My NAD C515BEE is finished.............

[Bill Fuss]

Originally Posted by nad

Well Bill Fuss, you may be onto something there. Only a few hours after saying it's finished, I've been contemplating adding 3 more toroidals for the dac and opamps, changing more diodes, resistors etc etc. When will it be complete?? my answer would probably be 'never', but who knows?

I might start on my Meridian next??

But then I might not and go back to the 515bee and go for a discrete output, any recommendations??

That really depends on the dac chip, whether it is voltage or current output. IMHO, the implementation of the chip is as important as the particular chip used.
I'm a recent, fervent convert and promoter of using line OP trafos with voltage out dac chips, the simplest and most direct way of extracting everything the chip has.
For I/V conversion, jfets are hard to beat. Spencer had some inexpensive kits a while back that he has recently redesigned that are relatively easy to implement. Borbely also has a kit but they are much more expensive. There are many others too.

Have fun, that's what it's all about, Bill.

[Andrea:]

Well yes implementation is crucial of course... but for first the DAC chip has to be one whose sound I like (me, I like a lot the sound of Crystal chips).


Also, I don't mind opamps at all... but as few as possible and chosen among the (real) best (meaning not necessarily those most popular in forums ).

[nad]

Originally Posted by Bill Fuss

That really depends on the dac chip, whether it is voltage or current output. IMHO, the implementation of the chip is as important as the particular chip used.
I'm a recent, fervent convert and promoter of using line OP trafos with voltage out dac chips, the simplest and most direct way of extracting everything the chip has.
For I/V conversion, jfets are hard to beat. Spencer had some inexpensive kits a while back that he has recently redesigned that are relatively easy to implement. Borbely also has a kit but they are much more expensive. There are many others too.

Have fun, that's what it's all about, Bill.

Thanks for that.

I'm unsure if you read a recent post by amc184? but he's kind of disheartened me in my nad, would have been more honest to say he thinks it's a bit crap.

But, and a big but, I thought that's what it was all about? get something and make it better? most of the enjoyment I get is actually playing with the thing, not sitting there afterwards analysing the output.

The aim is to make it sound better whils't having fun with the iron, but if there is little difference afterwards then so be it, if there's a increase in musical enjoyment, then that's a bonus.

On the other hand, if I want to sit and 'enjoy' the music, then I'll power up mr Boothroyd and 'plonk' a disc in the destiny.


Chow

[nad]

Originally Posted by Andrea:

Yup it would be interesting to know what DAC it uses exactly, because that's what sets the potential of the player mostly.

24/192 covers a lot of things... personally I've heard an AK4385, and I thought it sounded much worse than the CS4398.

Hello Andrea,

The D/A is the CS4392. Is that good, bad or the ugly???

[nad]

Originally Posted by amc184

I'm glad to see that you got the player going.

What model of DAC is this player using?

It's the CS4392.

[Andrea:]

It's good, maybe better than expected actually. It's a good basis to play with.

[nad]

Originally Posted by Andrea:

It's good, maybe better than expected actually. It's a good basis to play with.

Thanks, good news. Is there a 'better' pin compatible D/A out there?

[Andrea:]

Hmm, I haven't checked but I doubt that the CS4398 is pin compatible.

Anyway I don't think it's limiting to have the CS4392 and not the CS4398 in this kind of player.


BTW, in my opamp tests I found the LME49720HA to sound quite well paired with the CS4398 -- it was one of my absolute favorites.

Maybe you could try the OPA1612 too.

[nad]

Originally Posted by Andrea:

Hmm, I haven't checked but I doubt that the CS4398 is pin compatible.

Anyway I don't think it's limiting to have the CS4392 and not the CS4398 in this kind of player.


BTW, in my opamp tests I found the LME49720HA to sound quite well paired with the CS4398 -- it was one of my absolute favorites.

Maybe you could try the OPA1612 too.

Great stuff, thanks.

Just been looking at the dac supply regs. There's 2, 1 drops the 10v input to 5v (KIA11117S55) and into a KIA1117S33 (down to 3.3v) to supply the D/A.

Thinking of pulling them out and swapping both for a single 3.3v ClassD discrete module, what do you think??

I use the ClassD regs for the opamps and what I thought was the D/A supply, but it's not...... oops.

[Andrea:]

Don't know well that stuff... I will just say that I don't think the usual regulators are a big limiting factor for sonic quality. Maybe only in extreme high end audio (the sort of thing we usually see as pure craziness)

I would be more concerned about the quality of the electrolytic capacitors in the power supply lines. Upgrading these can be very cost effective. I personally like the Rubycon ZL caps a lot (for their lifetime too).