Tda1541a Nos-usb-dac

[dsavitsk]

Don't know if anyone else has done this yet, so I thought I'd post a picture. There is space for an async reclocker, but I didn't hook it up yet. otherwise, schematic is what you might expect: PCM2707 -> TDA1541A -> Passive I/V -> AD8620. Size is 3.5" x 2.8". Decoupling caps are BG 0.1uF NX. The other 6 are under the board. Sound is pretty good, better than my own TDA1543 based NOS-USB-DAC.

[danb1974]

How's the sound compared to the pcm2707 output?

[dsavitsk]

Originally posted by danb1974
How's the sound compared to the pcm2707 output?

Much better. No comparison, really. I don't think the Vout on the pcm270* or pcm290* sound that good in the first place, but the tda1541a in a nos setup is really quite pleasing.

[Terry Demol]

Originally posted by dsavitsk
Don't know if anyone else has done this yet, so I thought I'd post a picture. There is space for an async reclocker, but I didn't hook it up yet. otherwise, schematic is what you might expect: PCM2707 -> TDA1541A -> Passive I/V -> AD8620. Size is 3.5" x 2.8". Decoupling caps are BG 0.1uF NX. The other 6 are under the board. Sound is pretty good, better than my own TDA1543 based NOS-USB-DAC.

hi dsavitski

Well done.

What is the clocking arangement for usb into PCM2707 and how
jitter prone is it.

I haven't looked deeply into usb dac's but am definately interested
in building one for personal use (PC sound).

Cheers,

Terry

[Extreme_Boky]

Nice work dsavitsk, well done! Web site looks nice as well.

Extreme_Boky

[dsavitsk]

Originally posted by Terry Demol
What is the clocking arangement for usb into PCM2707 and how
jitter prone is it.

Well, there are 2 clocks. One is the async reclocking, which I have not tried yet, so I don't know. I just copied Yeo's schematic. http://diyparadise.com/asynchreclocker.html

For the pCM2707's clock, I just used a standard crystal. I know some people (like the DDDAC) use a high quality oscillator, but the PCM2707's datasheet seems to suggest that this isn't the best thing to do. Because there is no way to turn off the internal oscillator, it seems that all you can do is make it worse. I have not taken measurements or done any comparisons, so I don't know what the right answer is. It is worth investigating, though.

Originally posted by Extreme_Boky
Nice work dsavitsk, well done! Web site looks nice as well.

Thanks

[Spasticteapot]

That's a pretty nice DAC. How much did it cost you to build?
Also, is that an Atmel microcontroller I see?

[dsavitsk]

Originally posted by Spasticteapot
That's a pretty nice DAC. How much did it cost you to build?

Thanks. I think in the $120 range.

Originally posted by Spasticteapot
Also, is that an Atmel microcontroller I see?

Hmmm. Not sure what you are looking at, but no. No microcontroller. I suppose I should post a schematic. There's a messy one at http://www.ecp.cc/images/1541-NOS-USB-DACL.GIF (though I used an AD8620 for the opamp and didn't populate the output filter)

[ezkcdude]

If the following question sounds dumb, please excuse me, in advance. Is it possible to use an ASRC, like the AD1896, in between the PCM2707 and TDA1541, but with bypassing the sample rate conversion in the AD1896? The point would be to use the ASRC only to minimize jitter. I understand the whole idea of a NOS DAC is to avoid filtering/oversampling, so obviously, if the AD1896 filtering cannot be bypassed, this wouldn't make any sense. I've downloaded the spec sheet for the AD1896, but I only gave it a quick lookover. I thought I'd ask first, before wasting too much time on the idea. Thanks! Oh, nice DAC by the way.

[Zodiac]

Hi

I've made a usb dac with the tda1541

see here:

http://www.diyaudio.com/forums/showt...682#post851682

I've since implemented a 12mhz tent clock for the pcm2706 powered off a jung type reg, to be honest I didn't notice that much of a change

It's better than my Discmaster / Benchmark combination and the ease of use definitely wins hands down