Philips CD650 mods

Well I installed my new -15V S Power regulator for the DAC supply last night.

How: As the original reg was hard to get at (Cilla couldn't gnaw through the rear foot) I decided to leave it be. I tapped -30V from the standard supply and ran a wire to the main rat's nest PSU section. I ran a ground wire to the plane, which I scratched into using a fibre pen (wonderful tool). I cut the -15V supply resistor next to the DAC and tagged the new reg's output onto the underside of this area next to the chip. Once I'd checked voltages I fixed a thin heatsink to the S Power, aided by some thermal goop. The heatsink gets quite hot but it's just about ok.

Sound: First impressions were a slight dullness and a darker, more sublime presentation. I believe this can be attributed to a lack of grain and noise in the upper registers. The sound stage is a little better developed and instruments have that bit more texture and smoothness. The treble is better controlled. I'm very happy with that for just over £30 spent.

I now have 6 low noise regs in the CD650 but only a few additional power supplies. I'd like to increase the number but I've ran out of space. It will have to be transplanted onto the plywood slab soon!
 
I'm buying Lee's Pass D1 stage (as a kit) off him now that he's a CD17 fanboi. That will prove interesting, I think it might be somewhat better than the op-amp stage 😉

It will have to run on +-15V but I'm sure it will cope. Later on I may pluck up the courage to adjust the S Powers to run on +-20V or more.

All will be posted here! 😎

Simon
 
Ah yes glad you brought it up, I have been looking without success for a schemo for the Pass D1. Can anyone direct me towards one? I would like to try it in one of my CDB650's

On a different note I picked up a marantz CD63 today for $12 but thats another huge thread.
 
UV101 said:
That pass labs kit should be pretty good Simon. You'll need to seprate those dual Opamps now for sure! I assume you;ll ise it for I/V direct to the output?

There are a few pics of the CD50 here. Nothing too exciting as yet mind!


Good stuff Ian, it looks like you and Cilla have your work cut out.

Yes I'll use it direct, at least to begin with. I need to read up on it a bit more too...


amp-guy said:
Ah yes glad you brought it up, I have been looking without success for a schemo for the Pass D1. Can anyone direct me towards one? I would like to try it in one of my CDB650's

On a different note I picked up a marantz CD63 today for $12 but thats another huge thread.

I have the schematic on my work PC, I'll e-mail it tomorrow.

The CD63 is good with the right mods - clocks and 5V separation in that one.

Simon
 
Mute function

Hi Guys,

This is a bit o/t but I guess if you don't know the answer no-one else will.

I've been playing with on old Philips CD373 (seems pretty similar to the cd50). It's an TDA1541 (non-A) player.

I've removed the daughter board with the mute and output caps,replaced diodes, caps and op-amps.

I was getting some problems with it reading the disc, the disc kept spinning rapidly and then reversing direction and continuing to spin rapidly. I figured out it was a problem with the clock signal from the 7220 chip so I decided to go NOS. I removed the 7220 completely and fed the clock crystal directly into the 7210.

All's well and good and sounding quite nice for a total cost of about £20.

I'm toying with the idea of spending some more money and reclocking it.

But first there's a litle problem that I'd like to solve. Without the 7220 chip in place there's no mute function anymore. Is there someway of restoring this without putting the chip back in?

Thanks for any advice.

Regards

Pete
 
amp-guy said:
Hey Simon is this the one you are getting
http://www.diyaudio.com/forums/showthread.php?postid=616248#post616248
Or is it the version using mosfets?

This is so simple it could be done up like the Burson modules real easy . It could be made with the 2sk389's taken out of the Marantz HDAM instead of two 2SK170's

Looks like mine's with FETs. I was so rushed at work I didn't have time to think about it today, but I'll check this out more tomorrow.

Simon
 
I hope it's ok to post this here. D1 stage attached. I had to remove the PSU page from the PDF to make the file small enough to attach. It was just a very bog-standard PSU anyway.

By my limited understanding of electronics I'd say those two devices are FETs - IRF610. The schematic calls for +-30V but I'm going to use 15 (S Power regulation) and see how it works. I'm also going to leave out the PSU resistors. Output caps will be the Mundorf Supremes I currently use.

Simon
 

Attachments

I don't know how this circuit will respond but in power amps where I have used the IR\Vishay mosfets they like to run hot
the hotter they run the better they sound . Iam referring to biasing here not temperature per se. with half the supply they will not be biased as hard.
But hey try it, like it you will, you can allways mod the supply later.
 
C2 going in tomorrow!

Can't wait! I'll let you all know how I get on.

Been working on the Restek since Lee made me some really cool interconnects. They are pretty special for the price! Attenuated too :angel:

C2 will replace the Trichord Clock 4 and D1. I'm hoping it will be a nice lift. Brent got the new Sanyo SEPC caps in today so i'll be the pilot for the new clock with new caps! I'll report back as soon as I've had a listen.

On a sidenote, anyone got any thoughts on replacing OPA2604 (J-fet opamp) with LME49720's (Bi polar?) Its been commented elsewhere that they might not be that compatible as a swap. They are however in the amp now and sounding pretty good!

Cheers, Ian