Midiman Super Dac

Originally posted by davidcotton
Just had a thought. Would I be able to connect my pioneer dvd player to the optical input on the dac at the same time as having the cdp connected and would there be any benifit to doing this? Also wm suggested connection this to the coaxial socket I am assuming this is the spdif connection option?

Cheers.

David, yes you can have all the inputs connected, only the one being 'Seen' by the dac will be used, via the push in button on the left side of the unit.
 
David, obviously if you've already got an AV Amp, you'll want to send a digital signal from your DVD to the AV Amp. You'll probably do this with a Coax, thur leaving the DVDs Optical out free to hook it up to the DAC. This will let you listen to downmixed 2 channel soundtracks through the DAC if you want. This can give good results, and if you're not using a 5.1 (or whatever), set up, then is a good upgrade to MOvie soundtracks.

This is of course assuming the Midiman does 48khz ???
 
power supply parts list info please

wm i have just purchased s/dac and have changed jacks to rca,

i would like to have a bash at making a power surply rather than using supplied wall wart.

having a local maplins i would like to purchase

abs box ,the 9volt power surply unit, but would like to use a simular lead that goes from power surply to inlet of s/dac

but do not really know what all these items are called, could you if possible give me the maplins part no s of parts used.

abs box
power surply 9volt unit

connecters in/out of ps

and whatever the lead is called that goes from ps to back of superdac,

thank you
 
Personally, I would be more inclined to use a metal box for the psu (as I did) in order to provide some shielding for the transformer.

I can provide farnell part numbers for the bits that I used.

As for the lead from psu to superDAC... I used silver plated copper with ptfe insulation... however, when WM replaced a fairly similar solid silver lead on his with an omiga special, the difference was incredible. (On which note tone, I need one of those leads!).
 
Tones

Ever tried altering the loop filter of the CS8414?

Whilst there's a trade-off between lock-in and jitter attenuation, the Superdac as standard offers no jitter attenuation within the audio band, I wonder if this could be tightened a little in order to reduce this?

I shall be doing some of these mods soon, to a DAC I have on-loan. Initial impressions are that it isn't bad, but not that good either, as standard, fed from my DVD player.

The bit above may also explain it's sensitivity to transports, some work around the SPDIF input would no doubt be worthwhile too, to try and get a 75R wideband match, unlike the present configuration.

Anyone got the AKM4393 data sheet - I can't find it anywhere?

Andy

EDIT: Ignore DS request - I've found AKM's website ;)
 
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Andy, yes have done this 1k ohm .1% halcro, pricision film cap 47Nan fads, works a treat, but it needs a clean feed as the p1-a amply demponstrates, the PLL is no great shakes, mind you may not need it, seems Iaasc has erm um blown the dac chip :( (Power surge & not have a trip in the psu maybe) you can replace the stock item with another version, heard this not too shabby, I was going to do a N/C power supply for it, oh err. Tone
 
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OK, been a bit busy this afternoon, modding my friends DAC.

Changes are inline with others, various cap changes, rectifiers for the analogue stages op-amps for the unbalanced o/p's, adding phono's and removing the mute transistors and their effects.

First impressions are of a different animal altogether and that's using the stock PSU.

More later once it's warm.

Andy.

Superdac_mods.jpg
 
quality wire for for rca to pcb please.

hi all i got my superdac a while back and changed jack to rca phonos, but i used the only "wire" i had avaliable which was some cable from an old wall wart type phone charger,

as the wire is multistrand found it rather akward to get a neat soldered joint.

is there any small diameter solid core quality wire i can purchase say from local maplins to replace what i have used ,if so what should i ask for or if possible part code for said wire.

thank you
 
I'm impressed

By this groovy little box!

It's much better than I expected, but still behind my current CDP.

The next stage is to try and re-jig the loop filter around the CS8414 and change it from a 2nd order to a 3rd order response (and try and reduce the jitter peaking inherent to these PLL recovery circuits).

Struggling to find the relevant info at present, but for a clue, take a peek at this: -

http://www.eetkorea.com/ARTICLES/2001APR/2001APR16_MSD_AN4.PDF

A.
 
More room for improvement?

I've just realised the PSU's of this unit are a bit unconventional.

I was pondering the external wall-wart last night and realised it's 9V AC, yet the internal supplies for the analogue stuff are +/-15!

This thing must have a voltage doubler to produce a sufficiently high supply voltage to feed those reg's.

Think I'm going to have to take a deeper peek inside tonight, there may be dramatic room for improvement here, at the expense of needing a different DC input connector / transformer.

Andy.

P.S. PLL Loop filter change shows promise, more on that later...
 
Alas poor WM's superDAC. Yes, indeed I blew it up (weren't my fauly guvner!). However, we're reasonably convinced that the only part to have suffered any damage is the AK4393 DAC chip itself. A replacement one is on order, as is the higher spec AK4395 chip as well (192kHz part). Hopefully we'll have it fighting fit once more at the weekend.
 

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