[Xakepa]

Analyzing my home rig, I decided that the bottleneck is the source, so I consider SC upgrade or external DAC. I'm not happy with "digital" sound of EMU0404, and I see no other upgrade in sub-$100 range, and I don't want to spend >100$ on SC when I'll use only sound reproduction capabilities of it, so I'm leaning against DYI DAC.

The field here is not excessively wide, and as I dismissed DDDAC MK2 being too complicated and expensive, I'm trying to collect feedback on Monica and Monica2

-Is it warm/bassy?...or how you'll describe it comparing to mediocre source like modded AV710 or EMU0404?

-Is it possible...and how hard it is to feed TOSLink from AV710 into Monica2

-Could I power Monica2 from unregulated PS?

Thank you.

 

[kdaq]

Quote:

Originally Posted by Xakepa ... The field here is not excessively wide, and as I dismissed DDDAC MK2 being too complicated and expensive, I'm trying to collect feedback on Monica and Monica2 -Is it warm/bassy?...or how you'll describe it comparing to mediocre source like modded AV710 or EMU0404? ...

I'm also curious what would be required to allow Toslink input.

I heard n_maher's Monica2 at the National meet. What a sweet little DAC. It DESTROYS the AV710. I haven't heard an EMU0404, but I would expect more of the same.

Thing is, though, it is quite an 'organic' sound, being Non-OS. Might not be your cup of tea, or might not synergize with the rest of your rig. My listening conditions weren't the best, but I can tell you it is definitely warm. I think of the sound as 'electric' - very vibrant and alive. It drew me in instantly: this is no subtle presentation.

It should be noted, I was running via a PPAv2 amp, which is known for being very bright and forward. The electric vibe might largely be due to how these two melded.

Highly recommended!

 

[Samgotit]

It's possible. Below is how it's done in the DAC AH. It uses the same controller as the Monica II.
IC1 is the optical receiver. JQ1 is a signal relay:
http://www.datasheetcatalog.com/data...2-4.5SNU.shtml

 

[eVITAERC]

It doesn't require much really. All you need is a TOSLink reciever module. IT accepts the optical signal and converts it to electrical ones. Since it operates on S/PDIF as well, no extra conversion is needed.

You do, however, need an extra supply line to the toslink module. Depending on the voltage required by the module you chose, you may have to come up with some other way to tap that.

 

[Xakepa]

Could you pls refer where I can get such a module. 20min googling is not enough.

 

[Garbz]

If you're chasing better sound adding a TOSLINK is very counter productive. It would be better modding the source of RCA or BNC output! Toslink is the worst digital interconnection, just look at the jitter characteristics on any datasheet of TORX and TOTX modules. Caution figures may disturb some viewers.

 

[Xakepa]

Quote:

Originally Posted by Garbz If you're chasing better sound adding a TOSLINK is very counter productive. It would be better modding the source of RCA or BNC output! Toslink is the worst digital interconnection, just look at the jitter characteristics on any datasheet of TORX and TOTX modules. Caution figures may disturb some viewers.

Have no fear.

That's what the Asynch Sample Rate Converter does on the other end - Monica 2 have one

 

[labrat]

Deleted.

 

[Samgotit]

Here is the optical receiver page from digikey:

http://dkc3.digikey.com/PDF/T061/0205.pdf

 

[ble0t]

Quote:

Originally Posted by Xakepa Have no fear. That's what the Asynch Sample Rate Converter does on the other end - Monica 2 have one

That is a very incorrect statement...there is no ASRC in that circuit at all. The Monica 2 attempts to reclock the data asynchronously, which actually adds more jitter.

 

[Xakepa]

Quote:

Originally Posted by Samgotit Here is the optical receiver page from digikey: http://dkc3.digikey.com/PDF/T061/0205.pdf

Thanks, Sam, that looks good.

Quote:

That is a very incorrect statement...there is no ASRC in that circuit at all. The Monica 2 attempts to reclock the data asynchronously, which actually adds more jitter.

...what do you mean by "there's no circuit at all" and "attempts"? The ASRC is CD74ACT374E from the back, or that's what I'm getting looking at the board and reading the description.

 

[00940]

Let's say there is no real ASRC. ASRC means asynchronous sample rate converter/conversion. In the monica, there is an attempt to asynchronously /reclock/ the incoming data.

 

[ble0t]

Google the CD74ACT374...it's just simple Flip-Flop logic. Here's the actual circuit that the Monica 2 employs:

http://www.diyparadise.com/asynchreclocker.html

All this does is reclock the data, which does nothing to actually reduce jitter but instead just introduces more. Read this post (and the associated thread) for more info:

http://www.diyaudio.com/forums/showt...345#post335345

A true ASRC is something along the lines of the AD1896.

EDIT - You're too fast for me 00940

 

[Xakepa]

Quote:

Originally Posted by ble0t Google the CD74ACT374...it's just simple Flip-Flop logic. Here's the actual circuit that the Monica 2 employs: http://www.diyparadise.com/asynchreclocker.html All this does is reclock the data, which does nothing to actually reduce jitter but instead just introduces more. Read this post (and the associated thread) for more info: http://www.diyaudio.com/forums/showt...345#post335345 A true ASRC is something along the lines of the AD1896. EDIT - You're too fast for me 00940

I got the differecne, interesting thread, thank you guys.

The only thing that puzzles me is why Monica-2 and DAC-AH choose CS8412/14 instead of true ASRC...is it much harder to implement?

Thanks.

 

[Garbz]

Quote:

Originally Posted by Xakepa Have no fear. That's what the Asynch Sample Rate Converter does on the other end - Monica 2 have one

That's scarier then a poor input stage. My ears just ran away.

A better circuit wouldn't make a difference. Asynch reclocking simply doesn't work (data clock and reclocking clock out of sync and what not, lotsa info on diyaudio about this). There's no reason to make it perfect or employ a "better" circuit. Personally i prefer a good non-reclocked circuit that does everything to minimise existing line jitter, then have asynch reclocking making a crap design crap in a different way

.

That said async reclocking adds a certain sound signature which some people seem to like, but as far as reducing jitter, no hope asynchronously.