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Old 30th November 2012, 10:18 AM   #121
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Originally Posted by abraxalito View Post
You must have missed the post where I said it had to sound great on redbook and had to be cost effective - ESS doesn't pass muster on either.
50 dollar part and you're complaining

gives new meaning to tight arsed pom LOL
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Old 30th November 2012, 10:40 AM   #122
qusp is offline qusp  Australia
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Julf: oh hes definitely laughing, check out the special fluffy pink version on his webpage...

@ abraxilito

i'm glad you clarified your position mate, but its certainly a difficult line to walk, diagnostics are totally required to make a good dac IMO and that means numbers, you cant just do it by ear, but nor should the ear be avoided as an instrument.

Quote:
Originally Posted by abraxalito View Post
Sounds not so far from how I view the numbers - as verifying that I didn't make any mistakes in the design. So I should have some idea what the numbers would be in doing the design, then the measurements serve to check I didn't take any wrong turns along the way or mis-wire something at the construction stage.

Ah that's news to me - he actually deceives people with his products then in claiming 24bits in the DAC (or just compatibility with playing 24bit files which isn't unreasonable)? Any evidence for subterfuge that you're alleging? I don't have an issue with the price he's charging - if there are willing customers who are happy to part with their cash, can't see anything dishonest there. In any case contributing to this thread by no means implies you endorse or condone dishonest business practices (if they are indeed ocurring). By citing Mr Altmann I don't thereby rubber stamp his business practices. I just use him as an example of someone who has happy customers on one hand and a marauding band of moaners (who aren't customers) on the other telling customers who are more than happy with the subjective results that they drank the Kool-Aid. That's worthy of ridicule.
its printed on the case.... and it doesnt have an asterix* and yes he has gone on record saying it can drive headphones to the fullest, yet its clear he has little knowledge of what that means... he dismisses many better headphones without having heard them in preference to his ideal headphone, which is a modified $30 Koss headphone. The Koss admittedly punches above its weight (it was the first headphone mod I did like 5 years ago), its not equal to the best available and totally useless for portable listening due to being completely open. which you can see with the pictures in his advertisement page

no Charles, hes not pushing them against his ears because he cant get enough of them, hes pushing them against his ears because its the only way you can get any bass/seal.

if you fully read the specification

Quote:
Supported file type: WAV stereo 16-bit and 24-bit
Supported sample-rates: 44.1 / 48 / 88.2 / 96 / 176.4 and 192 kHz
nothing mentioning its only 16bit there. I dont think you can say it supports a file type it cannot actually use

Quote:
DAC: modified NOS Philips 16-bit R2R with current output
modified hey? perhaps he added the extra 8 bits in there with a mod? I know the Germans are pretty good with technology....

and

Quote:
volume control: 32-bit digital
hmmm. hes only recently included the dac type, didnt always mention the 16bit part, he was very secretive about it, simply saying R2R. I guess after a number of us made a bit of a deal about it he added it.

perhaps he only found out after he got the cases printed? going by that logic my iriver supports 24/192 now that its got rockbox on it....

for me thats equivalent to including the potentially poisonous ingredients on a package for general consumption and then blaming the consumer for not reading the fine print. Certainly there are still a number of people who buy it thinking it plays hires if the user threads are anything to go by. many of them even after theyve been informed seem to think it sounds better 'playing' hi-res....

hard work? its a philips dac with an opamp IV stage and an opamp headphone 'amp' buffer. no doubt both are low power chips given the tiny supply voltage hes got. he makes a big deal about it being 'Burr Brown' very specific, wow quick let me get my cheque-book!

this sounds like a clever idea!

Quote:
On the MAC you can use the free XLD software to load the music on the SDHC card for your *******. I have XLD configured to convert all incoming files (Apple Lossless, Flac, ogg, mp3, etc.) to WAV while copying to the SDHC card.
why didnt we think of that? I can convert all my mp3 to WAV? maybe I should convert it to 24/192WAV while i'm at it?

the funny thing is, I bet thats exactly what some of his customers do. Clearly some enjoy the sound, but I cant get past the smokescreen and the price is absurd, but it makes it seem exclusive and he will make a number of sales because of that.

Click the image to open in full size.

anyway back to the topic, I guess I better go check out your blog, youve certainly set yourself a task =)

Last edited by qusp; 30th November 2012 at 10:45 AM.
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Old 30th November 2012, 10:46 AM   #123
Julf is offline Julf  Europe
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Originally Posted by qusp View Post
check out the special fluffy pink version on his webpage...
All in the name of customer satisfaction... in the best possible taste.
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Old 30th November 2012, 11:44 AM   #124
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Quote:
Originally Posted by Trevor White View Post
50 dollar part and you're complaining
Oooh look yet another strawman. Where do you find them all - is there a field near to your home which produces all the raw material ?
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Old 30th November 2012, 12:04 PM   #125
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Quote:
Originally Posted by qusp View Post
i'm glad you clarified your position mate, but its certainly a difficult line to walk, diagnostics are totally required to make a good dac IMO and that means numbers, you cant just do it by ear, but nor should the ear be avoided as an instrument.
Right - diagnostics is a good way of putting it. Its one of the things I mentioned to you in one of those PMs a couple of weeks back - the idea I had of closing the loop around a DAC+AMP by using an ADC to look at the output of the amp. Having an ADC there counts as a measurement doesn't it?

