CD player modding questions.
Mar 21, 2006 at 5:12 PM Thread Starter Post #1 of 30

Target1

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Howdy all,

I have some basic questions about modding a CD player. I have recently dug up my old Kenwood CD player. Its an oldish model (late 90s, so not that old), and its the CD-404 5 disc changer. First I was wondering if this player could me modded at all. Second, if it can, can I do it? I don't have any experience, but I know some electrical engineers, so I have their expertise/tools to help me. Lastly, is this player even worth modding? I know very little about these things, and would appreciate any help.

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Mar 22, 2006 at 11:59 AM Post #2 of 30

Garbz

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Anything can be modded. It's just a question of how and if it'll be worth it. Without seeing inside pictures we can't say much more. Specifically we want pictures of things close to the sockets on the back.
 
Mar 22, 2006 at 3:17 PM Post #3 of 30

rickcr42

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power supply,power supply,power supply
very_evil_smiley.gif


that is where you will get the most bang for the buck,improving the power supply that feeds everything else.after that it is analog stage then damping the chassis
 
Mar 23, 2006 at 3:57 AM Post #4 of 30

Garbz

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True but don't waste your time putting blackgates or similar stuff in. Much better to change the design slightly. Especialy if it's a switching powersupply.
 
Mar 23, 2006 at 5:01 AM Post #6 of 30

nikongod

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Quote:

Originally Posted by vixr
What were those noises???? It almost sounded like........ engineers hiding tools...


im totally lost on this quote.

assuming the psu is at least decent, MANY cdp's have electrolytic caps between the onboard dac and any onboard amp chips. swapping these electrolytics for appropriately sized film is also AWSOME. even a cheap film is better than the worthless electrolytics that most cd players use everywhere.

you may also like the results of "opamp" rolling for the outputs of the cd player if so equipt.
 
Mar 23, 2006 at 5:12 AM Post #7 of 30

rickcr42

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Quote:

im totally lost on this quote.


I join you in the land of the baffled
confused.gif


Quote:

assuming the psu is at least decent, MANY cdp's have electrolytic caps between the onboard dac and any onboard amp chips.


Quote:

you may also like the results of "opamp" rolling for the outputs of the cd player if so equipt.


many can be improved by totally removing the output stage and using a top quality capacitor to directly couple from the DAC output to the output jacks.You may need to also replace any muting transistors with a proper relay.

In the power section,assuming it is not a basket case requireing a total retrofit increasing the V/A capacity and decreasing the capacitor ESR/series resistance is usually a very audbible improvement when you use a "busy" section of music as the test.Rather than one mass of music blur an improved ps allows you to get some note separation back so you can actually follow individual instrument lines even if that instrument is not the featured one.Very important to me personally.

So lower ps impedance combined with an uncluttered signal path if possible will typoically get the best the built in DAC section has to offer.Reclocking and all the extras is n more of a refining of the improved information retreival and offers less bang for the buck but knowing how DIYers can get,after stage l mods no way you stop before trying stage ll
very_evil_smiley.gif
 
Mar 23, 2006 at 9:19 AM Post #8 of 30

fewtch

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I'm not a DIYer per-se, but have taken quite a few electronics classes (and a little experience)... and I agree with Rick, power supply is probably THE most important thing to improve. I'm using an old Rotel RCD-855 instead of a Toshiba SD-3980 DVD player with 24/192 DAC, almost purely because the Rotel obviously has a much better power supply. Lower noise floor, blacker backgrounds, less congestion, greater transparency... the list of potential improvements is long.
 
Mar 24, 2006 at 4:30 AM Post #9 of 30

vixr

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It was obviously a very weak attempt at levity... He knows engineers with tools? I was suggesting that they would hide the tools, rather than loan them out... humor, its a difficult concept...
 
Mar 24, 2006 at 4:39 AM Post #10 of 30

Xakepa

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Here comes a new one...don't want to hijack the tread, but...

I was told putting in parallel different caps on the signal path is bad. But what about IDENTICAL ones? Two, tree...

I want to multiplicate the capacitane and keep some flexibility of placement.

Thanks.
 
