2007 Micro Amps and Micro DACs - Page 7 - Head-Fi: Covering Headphones, Earphones and Portable Audio

TheSloth · 08-02-2007, 08:43 PM

Quote:

Originally Posted by John_H88

I'm really interested in the new Portable Micro with the DAC option. From a review of this thread it seems the DAC is essentially the same as the Micro DAC, so does that mean it has both the PCM2902 and the CS4398 and thus has 24-bit capability? This should give it a theoretical advantage over other portable amp/dac combo's like the Move and the NKK01se that are 16-bit. I take it this is now a preorder item as its available now but not shipping until Sept/Oct?

The BB chip (a different model number to the one you quote, I believe) takes care of the USB-S/PDIF conversion at up to 16 bit/48kHz. The native S/PDIF inputs to the 4398 can lock at up to 24 bit/96kHz.

John_H88 · 08-02-2007, 09:04 PM

Thanks, I pulled the PCM2902 model number from their website specs for the Micro DAC so thought that was the one. Anyway, I am now a little confused how the DAC section works. If the USB-S/PDIF conversion downsamples a 24-bit/96kHz source to 16-bit/48kHz, and passes that signal on to the CS4398 (I guess upsampling to 24-bit/96 kHz?), is it right to say the DAC has 24-bit/96kHz resolution? Its obviously not the same thing as the signal staying at 24-bit/96kHz all the way through to analog conversion. Am I looking at this correctly?

TheSloth · 08-02-2007, 10:05 PM

Quote:

Originally Posted by John_H88

Thanks, I pulled the PCM2902 model number from their website specs for the Micro DAC so thought that was the one. Anyway, I am now a little confused how the DAC section works. If the USB-S/PDIF conversion downsamples a 24-bit/96kHz source to 16-bit/48kHz, and passes that signal on to the CS4398 (I guess upsampling to 24-bit/96 kHz?), is it right to say the DAC has 24-bit/96kHz resolution? Its obviously not the same thing as the signal staying at 24-bit/96kHz all the way through to analog conversion. Am I looking at this correctly?

No, the downsampling is earlier in the chain. The USB interface in the PCM chip doesn't support any input stream higher than 16/48, so the computer will have to downsample to achieve a lock via USB, if it's a computer source. The PCM chip itself doesn't do any resampling - it will simply lock to whatever the source sends, up to and including 16/48. There is also no re/upsampling in the DAC in those models - the DAC will be fed whatever the original input is clocked at.

John_H88 · 08-03-2007, 12:26 AM

Thanks for clarifying that, I get it now. The s/pdif inputs can be resolved at 24-bit but the USB input can not. Are there any USB DAC's that can take 24-bit/96kHz on the USB input?

rumatt · 08-03-2007, 12:41 AM

Quote:

Originally Posted by John_H88

Are there any USB DAC's that can take 24-bit/96kHz on the USB input?

I believe the Benchmark DAC-1 does do 96/24 through USB.

Most do not (example, Headroom Desktop and Stello DA-100 don't).

Tyll Hertsens · 08-03-2007, 01:15 AM

Just dropped in to see if there were any critical questions come up. I'm in the midst of writing the web copy at the moment so that we can put up the pages and start taking pre orders, so it seems nuts to spend the time splaining it here when I could get the stuff up and answer many questions. (Unfortunately that includes gettiung the manuals done--and you won't see those for a while 'cause Ivy actually does most of the work).

Anyway, Sloth, Dude, you rock! Great answers, thanks! I agree that it Tortilla Yeast should just hang on to his unit, or upgrade to the Ultra Micro Amp.

The other thing to clarify is that the pre-amp output is bassically a second headphone jack in parallel with the one on the front.

OK, all together: "AWWWW, that sucks!"

To which I say: "GEEEEZZZ, when are they ever going to get it." Yes, the line out on an iPod is better than the headphone jack. And, yes, usually you'd NEVER want the headphone jack on something to drive a power amp or something. But our amps, and Rays amps, and Justins amps, and Mikhails amps, or any really good headphone amp is NOT your ordinary headphone jack. A good headphone amp makes a great pre-amp because it can drive any load (cables, imput impedance of the power amp) with wonderful authority. So when we lable that jack on the back "Pre-amp" it does function very well as a pre-amp out, but the truth is, you could plug a second headphone in there.

lextek · 08-03-2007, 01:52 AM

If I use my Macbook as a source (it has optical out). Which would be better the USB or Optical? I'm assuming the optical?

lextek · 08-03-2007, 02:42 AM

I guess I'll find out, I just ordered the new Portable Micro w/DAC.

Tyll Hertsens · 08-03-2007, 04:17 AM

Quote:

Originally Posted by lextek

I'm assuming the optical?

Yeah, optical. If you can get it to spit out higher sample rates the Micro Portable will decode 'em.

Just spent a couple days with the Micro Portable and my iRiver iHP140. It's a nice, smooth, responsive machine that's like a Swiss Army Knife for audio. I'd KILL for someone to make an iHP140 clone. I gotta go post in HeadRoom's "You oughta" thread about them making a portable player.

Oh. :blink: That's me.

Torula Yeast · 08-03-2007, 05:50 AM

Quote:

Originally Posted by Tyll Hertsens

Anyway, Sloth, Dude, you rock! Great answers, thanks! I agree that it Tortilla Yeast should just hang on to his unit, or upgrade to the Ultra Micro Amp.

I appreciate Sloth's assessment and your honest confirmation, Tyle. Truth is, I'm enjoying the bejupiter outta my current rig, and will likely savor what it does for my 325i's for many moons to come.

And I don't even mind that you were close-but-no-cigar on my screen name!* :allteeth:

*yes, i know i returned the misspelling favor. heh.