]

Hello,

I got a "BIG 24bit/192Hz NEW HI-FI DAC DIY KIT, ASSEMBLED MODULE" by Snow48_6 on ebay. This is the black model without USB.
I connected the DAC with a toroidal transformer 2 X 15V 0.67A, 9V 1.1A. When I plug the dac as well as in optical coaxial on my computer, I hear a click and then I have a little noise in the speakers (mass sound ? sorry for my english ).

I do not have this problem with my other DAC (Audiophonic PCM1798, translate very good one) and the same toroid and same source (computer).

I asked Snow48_6 for the good specification, He answered me :
single 8-10V / 500mA; double 13-15V / 300mA
Mine is
single 9V/ 1.1A; double 15V 0.67 A

May be too many amperage ?
any idea?

I got mine from Snow as well - actually, mine was with USB however the transformer is the same and it works without any issues

 

[robob]

I got mine from Snow as well - actually, mine was with USB however the transformer is the same and it works without any issues

Wich transformer ? Mine is single 9V/ 1.1A; double 15V 0.67 A (got it here)

Snow is is selling this one : 8v/800mA 2X13V/500mA 20W AC (and says it is good for the big DAC)
and answer me this spec for the DAC : 8-10V / 500mA; double 13-15V / 300mA​

​

 

[Bill Fuss]

Your trafo is fine, check your jumpers.

 

[manina]

Your trafo is fine, check your jumpers.

Yes - as he says, it's OK.

How you setted the jumpers that are close to the 15-0-15?

Mine arrived setted for the digital electric one