New HQ DIY DAC

[Deleted]

Something for the more adventurous. It even uses a SC PSU board, and I am sure that a JLH would not go astray either !
It should easily outperform those US$98 toys , but it would cost a lot more to build though !
Alex

[Will]

That looks very interesting, Alex. If that thing scales/mods as good as the SCHA, it'd make a cracking complimentary project.

Any other details, such as USB compatibility, the DAC it uses etc?

[Deleted]

Aug 29, 2009 16:57:49 GMT Will said:

That looks very interesting, Alex. If that thing scales/mods as good as the SCHA, it'd make a cracking complimentary project.

Any other details, such as USB compatibility, the DAC it uses etc?

Will
I haven't thoroughly read the complete article (part 1),but it seems unlikely to be available as a complete kit.
A few brief comments : 24/96 max. DIR9001, DSD1796 and OPA134s etc .2 Toslink and 1 SPDIF in, and
plenty of room for a JLH or PaulHynes regulator.
Most likely not available as a full kit,but will have to wait until next month's SC to find out for sure. RCS Radio should have PCBs.
Unless a short form kit as a minimum, I wouldn't be likely to build it, as I couldn't be bothered chasing bits from numerous suppliers.

To quote Allan Pagan:
Alex
I saw the mag in Altronics on Saturday, while getting some smd resistors.
Had to get the mag also.
I still need to sit down and read the whole article, just skimmed through it so far.
A few thoughts so far.
The DSD1792 is pin and software compatible with the DSD1796 with better
spec's :-)

Allan


P.S.
Apparently the design was restricted to 24/96, as an alternative to the DIR9001 that would handle 24/192 had specs that were twice as bad.

[Will]

Hmmm, interesting. The main chips come to £20 from Farnell (SMD version), with the other 134's (I/V?) sitting in the parts bin. If it's a single sided board (unlikely, but you never know) then board manufacture would be straightforward, otherwise time to learn how to home etch double sided!

Why am I thinkingabout building another DAC? I hope I haven't caught DAC-itis from Leo!

[Spirit]

I'll take your 32S off your hands *any* day of the week Will ;D

[Will]

Aug 30, 2009 8:24:19 GMT Spirit said:

I'll take your 32S off your hands *any* day of the week Will ;D

What? Sorry? Cant hear you, mate?! (fingers in ears!)

[Spirit]

Aug 30, 2009 13:26:28 GMT mrarroyo said:

Get in line! ;D

I am! First!

[Deleted]

If anyone would like a little further information about this new SC DAC construction project, feel free to send me a PM. There may not be a kit available, but we will have to wait until next month's magazine for further information.
Alex

[leo]

Would make a nice Rockgrotto project eh fellas go well with your SCHA's too ;D

Thanks Alex for the Mail

[Will]

Aug 31, 2009 8:41:56 GMT leo said:

Would make a nice Rockgrotto project eh fellas go well with your SCHA's too ;D

Thanks Alex for the Mail

Couldn't agree more! The SCHA thread, in it's time, was awesome, and it'd be nice to have something like that back again.

It looks pretty straightforward, with a few options that could be removed if not needed. Plenty of bodging potential in the I/V section as well, using different op-amps/transformer coupling/fully discrete and not to mention the PSU capabilities.

I hope they do a kit, it would really help the project take off, I think.

And how nice would it be if someone made a USB/spdif circuit that was easy to make, to bolt on to it ;D (interest check...)

[pagan]

I still wouldn't use the DSD1796
The DSD1792 is pin/software compatible
better spec's (similar to the pcm1794)

That is, If your going to solder the surface mount devices to start with.

Leo has a suitable discrete i/v...... (Thorston's buffer modded for current)

The 24/96 limitation, is the DIR9001

I'd use the WM8804 receiver. www.wolfsonmicro.com/uploads/documents/en/WM8804.pdf

you gain 24/192 but loose multiple inputs.
Cannot understand why they selected the DIR9001.
Yes better jitter spec's to the CS8416 but the DIR9001 is restricted to 96K. for a DVD DSD dac?
WM8804 has better spec's than the DIR9001 but only a single input.
Big deal, input's can be selected by relay.
and they still not using an input tranny for spdif anyway.

allan

ps I'm waiting for the layout, next issue.
Just noticed, TI's evaluation pcb uses a CS8614 instead of there own DIR9001?? Why??

[Deleted]

That is, If your going to solder the surface mount devices to start with.

Allan
They don't appear to be using SMD devices,but we will need to see the layout and other photos next month..
Farnell has the DIR9001 and DSD1796,as well as the DIL OPA134, but the others are both SM .Farnell also has the xtal for under $2. A SPDIF Input transformer would be easily retrofitted.
You are a digital "snob" !
There is very little available software available at higher than 24/96, except for a couple of DVD-As which can be ripped.
SACD can not be ripped to .wav files AFAIK. This makes the DIR9001 a valid choice.
I believe this project should be capable of coming close in performance to my X-DAC V3.
I would use the existing analogue board , but reduce the voltage to +-12V, and everything fed via a dual JLH.
This would permit the use still of the OPA134, but allow the use of SM AD8065 on adaptor PCBs. I would remove the added filter stage,and use the much simplified circuitry of the X-DAC V3 with it's much gentler filtering. Many resistors would simply be replaced by links.