Mar 25, 2006 at 12:29 AM Post #11 of 30

nikongod

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Quote:

Originally Posted by Xakepa
Here comes a new one...don't want to hijack the tread, but...

I was told putting in parallel different caps on the signal path is bad. But what about IDENTICAL ones? Two, tree...

I want to multiplicate the capacitane and keep some flexibility of placement.

Thanks.



i am strongly a believer that caps in the signal path should not be "paralled" unless in exact duplicates of eachother. in the case of the relatively small sizes used in a headphone system this is rarely if ever necesssary.

why do you want to "add up caps" lots of cd players use a big electrolytic somewhere that a smaller film could be used simply because its cheaper. a 10uf electrolytic between the dac and onboard amps can often be replaced by a tiny film cap...
 
Mar 25, 2006 at 1:04 AM Post #12 of 30

Garbz

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The point of paralleling the caps was not to increase the capacitance. It was to bypass a larger eletrolytic with a smaller film. The problem is the difference in propegation between them causes some kind of phasing or distortion or some such thing. Some people sware by it, some hate it. One can only try it.
 
Mar 25, 2006 at 5:52 AM Post #13 of 30

Xakepa

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Quote:

Originally Posted by nikongod
a 10uf electrolytic between the dac and onboard amps can often be replaced by a tiny film cap...


confused.gif


What do you mean by "tiny film cap"? Polyprop or polyester caps are not tiny, and even the largest ones hardy go above 2-3uF. So to have the same capacitance/cut-off freq I'll need 3-4 of those large fellas.
 
Mar 25, 2006 at 7:18 AM Post #14 of 30

Garbz

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possibly that often this cap doesn't actually generate a low-pass filter, although this depends on the circuit. In the Pioneer DV676 it didn't. Infact it wasn't even necessary to begin with. Tiny I guess means it could be replaced with a 0.1uf film or something.
 
Mar 25, 2006 at 6:16 PM Post #15 of 30

rickcr42

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The "bypass the big electrolytic with a small film cap" craze began in a time when most electrolytics dead sucked and there was no alternatives available so it would be comon to see multi-capacitors made up of a single BIG electrolytic,a poly film cap as big as you could get whih usually meant 10uF for the "mid rangew" and finally a tiny film cap of arounf 1uf for the "treble".

It was an option many follwed because the sound was totally different and the conclusion was better and this being DIY audio once a thing is proclaimed better it is "lemmings to the cliff" time.Everyone follows and never questions or does their own thinking (including me once upon a time
rolleyes.gif
)

The basis for this "improvement" was that a large cap is slower than a smaller cap and music is fast and the higher you go in frequency the faster it is so it just MUST be better to use a cap to match the speed of the music in that band of frequencies !

Then there is the other school of thought and the one I follow.One that my ears tells me is the better way.

It came to me after reading about loudspeakers and time delay distortion that a damn lot of effort was going into making each drivers sound reach the human ears at the same time in order to maintain "time" integrity.that is where the upper end sound of the woofer does not come in a tick later than the lower edge of the midrange or the upper edge of the midrange arriving after the lower sounds of the tweeter because this "disjoints" the music instead of presenting it as a single sound as it was recording.

I am reading this and the "hit with a hammer between the eyes" light bul goes off !

while the loudspeaker industry is trying to correct a known fault in systems design we DIY knuckleheads are introducing the very same thing into out electronics with these capacitor "crossovers" where each band of signals is travelling through a capacitor at a different speed depending on its size then mixed togather as a disjointed out of alignment mismash of sounds !

The tiny cap being the fastest means that is the first sound through with the 10uf next and finally the big electrolytic and while we are talking about uS (microseconds) it is heard as a blurring of the notes when the same note is added together (the overlap region of the cap crossover) at the differnt speeds of the caps.

My attitude is better a slight roloff off frequencies that are single cohesive signal than all the notes but off-timing.Damn hard to pick out individual instuments in a busy passage and actually follow what the artist is playing when that note is broken up into three segments and blurred at the crosses.

single cap of the highest quality you can afford at each position is in my opinion the only way to fly.

YMMV
 

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