Well I read that Charles is saying 24bit .wav files can be read and played so I don't see there's a problem given that he clearly identifies that the DAC is 16bit. Incidentally its not R2R coz Philips to my knowledge has never made any. Its current segment.

Quote:
hard work? its a philips dac with an opamp IV stage and an opamp
I was actually thinking of the firmware when I wrote that, not the hardware part. Seems a fair bit of work to write it all in assembler. Has he said he's using an opamp for I/V then? Not very audiophile
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Old 30th November 2012, 12:22 PM   #126
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Originally Posted by abraxalito View Post
Just took some time to watch this - very good, thanks.

I'm surprised they actually went to such extent WRT listening correlation.

A bare bones Sabre sans ASRC would have been nice. (yes I know you can turn
it off).
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Old 30th November 2012, 12:25 PM   #127
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Default 7th order elliptic anti-imaging filter

Here's something one or two of you guys might be interested in - a passive filter designed for NOS DACs. I've read a few reports and agree that NOS sounds a bit rough at the top end - I've wondered if this is due to amps or tweeters creating intermod products with the ultrasonics. So here's a design which I'm currently building to test my hypothesis - a 50dB stop-band passive anti-imaging filter. Ignore the 0.001 resistors, they're just there to see the effects of lossy inductors in running the sim.
Attached Images
File Type: png 7th-elliptic.png (16.0 KB, 83 views)
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Old 30th November 2012, 12:28 PM   #128
Julf is offline Julf  Europe
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Originally Posted by abraxalito View Post
Right - diagnostics is a good way of putting it. Its one of the things I mentioned to you in one of those PMs a couple of weeks back - the idea I had of closing the loop around a DAC+AMP by using an ADC to look at the output of the amp. Having an ADC there counts as a measurement doesn't it?
As part of the feedback loop? Have you looked at the time delay implications?

Quote:
Well I read that Charles is saying 24bit .wav files can be read and played so I don't see there's a problem given that he clearly identifies that the DAC is 16bit.
No, he doesn't. The owner's manual states "It will playback [sic] full resolution CD 44.1 kHz, DAT 48 kHz as well as DVD-A (high resolution) wav files up to 192 kHz with 16 bits as well as 24 bits". Nowhere does it mention that it doesn't actually play them back at anywhere near the "full resolution". It might not technically be fraud, but I would definitely consider it extremely misleading - and slimy. Is that the kind of "engineer" you want to be compared with?

I am sure you will declare this a straw man too.
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Old 30th November 2012, 12:32 PM   #129
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Originally Posted by Julf View Post
As part of the feedback loop? Have you looked at the time delay implications?
No - the key word you seem to have glossed over here is 'diagnostics'. Go back and read again perhaps?

Quote:
No, he doesn't. The owner's manual states "It will playback [sic] full resolution CD 44.1 kHz, DAT 48 kHz as well as DVD-A (high resolution) wav files up to 192 kHz with 16 bits as well as 24 bits". Nowhere does it mention that it doesn't actually play them back at anywhere near the "full resolution".
Not even a PCM1704 does, so the point is moot. Sure it accepts 24bits but the full resolution? Get outa here!

Quote:
It might not technically be fraud, but I would definitely consider it extremely misleading - and slimy. Is that the kind of "engineer" you want to be compared with?
Compare me with Genghis Khan if you like, it wouldn't bother me

<edit> I agree on 2nd reading that the wording you quoted is misleading in respect of 'full resolution'. Black mark Mr Altmann.

Last edited by abraxalito; 30th November 2012 at 12:35 PM.
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Old 30th November 2012, 12:42 PM   #130
Julf is offline Julf  Europe
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Originally Posted by abraxalito View Post
Not even a PCM1704 does, so the point is moot. Sure it accepts 24bits but the full resolution? Get outa here!
OK, so by his (and your) definition even the humblest iPod "plays" high resolution music, as long as that music is converted to a suitable format. Sure. Whatever. At least we know where you stand.

Quote:
Compare me with Genghis Khan if you like, it wouldn't bother me
Only reason I made the comparison was your (much) earlier question that you kept returning to:

Quote:
Originally Posted by abraxalito View Post
You're denying that Charles Altmann and myself are engineers then?
Based on the evidence, I think I would call Charles a con man rather than an engineer. That's why I was wondering if you wanted to be compared to him, that's all. If you prefer Genghis Khan, be my guest, but to me it sounds a bit presumptuous.
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