So here is some commentary and RMAA measures of the Sansa Zip ... and the Creative Zen which I bought a while ago based on CNET and Amazon rave reviews:
http://www.cnet.com/products/creative-zen/These are mini SS type MP3 players which have been heard by quite a few and may be used as reference for what to expect when looking at measurements for that same reason... Which is why I think NwGuy started his blog with the Clip+ and the iPhone. Well that and to take a dump on RMAA. The dScope is not cheap after all, and once the purchase is done you better believe that the dScope is awesome. Make a blog entry if that's what it takes... *sigh* and then came AMB, and HC, and HF, and the O2, and the ODAC and so forth...
Can't really complain too much, cuz I actually read Nw's speech on the Clip+. And given that Zip and Clip+ seem to share audio HW I decided to put like $30 where my mouth was to buy one, in part based on his recommends... and it's good!
This thing, after Rockbox, sounds fantastic for the price. I sometimes use it as a car player by either plugging the usb port or the headphone out to the car Aux in... and I think it beats the built in CD player. A fantastic little gadget that any cheap audio-enthusiast should have.
So anyhow, quite a few folks and their mom's have made measures of the Zip and Clip+, so what gives... here are a few more. The following are to 32 ohms and at 0.421 Vrms (according to my BK Precision 2709B purchased per
Nate Maher's recommends)
Frequency Response
Like Nw said, pretty awesome, and maybe some Class D thing w/o caps.
THD
Nw measured this on the Clip at 0.186 Vrms instead of his usual 0.4 Vrms... which is fine. I think he came up with 0.05% into 15 ohms. Well I did it at 0.421 into 32 ohms and got 0.025%. The load is indeed easier so that might explain why I got less even when voltage was higher. Spectrums are kind of similar.
Output ImpedanceNw looses his mind about this one... and RMAA does not duit!!! But fear not. My $100 bucks multimeter can... He said 1 ohm, I got 0.61 ohms.
Maximum OutputYup, RMAA cannot measure that one either, cuz PC's usually don't come with quality integrated multimeters. So Nw determined that max output was somewhere around 0.489 Vrms, and Clip+ didn't clip! Well, using Rockbox it turns out that one can go +6 dB which measures 0.845 Vrms, and Zip still doesn't clip.
I get about 0.029% distortion, instead of Nw's 0.06356(2681258158)%, proly cuz I used 32 ohms load instead of 15 ohms.
IMD distortionSo he gets 0.03% (0.180 Vrms into 15 ohms) which he decides is inaudible based on his tape hiss speech (which I dunno if true). I get 0.038% (0.421 Vrms into 32 ohms). And yes plots look kinda similar.
So, didn't do DAC linearity or Jitter spectrum. Maybe next time. Thinking maybe REW for that one. Dunno.
Nw did some RMAA stuff w 0.180 Vrms into 15 ohms which does look different from his dScope st
uff. I may put together a 15 ohms load and do this again to check the IMD numbers he got. Maybe something is up with RMAA... or Nw's Benchmark ADC1.
*CREATIVE ZEN*
Now comes the Creative Zen as an example of what can go wrong with some DAPs. The maximum voltage I could get out of this DAP was 0.048 Vrms. One is going to need some very efficient cans. I had to do some trickery to get RMAA to even detect it.
Impedance? like 0.94 ohms.
Frequency Response (32 ohm load)
... Yes, it sounds like that. Maybe it's got some caps at the output or something.
Distortion is hard to characterize given that at 0.048 Vrms it may be bellow the noise floor. Hard to judge by the plots.
So summary: Clip+/Zip rocks, Creative Zen (discontinued) SUCKS! RMAA also rocks. Disclaimer: Used my $150 (or less depending on sales and Black Friday conditions) 2i2 as interface + $100 multimeter, so proly all that I did is wrong. Also, no animals were harmed in the testing.
