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Old 21st January 2004, 07:46 PM   #1
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Default Different sounds from different transports ?


sorry this is a long story...

Today I got an old Philips CD650, broken loading mechanism, but works with some tricks.

Bought it on a city crap yard for 8$ (they have a kind of shop) to get a normal TDA1541A without S1.

I am a little bit afraid for my S1 and like to test the DAC with a cheap chip first.

Unfortunately there is the 1541 without A inside...

Now I listened to that player with headphones and immediately I had the feeling that the sound is more lively and got more energy, rythm and speed, compared to the Technics SL-P770 that I use because of the nice search wheel...

Seems the TdA 1541 even without A beats the Technics, I think 4 x PCM61 or whatever.

__________________________________________________ ____________

Back in time:

I had a CD304 for more than 10 years and was very satisfied.

Did a comparison to Denon DCD685 and preferred that Philips.

This time I used the analog input of my Ultra Curve and the Philips was better via headphones plugged in the CDPs and was better via speakers.

That was even noticeable with A/D and D/A from Ultra Curve.

So I was thinking the Philips DAC was better than the Denon.

__________________________________________________ _____________

Ok, now I connected the Phillips to the SPDIF of my Ultra Curve, and again the sound was so much better.

Hey, that's the same D/A from the Ultra Curve of which lot of people think it is crap.

The Technics sound via headphones is the same like via Ultra Curve DAC / speakers.

And the same for the Philips.

So I am very sure that it is the transport. And it was the transport when I compared the CD304 to the Denon.

I was not 100% satisfied with my sound for the past year and I believe that happened when I swapped Philips and Technics.

But how to realize that when parallel modifying speakers all the time...

Now my question is:

Is it the mechanical transport that makes the difference or is it some signal conditioning / error correction that is possibly better in the Philips ?

In the CD650 there is a CDM2/29 and in the CD304 there is another swing arm transport made of geyish aluminum. Not marked as any CDM.

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Old 21st January 2004, 08:22 PM   #2
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Transport from CD304/mkII
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File Type: jpg cdm.jpg (91.0 KB, 514 views)
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Old 21st January 2004, 08:28 PM   #3
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You seriously never suspected transports make a big difference? Never heard of jitter?
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Old 21st January 2004, 08:36 PM   #4
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Originally posted by analog_sa
You seriously never suspected transports make a big difference? Never heard of jitter?
Where is the suicide smilie ?

Ok, is it the mechanic or the electronic ?

Also when I compared the Philips to the Denon, I listened to pink noise from CD via headphones.

Philips: It came directly from the middle of my head.

Denon: Left and right seemed to be a little bit out of phase, it was not possible to locate 100%.
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Old 21st January 2004, 09:08 PM   #5
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Ok, is it the mechanic or the electronic ?
First of all i don't know **** about digital but of course it's both mechanical and electrical. The electrical part is easier to understand as it involves a clock in order to create the spdif and drivers and both are problematic. Apparently using a normal cd player instead of a dedicated transport is not such agreat idea as the spdif part is commonly an afterthought.

Why would the mechanics be important? I'm really not so sure; the error correction circuits may not be able to fix all errors if the mechanics are very poor but that's probably not the full answer. Very possibly it again has to do with jitter, maybe PS induced from the servo system.

You'll certainly get some more sensible answers as well - i only have a cd player in the car
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Old 21st January 2004, 09:12 PM   #6
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Default in jitter we trust

Am I a jitter junky now ?
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Old 22nd January 2004, 08:54 AM   #7
EDUM is offline EDUM  Netherlands
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Hello Bernard,

Interesting isn't it? For your information the cdm used in your CD 304 mkII is a CDM1. As you can read in other threads defenitely my favorite.

You do hear differences. As you are interested to know what causes the audible differences it is important to very carefully sort out the differences between players. Before jumping on a conclusion think it over again. CD audio is full of surprises!

The CDM1 was made in a time that all the limits in designing a player where not fully known. So from production perspective you want to be save. Lateron as more knowledge was gained costprice becomes more and more important (cdm2, 4 etc.). So this cdm1 is a bit overdimensioned.

Keep in mind that a cd player is supposed to play all discs on the market including that disc with all wobbely, scratched, eccentic artifacts combined on that one disc.

There can be many reasons why a particular disc behaves differently on different players. If that behaviour is just to much for the system tollerances of a part of that player, the end result can be audible differences.

There are some tests you can do. Check the HF from the cdm on an oscilloscope. Is it clean? or noisy? Is it very disc speed modulated? How large is the I3 (highest freq) signal compared to I11(Lowest freq.)? How is it positioned?

If you can read error flags. you can see if the data is intact or error correction or interpolation is used.

Use a Philips 5A testdisc (fingerprints, scratches, dirt) and your scope (!) to see/hear audible differences.

I am still not mentioning the analog audio part, powersupply quality of used parts etc, etc!

So a lot of work to do if you realy want to find out what causes audible differences. As I mentioned CD audio is full of surprises!

Success! and have fun!

The vast number of parameters involved in human hearing make imperfect designs certain.
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Old 23rd January 2004, 07:23 AM   #8
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I made experiment few years ago, and connect AD1893/cs4390 dac with I2s to pioneer laserdisk and to pioneer cd-player. Laserdisk was more detailed and not so dynamic. Now I have laserdisk with non-os r-2r converter and it shows same difference when comparing to philips cd player. So sonic signature of transport stays. I blamed jitter and error corection, but I guess, that is not hole truth.

Good luck,

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