DIYHiFi.org

------------------------------------------------------------------------------------

I can swap between the DF1704 and PM100 in my Assemblage DAC 3 and often prefer the DF1704. The PM200 in the successor model DAC3.1 sounds distinctly inferior. I cannot change chips though and this may be also due to a different narrower PLL.

That's right, to buy the chips you needed to sign (and pay) a $$$$ HDCD license.
Anyway, I'm still hoping to find a few, even if I need to buy some broken cdps or dacs for cheap, just to get it.
Sometimes I do this.
I once payed 10€ for a broken Sony minidisc player.
Well, the TORX176 and TOTX176 optical transmitter and receiver it had more than justified that money. The PSU trafo is also in use to charge some batteries, it had just the right voltage I needed.
And plenty of screws.

_________________
Carlos Filipe

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein

Does anyone know of any list of devices that use the PMD100?

[quote="carlosfm"][quote="Glassman"]why do you say no upsampling

I know, and I love it. But what it does is 8x oversampling.
If you consider that exactly the same as upsampling, then whatever.
And the AD1862 is a very good dac too, one of the best IMO.

-----------------------------------------------------------------------------------

Oversampling is not upsampling, although the algorithms(s) may be similar.

With oversampling, you are still feeding lower rate data into your dac and the brick wall filter is still at 44.1k or whatever. With upsampling, you are feeding higher rate data and doubling (or more) the break frequency.

Chip upsamplers that I have heard are notconsistent or good. Software based ones (such as dCS) are much much better and truly improve the sound.

Umm no. This isn't true, or rather makes no sense in comparison with upsampling. If you regard the upsampler plus DAC as a single system it is isomorphic to an oversampled DAC.

My standard internet reference for this is the posting by Max Hauser from 1991 - I keep a copy here for occcasions like this.

http://www.cs.adelaide.edu.au/~francis/ ... mmary.html

Fred,

Oversampling and ?Synchronies Upsampling? perform Exactly the same function.

With Oversampling, (lets say 8 times Oversampling) you feed data into the DAC at 352.8 KHz (for CD), thus your analogue filtering can be much gentler ? this is the main reason behind Oversampling.

The latest ?Fad? for ?Upsampling? is just one of these ?Audio Fashions?, created by the Hi-Fi press in there pure ignorance ? as even the most basic CD players already incorporated ?Upsampling? ? in the form of Oversampling.

Ironically, Upsampling to 176.4 KHz is equivalent of only 4x Oversampling ? where as most CD players and DAC?s already Oversampled (Up-sampled) to double at 8x Oversampling.

Dominic was completely correct in saying that the PMD100 performed ?Upsampling? ? its an Oversampling digital filter ? and normally used in 8x Oversampling mode (44.1 KHz x 8 = 352.8 KHz).

John

_________________
Hi-Fi??? "I may not be a psychiatrist but I know insanity when I see it - what ever happened to the normal old pervert who was content to sniff bicycle seats and collect women's shoes anyway?"

It's interesting to note that Stereophile said in 2000 that there were no conceptual difference in between upsampling and oversampling. Funny also that the two first words of the article are "Charles Hansen". http://stereophile.com/asweseeit/344/

In my view, upsampling is multiplying the original sampling frequency and feeding that to the digital filter.
Of course, the digital filter must accept that, and the PCM100 only does up to 48khz.
What the digital filter (most are integrated into dac chips now) does with that, what it mutiplies with, what clock it needs, that's another story.
In the end, it feeds the dac always at the same rate, no?

_________________
Carlos Filipe

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein

Fred,

Oversampling and ?Synchronies Upsampling? perform Exactly the same function.

With Oversampling, (lets say 8 times Oversampling) you feed data into the DAC at 352.8 KHz (for CD), thus your analogue filtering can be much gentler ? this is the main reason behind Oversampling.

-----------------------------------------------------------------------------------
John

Yes but as Carlos notes in post after yours, it is what the digital filter will accept and not what the dac will take.

I have never been comfortable with 16/44.1 CD and it has nothing to do with the hifi press but what my ear hears.


Fred

come on fred, please learn how to quote properly....

----------------------- crap is not really a solution.

Does anyone know how dCS implemented their software solution(not the details, altho those would be great to have) and/or what hardware it runs on?

John,

What does cause 222Hz components? They are constant in your graphs showing self powered 2706 but are absent when receiver is powered from the Vbus. I?ve zoomed my graphs and can?t find anything like that either (though, BTW, now zooming I?ve discovered that I have relatively strong 15Hz component).

Pedja

Pedga,

Yes, I also found some really LF stuff, will perform a Narrow span sweep to resolve these better.

Not sure what causes the 222Hz stuff - will try differant computers...

Just performing longer sweeps, will post once completed,

John

_________________
Hi-Fi??? "I may not be a psychiatrist but I know insanity when I see it - what ever happened to the normal old pervert who was content to sniff bicycle seats and collect women's shoes anyway?"

------------------------------------------------------------------------------------

You can get quite a useful glimpse by going to dcsltd.co.uk. Look up the technical section and look at the 974 manual. The software is their own and programmed into a ROM. Their dac is the ringdac based not on 1 bit but 5 bit technology. The hardware cannot be deciphered easilly without a schematic. The digital transmission waveforms in the manual are real, excellent and have been confirmed by myself.

I have been there and as they build, they connect to their own FFT to see what is going on.

The pro stuff is much more resonable than the hifi stuff which is inferior in control function and costs more than double!

Hi!
I cant get work PCM2706/7.
Win 2K cannot recognize USB device, Linux dmesg shows some USB addressing error 71.
Voltages are Vbus, Vccp, Vdd 3.3V, HOST 5V, XTO 3.3V??, suspend some millivolts??, I2S pins 0V.
Tried another crystal. Nothing.
So, could anyone check my schematics below, maybe there are some mistakes.