Superdac picture gallery (post modification)

I thought I'd post up a few pics of the internals of the superDAC, post surgery.



The overall shot of the DAC and output stage. All of the purple (in real life... blue in the picture) OSCON capacitors are new, as are the red Elna Starget caps. Also, the single-ended outputs are now driven by AD825 op amps:



I do have a plan for a much neater, better way of mounting these. These drive the unbalanced outputs on RCA sockets:



All of the new big caps in the psu section are working with new schottky diodes, the remarkably hefty 1N5821:



Again, I have come up with a plan for a better way of mounting these.

From the outside, the new sockets:

 

Isaac,

Looks good. I have seen some adapters that you can mount SMT op amps on and plug into the regular op amp sockets on the web somewhere. I'll try to dig up a link if I remember where I saw them.

So what does it sound like then?

 

I'm building some little converters that will sort the probs with the 825s (for free as well, as I have all of the materials).

It sounds good. The caps and diodes made a serious amount of difference. Very tight, fast and authoritative now, and more detailed. Work to be done on the transport now, and a new amp is in order...

 

Iaasc, you should have asked, I have 825 and others all ready mounted on wilmslow adapter boards, do you not find that having the caps 'sat up' will not give the full benefit ?
Do you have a spare 16v 2200uf, the only one I haven't changed ?. Wm

 

The 2200uF is too tall to stand up in the superDAC casework.

Yes, I have 4 spares, since the MOQ was 5 (bit of a pisser, since they're about £3 each...). Might drop by tomorrow if that's ok? (I have the day off, and need to come in to town to do a few things anyway)

 

Iaasc, I'm in the office between 8.30-10.30 then after 4pm Ok, I got all the others to sit together no problem & the said cap I ordered (which didn't arrive, would fit)
I have the photo's at work, so I can't put them tonite.
Looking inside yours, I wonder if it's a earlier model, I know it's rev 3, but there's a few thing's I've spotted different. Wm

 

Here is Wm's almost finished one, the pictures arn't as good a Iaasc, he knows what he's doing with a camera , but I used small adapter boards to mount the smaller package opamps, and managed to get round the cap mounting problem.

 

Are those muting transistors next to the unbalanced outputs?

 

Warren you know, they might be, as it's a pro derived, the balanced output is a good +6db, rothwell attenuators anyone

 

If those are muting transistors (it's easy to figure out) I'd be temped to wire in some relays to replace them.

 

On monday I did actually discuss the transistors with WM, believing them to be muting. It might be possible to remove them outright. There's also a resistor in between the op amp and the output, which could well have an effect if it were improved....

 

Isaac, I normally just rip out the muting transistors in any component I'm upgrading. If you try it be careful when changing inputs via the button on the front you may get a nasty sound for a second.

I've removed the muting transistors from many CD players, a mindisc deck and a couple of DVD players. Only one of those components made strange noises afterwards.
It was the mindisc deck. It makes the odd low level noise when changing tracks but that only lasts a split second.

I believe that the output resistor's main function is so that the op amp does not see a short circuit when muting.

Once I've removed the transistors and I'm happy for them to stay out I usually replace the resistor with something better and a value of about 75 ohms.

Give it a try.

 

The present resistors are 2200ohm 2% metal film. Nothing special at all...

In case you hadn't figured it out, the superdac offers enormous modding potential, for some serious improvements...

 

So compared to a standard midiman dac (ie mine) how big a difference is there? Also whats the budget likely to be when all the parts are taken in to account?

Not looking to do it right now (still getting used to the stock form, which is now sounding quite good since I've had it on 24-7 for a while) but to just get some ideas on how to spend any money I may get for chrimbo

Cheers

 

The difference between a stock & basic modded version like either Issac's or our part time project is quite large, and not a Tones difference either, however Here's the Crunch, TO maximise the work all ready carried out, it needs to be complemented with components of it's equal or better that means not just psu's but transports and cables, Iaasc was treated to this very graphic demonstration on monday.
We use a £1500 cdp (stocK) as basic transport, if we run a AES digital lead out to the dac and the run the snall anaolgue i/c's from the dac/cdp, the difference is pretty obvious, detail/drive/depth and dynamics, but bear in mind we arn't using richer sounds style cables, so please bear this in mind when contemplating going the trans/dac route, more boxes, more cables, and more expense

 

ah so it is a midiman...the flying calf was very highly thought of.

Anybody know what dac chip is used, the calf used a crystal I think which in the latest version was a 24bit.

Interesting to see there are not many digital logic chips?

I have an audio alchemy ddev3 on the way, so looking forward

how come you used sm opamps? looks like the 5534s are regular ones? any others fit the bill?

tempted to have a go myself...

 

The AD825 op amp is not available in a DIL format (ie like the 5534), but only in SMD8.

The DAC chip is an AKM AK4393 (it's the small surface mount one below the op amps). The digital receiver chip is a crystal CS8414.

 

the crystal interface is pretty ubiquitous, but I have never heard of the dac...

whats that chip on wms foto that says dac on it?
obviously not the convertor...not enough legs!

might be an idea to get a sticky on the whole midiman lark,.,..where to buy, poss upgrades, just to pull all the info into one thread....??

 

The chip that has DAC hand-written on it is a PIC, I think a 16C54 (obscured by the writing partially, so it could be another PIC). When I get my programmer working properly, I might download the program off it and see what it does, but I assume it just controls input switching and stuff. It's clocked from the internal PLL of the CS8414, if you're pondering the abscence of a clock crystal.

 

No Lt Cdr Data, this is the M-Audio Superdac that we are talking about here.
Blame Davidcotton he called it a miniman

I believe that the Audio Alchemy ddev3 uses a pair of Analog Devices AD1862 D/A converters and a Crystal CS8412 input receiver.