I've been reading up on DACs a bit lately, after looking around for a DVD player and noticing some had SACD capability.

Looking up SACD comments on the net I found some very detailed technical explanations about how the quality wasn't really that good; frequencies above 8000Hz become underdefined and distorted.

The ubiquitous bitstream/1-bit DAC used in almost all PCDPs and most CD players and related to SACD also doesn't fare too well in the treble definition department.
Multibit DACs are harder to get right (more expensive) but apparently do sound more accurate in practice, though often 18-bits or more are used instead of 16.

Bitstream/1-bit DACs are so popular because they are cheap and the external components needed are cheap and their S/N ratio is quite good.

Anyway, I was quite surprised to come across the Aiwa XP-Z5 MP3/CD player as it was advertised on several (official) sites as having a 16-bit DAC. It's also the only Aiwa PCDP I came across that doesn't use a 1-bit DAC.

The Z5 doesn't seem like much of an MP3 player for the price, it doesn't look particularly nice, doesn't have very many options and apparently cannot even display any text. The MP3 ability almost seems like an afterthought.

This makes me wonder why this particular unit is using a 16-bit DAC. No mention of the amount of oversampling anywhere. Is it a regular DAC or some kind of new system? Does it use a 16-bit DAC because of the way the MP3 audio is handled?
I don't think a 16-bit DAC would be more cost-effective, even if it would perform about the same as a 1-bit DAC.

I'm really curious about how this unit sounds in practice, the treble would probably be more detailed and the soundstage could very well be better from what I've read about DACs. I would like to compare it to my current Philips bitstream PCDP.
The Z5 does have a line-out BTW.

Anyone know any more about this unit or maybe possible other Aiwa or other brand PCDPs that use some kind of multibit DAC?
What kind of DAC do those popular Panasonic PCDPs use?

EDIT: I'm not interested in the MP3 audio, but the regular CD audio, as I can easily hear the quality difference between MP3 and CD.

EDIT: Dread, I just realized I posted this in the wrong part of the forum, if a mod could just move this to the portable part, that would be great.

I agree with your basic observation. I have a ten year-old RCA 2020 that features 18bit DAC. I must say that it's one of my favorite and best sounding players. Now, I realize that there may be other factors. I don't think the headphone output comes close to the Sony D-555, which, come to think of it, also sounds great and has I believe, 16bits.

I prefer either to my Rega Planet! (don't really know what chipset that has).

The thread has been moved as required

Oh, and Aiwa is owned by Sony ~ So I wouldn't hold out too much hope of this being some new wonder-machine that'd dent Sonys own sales...........

Can live in hope though

I just noticed that Sony Singapore is "implied" as the source. For whatever reason (I'm sure not trying to imply ethnic) I've had better-than average experience with Singapore-build electronics. I used to work for an interconnect company and they generally felt Singapore was ahead in some consumer-technology ways.

Of course, this could account for the 16bit chipset. Maybe they have a whole barrel full of them left over.

The romantic in me, though, hopes the unit is better than the others I've owned (Philips MP3 players).

Didn't say whether the Skip-protection is defeatable. Likely not, and, in most cases I've noticed a difference in sound when it's bypassed.

The thing with 1-bit DACs is that their response isn't instantly, so for instance they cannot produce a real square wave. As the frequency of the signal increases, the effective amount of bits to define the signal decreases, the defence being that at higher frequencies you cannot hear the difference anyway. Well apparently you can hear the difference in soundstage and high-frequency instruments like cymbals for instance.
Also lower frequency sounds seem to have a high-frequency element in them, which ofcourse also doesn't exactly sound right.

1-bit DACs use 256x oversampling, instead of 4 or 8x used with 16> bits DACs. They should really use 65536x oversampling for a real 16-bit sound, but that would mean the clock frequency of the DAC would have to be too high to be feasable. SACD has similar problems and most of the signal processing used to make the audio sound smoother is just audio information that is being made-up by the circuitry to fill the gaps. So not all of the 16-bit quality of the original CD is being used.

Indeed skip-protection makes the audio-quality worse. At least on my Philips PCDP, the CD turns twice as fast, which apparently is too fast for proper error-correction and oversampling. It did something very weird with the high pitched sound effect at the beginning of 'Genie in a bottle', which makes it a nice song for testing

Interesting information about Singapore, I indeed got many of the Google hits about the Aiwa at Singapore sites.

Aiwa is Sony, that's right So we might expect this unit to break very easily, even if it would have good sound. I once heard Aiwa is used by Sony as a kind of testbed for products, so who knows
I did read somewhere that some of the less cheap Aiwa PCDPs had good sound and were using an apparently well known DAC of some kind, I haven't been able to find that message again.
I had the most cheap Aiwa PCDP with skip-protection once and the sound was totally aweful.

