Marantz CD63 & CD67 mods list

[SimontY]

Originally posted by poynton


Hi.

I am half way through modding the HF section in my '63.
The main problem here is the +5v supply. It's fed serially of the same +5v as the uP (MN187164 - QF01 ) and so will be picking up LOADS of hash !! I am cutting the feed and wiring direct to the 5v supply via screened cable. I have also fed the HF Transistors Q501/502 via screened cable for the same reason. The HF signal is now via screen cable from the HF pcb to R501. The original tracks have been isolated and grounded. The final stage is now underway. I have literally just returned from a shopping trip with some thin brass sheet to fabricate a screening 'box' around the HF board itself.

Andy

I need to see pictures please Andy!

[poynton]

Originally posted by tms2000
hi, in my cd63 i have ntice that c801 and c802 is missing , i like to put some caps there, can i use blackgate nx 0.1mf 50v

Hi.

I wouldn't bother.

If you haven't already done so, changing the diodes will have a greater effect.

Andy

[poynton]

Originally posted by SimontY


I need to see pictures please Andy!

When I've finished - Have patience !!!!

Andy

[SimontY]

Originally posted by poynton


When I've finished - Have patience !!!!

Andy

Why of course, please forgive me

It's just the thought of brass being bought especially is quite exciting, for some reason! And I wanna see that coax!

[tms2000]

Originally posted by poynton


Hi.

I wouldn't bother.

If you haven't already done so, changing the diodes will have a greater effect.

Andy

hi Andy,ihave change diode to schoky and most of the caps to blackgate, i know nothing about electronic just simple one to one changing of parts will like to know if it is safe and any benefit to the sound

[poynton]

Originally posted by SimontY


I need to see pictures please Andy!

Almost finished but not yet installed.
The screens were made from thin sheet brass from the local model shop. Stiffer sheet would be neater but this thin sheet can be cut with a pair of scissors.
I used hot glue to fix them making sure they are well supported all over to prevent any shorts - there should be about 1mm clearance. The meter did not show any shorts!
Still to do prior to installation is a bond to earth. I do not think where to earth is important - the screens carry no current so earth loops should not be a problem. I also wany to glue a small piece of screen to the chassis rail to cover the HF transistors
Similarly, the coax screens are grounded at one end only. The ground connection to the HF board was not touched. The coax is RG???, minature 50ohm coax silver 7x? plus silver plated screen, teflon/teflon insulated (bought of EBAY - cheap. Maplin used to sell the same stuff at 3x the price!)
I had to 'trim' the chassis rails as the coax fouled slightly - re-routing would solve the problem but I had already glued them down!

Remnants of the brass will be used to make a screen round/over Q501/502

[poynton]

more

[poynton]

PCB layout

[SimontY]

mmm, tasty!

Thanks for sharing

A question - why brass and not copper? It may sound stupid (beginner here), but wouldn't copper shield RF better?

Looks like a very nice job. I look forward to your report of sonic improvements, if any.

[poynton]

Originally posted by SimontY
............why brass and not copper? .............

HI, Iwas just going to explain but you beat me to it !

My local model shop sells 3 different thicknesses of brass but only 1 of copper - 1.5mm! Cutting is the problem. Cost is another factor - the copper sheet is 5 times the price and the waste factor is high!

.............. wouldn't copper shield RF better? .............

I don't know! Most commercial screens are brass or tin. What are the HDAM screens made of?

I will be using the thicker brass for a screen to the front panel as I may hang some PSU bits on it.

Andt