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Question about regulator of Philips CD104

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Posted on January 28, 2017 at 01:21:03
Tube747
Audiophile

Posts: 419
Joined: May 11, 2004
 Hello!
Other than 7815, what else the Philips CD104 uses in the power supply as regulator purpose?

I want to upgrade those regulators to Dexa replacements.

Many thanks!



 

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RE: Question about regulator of Philips CD104, posted on January 28, 2017 at 02:37:29
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
 Hi,

The service manual is on-line and you can easily find it.

I am unsure changing the regulator chips is the biggest win in this CDP (and others of similar vintage).

A kep problem is the Digital Filter which creates truly massive amounts of noise on many power supplies, at frequencies that regulates are not effective.

Another problem is an inadequate design of the analogue stage, which exposes a "slow" op-amp to very fast edge rates - a recipe for creating transient intermodulation.

This sort of problem can be resolved by changing the circuit or using faster speed Op-Amp's.

I suspect replacing all electrolytic capacitors (they will have aged well past their useful life), cleaning up the power supplies connected to the Digital Filter using suitable means (in my books a few kuF of Os-Cons and serious Chokes) plus using better suited Op-Amp's (or other circuitry - just check old Audio Amateur etc. issues covering mods to these CDP's) will produce a much better CDP than using fancy regulators and clocks, without fixing fundamental issues.

Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: Question about regulator of Philips CD104, posted on January 28, 2017 at 07:29:49
Roseval
Audiophile

Posts: 1846
Joined: March 31, 2008
 An example (caps, op-amps)
The Well Tempered Computer

 

RE: Question about regulator of Philips CD104, posted on January 30, 2017 at 05:29:26
Tube747
Audiophile

Posts: 419
Joined: May 11, 2004
 The unit has some 1500uf and 3300uf capcitor in the power supply, do you think I can replace those caps with BHC T-network (4 poles) caps?

Thanks!

 

RE: Question about regulator of Philips CD104, posted on January 30, 2017 at 16:03:46
fantja
Audiophile

Posts: 15519
Location: Alabama
Joined: September 11, 2010
 Tube747

post some pics of your project!

 

RE: Question about regulator of Philips CD104, posted on February 6, 2017 at 10:47:22
Crazy Dave
Audiophile

Posts: 14371
Location: East Coast
Joined: October 4, 2001
 Hi Thorsten,

I have a Mission working DAD7000, which sounds smooth but very veiled to me, compared to my modest NAD C525 BEE and various Sony ES machines from the 90's in my collection. When I changed the belt so that the door would work, I was impressed at how well built this player is. It had occurred to me that a replacement of the electrolytic capacitors could really help. After all, the reputation is that this player should sound good. I am also suspicious of the mysterious box that mission put before the output jack, that I suspect is there to smooth the sound, but could be adding some veiling.

Lampizator suggests Burr Brown OPA2604 for the Op-Amp. Do you thing that it would be suitable?

Dave

 

RE: Question about regulator of Philips CD104, posted on February 6, 2017 at 16:48:55
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
 Hi,

Never worked on a Mission, but not many comments here, but a full recap does tend to help a lot on older gear. Full Recap here meaning replacing each and every electrolytic cap in sight with modern alternatives.

I would not use the OPA2604 these days. But I really don't want to get into "Op-Amp du jour" debates. I still think the correct choice for CDP are low noise, high speed Video Op-Amp's.

Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

Thanks! (nt), posted on February 6, 2017 at 20:10:13
Crazy Dave
Audiophile

Posts: 14371
Location: East Coast
Joined: October 4, 2001

 

RE: Thanks! (nt), posted on February 7, 2017 at 04:55:43
fantja
Audiophile

Posts: 15519
Location: Alabama
Joined: September 11, 2010
 Keep me posted and your project -Crazy Dave

 

RE: Thanks! (nt), posted on February 7, 2017 at 08:49:43
Crazy Dave
Audiophile

Posts: 14371
Location: East Coast
Joined: October 4, 2001
 Will do!

Dave

 

RE: Thanks! (nt), posted on February 7, 2017 at 08:51:25
Crazy Dave
Audiophile

Posts: 14371
Location: East Coast
Joined: October 4, 2001
 Worst case scenario it will be great solder practice!

Dave

 

RE: Thanks! (nt), posted on February 7, 2017 at 13:01:27
fantja
Audiophile

Posts: 15519
Location: Alabama
Joined: September 11, 2010
 We need more "modders" cd players- Dave.
Have fun!

 

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