Thanks for moving the thread!

... might be good news. I just visited a site, hoping to find this unit at a decent price. First, I confirmed that it has a 16bit DAC. Good so far.

Then, If my eyes don t deceive me, there appears to be a button on the middle left top labeled, "EASS", which would mean it is a defeatable feature.

That would solve a major concern.

I meant to add this...

http://www.mypriceelectronics.com/cg...html?E+scstore

I don't know that multibit DACs are always superior to 1-bit...

From http://members.chello.nl/~m.heijlige...%20theory.html
Which is from http://members.chello.nl/~m.heijligers/DAChtml/tech.htm
Which is from this homepage http://members.chello.nl/~m.heijlige...tml/dactop.htm

Quote:

It does seem that there are multiple factors in all this. I try to look at it as part of the fun of the experience, comparing them all. Then we try to apply our antecdotal data collection to form opinions from which to proceed.

Very nice explaination by the way.

You can thank the author of that stuff for that

AFAIK it takes more expensive parts to do a multibit DAC right so for multibit DACs on pcdps... either it was a REALLY high-end model (e.g. the old sonys) or it's probably crap (the aiwa we're talking about?)

Well, I went to a shop today to have a look at it. It's priced at $150, not really very cheap considering the apparent lack of functionality.

I had a look at the manual, the 16-bit DAC was mentioned in the techspecs, but not the amount of oversampling.

The anti-skip system can indeed be turned off, I saw the button, that is indeed great news. Also it runs on two AA batteries. It's quite small but a bit thick, I don't mind, smaller probably means something needs to be sacrificed.

MP3 play is 8 hours with anti-skip, 12 hours without.

The manual also mentioned this unit has a three beam laser, I wonder if this is common for a PCDP, energy consumption-wise and I wonder if this is a good thing error-correction wise.

The manual mentioned some strange MP3 related things, it said 128bits/s would sound best on this device, even though higher bitrates were supported. Then it listed upto 48khz for mpeg1 and upto 22khz for mpeg2, I wonder what that means.
MP3 files have to be named so they appear in the alphabetical order you want to use them in. There's no text displayed, but apparently an album and song number.

One store had the unit for $10 less but was out of stock and I was told there wouldn't be any more coming in.

This player still has me puzzled, option-wise it doesn't seem as good as lower priced mpman, samsung and grundig units. It's also a bit thicker than most. So where did the cost go, is it in the audio quality (here's hoping )

I know multibit DACs are harder to get right, the resistors used need to be really good, or you will have distortions in the waveforms. However, 1-bit DACs have digital conversion, 256x oversampling and still don't handle >8000hz frequencies correctly and not even the lower frequencies. Even the much improved SACD 1-bit converters don't fare well with high frequencies.
So why didn't Aiwa just chuck in a cheap 1-bit converter, they are using 1-bit converters in all their other units. Surely the 16-bit converter wouldn't be a better choice if it sounded much worse at the same price (the DAC might be cheap, but the needed filters aren't).

Interestingly (discussing 1-bit versus multibit in handling high frequencies) one clerk asked for my age, I told him I was 31 and he said at that age I couldn't hear the difference anyway, only before your early twenties, LOL

The clerk at the store selling the Z5 told me I could buy it and swap it for something else if I wasn't happy with it. I asked him if I could try it in the store and he said they usually don't do that, but I might ask on a weekday. I wonder if I could listen well enough in a store if I felt a bit hurried.

I think from the average Joe's perspective, this player is dead in the water, for the average consumer it doesn't offer as many features as lower priced units from other brands. I'm not surprised that other store wasn't getting any more units. So this player might vanish from stores soon, maybe after going on sale, maybe it will just disappear. I'm not too sure about MP3, but for playing CDs the Z5 might just be a very good sounding unit, who knows what those developers in Singapore were up to

EDIT: And I wonder why they would specifically be marketing it as using a 16-bit DAC if it isn't any good...

I just read some reviews about the Aiwa XP-Z3 and they said it sounded really great, there were no noticable problems at all at rates over 128kbit/s. It's a different device though with a text displaying remote, much longer battery life (might mean worse audio) and 1-bit DAC.

EDIT: More news as it breaks

The electronic shock absorption system of Aiwa sounds quite impressive, it's first of all meant to prevent skipping and then to fix it if it does happen (which means the amount of skipping is also less with eass turned off). Apparently it uses a variable disc speed instead of a fixed 2x speed. More interestingly, you can apparently select 12 seconds instead of 48 seconds, in which case you will have anti-skip without audio degradation!

