My new, old DAC

[J!m]

So, about ten years ago I picked up an EBay DAC kit that was held in high regard over at diy audio.

I’m finally getting around to casing it up. I have tested it and it does function.

It uses an op amp output, so I picked up a few compatible replacements with better specifications to see if that is audible.

I also changed it from internal jumper position to external rotary switch for input selection. I’m adding a colored LED for each selected position for positive feedback of what is selected, even if you accidentally dropped your readers in the blender.

No copper this time (unless I do a copper knob) and the logo will be directly engraved into the black lace plate. (Unless it gets messed up, and then I’ll make it another silver face).

 

[laatsch55]

Nice..m

 

[VSAT88]

Nice..m

I would be interested in hearing what you have to say about the op amp rolling. I don't think I can hear a hell of a lot of difference when I did the same with my Kenwood C2's.

 

[J!m]

Well, the ones in there are the cheapest available in China ten years ago… I have three or four possible replacements in hand. Some are “audio” and the others are just fast and quiet. Once (if) I hear the best sounding one I’ll identify it. Right now the numbers mean nothing to me, but I did make sure they are drop-in (same pin-out and voltage)

 

[pioneercollector]

Very nice! And what a great way to get your hands on a DAC! Looking forward to the end results

PC

 

[J!m]

The actual converter chip is supposedly a decent one. But I found a drop-in replacement for a few bucks that takes lower end DA chips and runs several in parallel. I might go for that because that scheme usually lowers noise but also helps correct errors in the digital domain. Cheap to try…

 

[mlucitt]

Jim, what digital source are you converting to analog?

 

[J!m]

The revolutionary Compact Disc.

But, as you see, this supports USB as well, so I could “stream” stuff too.

 

[mlucitt]

Just curious.

 

[J!m]

Water jet finished the rear plate for the input connections. I’ll pick that up today.

Machine shop hasn’t got back to me on the front panel rework yet… I can work it enough to get it working but I’d rather assemble it once.

 

[J!m]

Progress…

 

[VSAT88]

That's awesome. I built a Chinese tube preamp and put it in a cigar box. Lol. I have no idea what I was thinking. It actually looked kinda cool and didn't sound too bad.

 

[VSAT88]

Lol

 

[J!m]

I’ve got an R-core transformer to mount in the opposite corner and possibly a steel wall.

I put a line filter on the inlet, a better Schurter fuse holder and some gold bling Neutrik RCA connectors. The input plate ended up off the back wall a bit- for uh, ventilation. Yeah, ventilation.

I’ll get it all working and send out the front panel for machining when he’s ready for it.

I have already tested it so I know it works. I need to make sure the fancy selector with color coded LEDs works but it should.

 

[J!m]

Once this is done I’ll find the best op amp option and sell it off.

 

[VSAT88]

Think someone will buy it? I couldn't give away the one I built.. HA! Naw for real it looks good to me. Those Neutrik connectors are great I think. Use them on all my interconnect builds.

 

[J!m]

Rean or whatever they call them. Good n cheap.

If I don’t sell it it was a fun project. And I’d sell it cheap because the DAC is at least ten years old now. I’ll see what I can do with it. And I can compare to the Aragon D2A, which is pretty decent, albeit old. Dual mono converters and discrete analogue stage.

 

[VSAT88]

Be willing to bet it sounds better than you might expect I may be crazy, well that point is not debatable but some of the older DAC's like in CD players I have had seem to sound better than some of the newer ones. Yeah, Rean, same stuff I think.

 

[J!m]

Well, I guess we’ll find out soon enough.

I can do a quick comparison of the converters in my $5 JVC DVD player to the DAC. Run them both to my boom box and see if it’s audible. I think the op amp experiments are better left for home with the good headphone amp and good headphones.

 

[Bob Boyer]

That's awesome. I built a Chinese tube preamp and put it in a cigar box. Lol. I have no idea what I was thinking. It actually looked kinda cool and didn't sound too bad.

Eh, as long as there's no sparks...