And so it begins in earnest...

The superDAC has got off lightly so far... It's only been modified to give RCA phono outputs, and had a little dynamat added to the lid.

But now it begins in earnest.

I have ordered (to a total of around £100!!!) the parts to really give it a kick up the bottom...

The NE5534 op amps are to be replaced with Analog Device AD825s.

The 1N4001 rectifying diodes are being replaced with 1N5821 schottky diodes.

The 19 10uf 25V el cheapo VLSOM electrolytic caps (used for local psu decoupling around each op amp) are being replaced with extremely expensive Sanyo OSCON SG capacitors (These are no-expense spared capacitors... the legs are OFC!). At £1.45 a piece, this accounts for a very significant chunk of the upgrade cost.

OSCONs (this time SA series) also feature again, replacing the 470uF 16V psu caps, which are the main decoupling for the +/-15V regulators.

All of the larger psu caps (470uF 35V, 2200uF 16V) are being replaced with Elna Stargets, since OSCONs don't go this big, and Black gates would be seriously silly money (and only available from audiocon).

Further reports shall follow, with pictures...

 

Keep an eye on the voltage after you change the diodes. The schottky may allow a bit more through.

 

It is then regulated by 7815 and 7915 voltage regulators, so a small rise will be tolerated.

 

Lee, the regs handle it no problem although, your old dac & the ones I've done thus far, are using 50V decoupling caps around opamp arrays, so guys should please check before ordering. Wm

 

I'm suprised your keeping those noise makers. Wouldn't better regulation be a good thing. Something based around an LM317/337 perhaps.

 

Well, the DAC has survived the first stage of this round, which includes putting in the schottkys and all of the caps. The op amps will come later.

Obviously caps will take time to sort themselves out (couple of weeks I should imagine). However, early signs are good, with the mid much more transparent, and less recessed in general. Just generally less "fuzz"....

I will probably do the op amps (at least for the single ended outputs) tomorrow.

I will look into new Vregs later...

 

And I've done the single-ended output op amps now as well. After a quick bit of circuit tracing, I've identified some other bits that could do with some attention.

Sound....

Is this the same DAC? Yes, the qualities are still there (but stronger... grooviness is getting closer!), but the weaknesses are rapidly falling away (the haziness and fuzz are gone from the midrange, which is less recessed also). No, of course it isn't up to an ex-tone Wadia, but for the money spent so far (£100 for the DAC, £150 on parts for upgrades and psu) it is seriously good.

DOB in the player along with a few other mods there, and a couple more things in the DAC, and then that's that (for a month or two at least)...

 

Just curious really, which digi ic are you using at the mo? I'm currently using ye olde qed £20.00 that I bought around the same time as a sony je510 (yes that long ago!) minidisc deck.

 

Coax is a Trichord Pulsewire (on loan), and optical (for the computer) is a QED Qunex OT.

I intend to get a Digital Output Board installed into the cd player, which will give me an AES/EBU output, so the plan is to get something good once that's done, and not have to reterminate or end up with an expensive rca coax unused. I'll probably buy a reasonable (and reasonably priced) rca coax as tone will want the pulsewire back before too long I should think.... And I will need one eventually, as another part of the plan is that I'll buy a DVD player...

 

Iaasc your ok, I have one or 2 cables around, not really going to miss the pulsewire.
With a decent transport & wires it hauls itself up fairly well into the £1500 region, and an upsampler and it starts to really shine .Wm

 

Cheers Tone. If you want the ixos back, that's no prob...

Would be interesting to pitch your modded superdac vs mine once I've done a few more things...

Once the DOB is in place, and all that has settled down, the amp really is going to come in for some attention... at teh moment I've got a £1500 pair of speakers, and the front end is getting to higher heights than that, but it's all going through a £270 integrated.... a pretty GOOD £270 integrated, but I feel that there's (significant) improvement to be made in this area.