Musical Fidelity CDT Player

contax · 24th November 2008, 09:57 AM

Hello,

I own a Musical Fidelity CDT Player. It has a signal transformer in the begining of the tube output stage (see enclosed pincture. It's is a cube shielded with a metal sheet). One channel fails.

Temporary I have solved the problem connecting the stage without the transformer. I have inserted one capacitor and one resistor (the signal was too high) in the signal path and the player works again.

I would be interested in the service manual of schematic.

Does anyone know the transformer specifications?. Does anyone know what is the CD mechanism?

Has anyone modified this CD player?

Thanks for your help.

contax · 4th January 2009, 03:32 PM

I think the CD mechanism is a Sanyo SF-90 5/8. Does anyone know any details about the transformer?.

tubenut · 4th January 2009, 06:25 PM

Is it definately a transformer? Would not surprise me if the shield was the hiding place for some op amps.

WRT modding, these units are notoriously quirky, if it works otherwise, I would leave it alone.

contax · 4th January 2009, 09:26 PM

No. I think the shielded "brick" has two transformers inside. It has only three input terminals and three output terminals. One is ground and is common.

My "brick" has one channel faulty. I have tested the other one connecting a sinus wave signal and checked the output with an oscilloscope. The output signal is lower than the input signal.

Maybe the only purpose of the transformer is to supress any DC offset.

Without the transformer and inserting a capacitor in the signal path (before the output stage), the tube oputput stage and the CD work.

molecule3 · 6th January 2009, 07:04 AM

Hello !

I bought this player and I like its vitality, I prefer it to my Arcam CD72.

It's hard to find informations on the Musical Fidelity CDT,
also known as 'Musical Fidelity PAN' (try this in google)

I do not know anything in electronics, but may be this link may interest you, or try contact 'dht' :

http://translate.google.com/translat...istory_state0=

i speak english like a frog, sorry

contax · 9th January 2009, 07:37 AM

This is the power supply schematic published by dht

contax · 9th January 2009, 07:38 AM

and the output stage schematic

contax · 9th January 2009, 07:53 AM

The trafo picture. The DC resistance values are;

R primary = 5.93Kohm
R secondary = 86.40Kohm

The output signal/input signal ratio is aprox 0.7

skibi · 24th January 2009, 11:57 AM

contax,

unfortunately I dont have the service manual. I have only these two schematics posted on audiostereo. Maybe tomant could help you, send him a private message (PW) via audiostereo.
If you want to tweak the CD I suggest you to bypass the trafo and NJM4558 opamp. I can send you a LC7881 datasheet.

dht

liesekarl · 13th February 2010, 01:39 PM

Hi contax!

Do you solved your problem?
I have a Musical Fidelity "PAN" and my one has the same symptoms as yours.
Sometimes the faulty channel works fine.
When i heat up the "brick" it mostly works.

Can you help me?

Best regards

4th January 2009, 06:25 PM	#3
tubenut diyAudio Member Join Date: Nov 2002 Location: South Africa, Jhb	Is it definately a transformer? Would not surprise me if the shield was the hiding place for some op amps. WRT modding, these units are notoriously quirky, if it works otherwise, I would leave it alone. __________________ Guillaume Croak Audio Exploration

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4th January 2009, 09:26 PM	#4
contax diyAudio Member Join Date: Mar 2008	No. I think the shielded "brick" has two transformers inside. It has only three input terminals and three output terminals. One is ground and is common. My "brick" has one channel faulty. I have tested the other one connecting a sinus wave signal and checked the output with an oscilloscope. The output signal is lower than the input signal. Maybe the only purpose of the transformer is to supress any DC offset. Without the transformer and inserting a capacitor in the signal path (before the output stage), the tube oputput stage and the CD work.

6th January 2009, 07:04 AM	#5
molecule3 diyAudio Member Join Date: Dec 2008	Hello ! I bought this player and I like its vitality, I prefer it to my Arcam CD72. It's hard to find informations on the Musical Fidelity CDT, also known as 'Musical Fidelity PAN' (try this in google) I do not know anything in electronics, but may be this link may interest you, or try contact 'dht' : http://translate.google.com/translat...istory_state0= i speak english like a frog, sorry

24th January 2009, 11:57 AM	#9
skibi diyAudio Member Join Date: Jan 2004 Location: Katowice	contax, unfortunately I dont have the service manual. I have only these two schematics posted on audiostereo. Maybe tomant could help you, send him a private message (PW) via audiostereo. If you want to tweak the CD I suggest you to bypass the trafo and NJM4558 opamp. I can send you a LC7881 datasheet. dht

13th February 2010, 01:39 PM	#10
liesekarl diyAudio Member Join Date: Feb 2010	Hi contax! Do you solved your problem? I have a Musical Fidelity "PAN" and my one has the same symptoms as yours. Sometimes the faulty channel works fine. When i heat up the "brick" it mostly works. Can you help me? Best regards

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