Alex

[pagan]

The DSD1796's are only SSOP's
focus.ti.com/docs/prod/folders/print/dsd1796.html

# Supports Both DSD and PCM Formats
# 24-Bit Resolution
# Analog Performance:

* Dynamic Range: 123 dB
* THD+N: 0.0005%

# Differential Current Output: 4 mA p-p
# 8× Oversampling Digital Filter:

* Stop-Band Attenuation: –98 dB
* Pass-Band Ripple: ±0.0002 dB

# Sampling Frequency: 10 kHz to 200 kHz
# System Clock: 128, 192, 256, 384, 512, or 768 fS With Autodetect
# Accepts 16-, 20-, and 24-Bit Audio Data
# PCM Data Formats: Standard, I²S, and Left-Justified
# DSD Format Interface Available
# Interface Available for Optional External Digital Filter or DSP
# TDMCA Interface Available
# User-Programmable Mode Controls:

* Digital Attenuation: 0 dB to –120 dB, 0.5 dB/Step
* Digital De-Emphasis
* Digital Filter Rolloff: Sharp or Slow
* Soft Mute

# Compatible With DSD1792 (Pins and Mode Controls)
I like this.

only limited to 96k by the DIR9001, just for the sake of multiple inputs over jitter?

[Deleted]

Supports Both DSD and PCM Formats

So ? SACD prohibits Digital OUT

[leo]

Certainly need to see the layout , of course the price needs to be good too, theres some very stiff competition out there at the moment

[Deleted]

SC DAC

At last, some more info, including comments from the designer.

forums.overclockers.com.au/showthread.php?t=810680

[Will]

Some interesting information, especially the jaycar short form kit with pre-soldered SMD's, and also an interesting comment from the DAC designer as to whether the modified SCHA at 'the rock grotto' is actually better than the original version, due to SC being very picky about SQ?!

Good old Phil then points him in the direction of 145 pages of SCHA modding!!

[Deleted]

Comment from a DIYAudio member yesterday.

Today, 06:44 PM #7
ianrt
diyAudio Member


Join Date: Jan 2008 Silicon Chip DAC Project

--------------------------------------------------------------------------------

I've read the article in SC

The DAC project is a good one, but not a very good one.

It uses a DIR9001 re-clocker and a DSD1796 DAC providing up to 24/96k decoding.
It has separate power supplies for analog and digital sections (although these use the one transformer and diode bridge)
Output stage is per 1796 datasheet but the project allows for the use of OPA134 instead of NE5534, and is single-ended only (without the pcb layout it is difficult to know how easy one could mod it for balanced output but it should be do-able)

Output frequency response starts falling above 24kHz (but if modded for balanced output you might be able to shift this up to 70kHz)

There is some strange problem (perhaps from using the one analog ps for both channels) that reduces crosstalk performance by 20dB at 10kHz and 30dB at 20kHz. Again without seeing the pcb layout I don't know whether separate supplies are easily adopted for each channel to try to fix this.

This project would be OK for anyone who doesn't have an outboard DAC to improve sound from mid-level CD players or PC-based material but if you're looking for top performance, try elsewhere.

I hope this helps.

www.diyaudio.com/forums/showthread.php?p=1926778#post1926778

Back to Top 122.107.122.174



Regarding the channel separation issue: If I do build it, I would be using a dual JLH without the CL enabled, in line with the Regulated +-15 ,+5V supply. I expect that the very low output impedance of the JLH would get around that claimed problem.
In any case, that claim is only based on the limited information so far available. I also think that the present output filtering is more than likely based on measurements at the SC lab, rather than ultimate sound quality, and higher rolloff frequencies should be readily obtainable without losing too much in the way of ultimate specifications.
Alex

[Deleted]

The SC DAC will be available from Altronics as a complete kit, including professionally punched and labelled metalwork. Kit no. and price T.B.A.
Jaycar will be supplying short form kits with all PCBs and components, but not other hardware such as case and PSU PCB and transformer etc.
KC-5487 is quoted as AU$139 , but the advertisement only shows the DA board, so this needs clarification, as IMO this sounds too good a price.
Alex

[Will]

No info as yet with that part number on the UK jaycar site.
Seeing as it was cheaper to buy through the site than buy via one of our Australian friends, it'll be interesting to see what's in the kit, and for how much.

[Deleted]

Hi Will
The kit does not appear on the Jaycar Aussie website as yet.
It is possible that the designer may present a 24/192 capable version later on, after some less than subtle on line pressure from guess who. Although more recent comments may piss him off.
Alex

[Deleted]

I asked at Altronics Sydney store this morning,and was told that the kit is due for release later this month. There is no info on their website yet, but I was given the catalogue number as K5332

SandyK

[robertkd]

Be buggered with the DAC did you see the USB interface to borrow a line from Mike i nearly tented up over it

Any way got one on order and waiting for delivery, brushing off the rust and scale from the C++ and assembler,...

Oh alright maybe the DAC has some potential

[Deleted]

Hi Robert
Great to see you back on line again.
I have checked both Altronics and Jaycar websites, and the SC DAC is not mentioned yet.
The best I could get was a new catalogue no. from Altronics when in there recently, but no further info on pricing or availability.
Are you a DIYAudio member.If you are quick there is a NZ/Aus GB for LME49710 (LM4562 single) at good prices. I am in for 30
Could be interesting to try in place of OPA134 s, NE5534 etc.?
Regards
Alex

www.diyaudio.com/forums/group-buys/153050-nz-oz-gb-nat-semi-lme49710-opamp-dip8.html

[robertkd]

you got a link to the thread??