Three-beam versus single-beam laser doesn't seem to make that much of a difference in real life. The two extra beams track the audio track on the CD to see if the reading beam is positioned and focussed correctly.

(part of) The 16-bit DAC accuracy problem was apparently solved by Sony a long time ago already, by using a different type of conversion described here:
http://home.mira.net/~gnb/mac-cdis/cd7.html

"The 16-bit net D-to-A resolution is accomplished by the oversampling, noise-shaping and postfiltering process. "

(this is about 1-bit conversion), this is what I meant when I said that much of the detail in 1-bit conversion is being made up by oversampling etc. For a sine wave, this should work perfectly well, as it's so predictable, for something like a cymbal with unpredictable high frequencies it will work a lot less effectively and 1-bit DACs cannot keep up with the fast changing signal. Basically oversampling etc. is smoothing out the signal, which doesn't really add any detail.

EDIT: (somebody stop me )

I found out the z5 is actually $95 in the US, at etronics for instance.

I also found another multibit DAC MP3 PCDP, two actually, the Grundig Mystixx CDP 9100 SPCD and the 9200 version.
They use an 8-bit DAC with 2x oversampling, which could still yield real 16-bits of audio definition when used twice in serial, which is probably what they are doing. Though I'm not sure if 2x oversampling means half the information is being made up, I think it should mean it operates at twice the speed, making it a real 16-bit converter.

I also found out that 'Genie in a bottle' is the perfect song for testing a DAC The high pitched soundeffect at the beginning (the first one) should sound perfectly smooth, it does on my PC where my CD-ROM drive is connected digitally to my audio card (SBLive1024, not the best audio, but anyway). On my Philips 1-bit PDCP this high pitched sound sounds quite distorted, especially with anti-skip turned on.

I've bought the XP-Z5 earlier this year, because I was curious about the quality of the 16-bit-dac, too. The results didn't meet my expectations, though (see the thread "Question about an MP3-CD player" for more...). But maybe the Grundig 9100 would be worth a try - I think it shares the output circuits with the CDP41xx-series, which I like. Whereas the 9200 only comes with significantly reduced headphone out (2x 5 instead of 2x 15 mW!). The 9100 was rated fairly high on several German audio mags, by the way.

Greetings from Munich!

Manfred / lini

That's pretty strange, so the headphone output on the Z5 sounds really good and the line-out sounds pretty bad.
Seems like they somehow managed to mess up the line-out then

How well does the Z5 handle high frequencies? Could you tell me how well it handles hihats/cymbals and sybilance for instance?

I've read mostly positive comments about the sound quality of the Grundig 9100, though I read one comment which said the sound was muffled and one comment which said that there was a bit of noise while the unit was paused.

I wonder how good the iRiver iMP-400 is at playing CDDA, as so many people are raving about it's audio quality. I couldn't find any information about what kind of DAC it uses.

Well, I went for a Sony d-25s

I was surprised they were still available at eBay, they must have found a lot of those things.

I bought one with 'buy it now' for $45, only to discover there are $40 ones as well, DOH! I wonder why there's a price difference.

International service charge is $15 on top of $15.50 shipping, making the total $75.50 ! WOA! This thing better work.

I wonder if I shouldn't just order a backup one, maybe it wouldn't make a lot of difference in shipping and maybe there wouldn't be an extra fee... I would have a better chance of one of them working properly.... I've just now mailed that question to them...

Anyway, this thing looks absolutely gorgeous!!! All metal with a really cool color and amber backlight even. I already really like 80's design in handheld games for instance, but this one really tops them all. It just might be the best looking PCDP I've seen.

And ofcourse the sound is supposed to be really sweet, with a 16-bit DAC (or two hopefully)

Shame about the short battery life, I'll probably just get an AA battery holder for 6 or 8 NiMH batteries. I even have a battery pack for my Atari Lynx that uses 6 of those really large batteries (what are they called, D-size or something?), maybe that would work as well

For the rest I already have a stabilized variable mains adapter, so that should work just fine with it.

I sent a picture of the d-25s to a friend of mine and he immediately wanted one as well Though after I told him all the drawbacks, he wasn't totally sure anymore (especially with the $30.50 extra costs on top of the price).

If this thing works, I think it's a much better deal than any $75 PCDP I could buy in the shop right now.

Thanks to Russ for the heads-up for this amazing device and my wallet says hi

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The best sound portable CD-player must be AIWA XP-7.

Once I won a AIWA xp-77 (equipped with remote, not as good as xp-7 but is also a legend aiwa). it sound really sweet and warm, you can use it to listen some pop/vocal, but never try Classical.