Marantz CD63 & CD67 mods list

[awpagan]

Originally posted by poynton



Or buy a CD63 / 67 and modify it !!!!!

IMO using a cd-p as a transport is a NO-NO !

Either buy a dedicated transport and a good dac

or

Buy a cd-p with a good front end and modify the dac etc.


The spdif out on most cd-ps is a low cost compromise.

Better still, build your own no-compromise cd-p from scratch !

Thats why i got the CD67

but if you have a spare cdprayer sitting around
cheaper to mod and learn
ps learn? the electronics and also what to listen for.

yes cdm-pro2, i2s out, dac? undecided on which dac still.

That's why i also said i2s out

Function control for the transport?
easy to adapt an old cdplayer control panel.

allan

[Luke]

Ray,

thanks for your imformative post. I think maybe I skip the new output stage on the cd6000 and get round to doing this on my cd67, I like easy
Although the solution Thorsten gives seems ok, why cant the gain be upped?
I actually think the cd67 has way more potential than 6000, but its taking me along time to get through this project. Will post some pics when Im done.

seeya arthur

[6h5c]

Originally posted by Luke
Ray,

thanks for your imformative post. I think maybe I skip the new output stage on the cd6000 and get round to doing this on my cd67, I like easy
Although the solution Thorsten gives seems ok, why cant the gain be upped?
I actually think the cd67 has way more potential than 6000, but its taking me along time to get through this project. Will post some pics when Im done.

seeya arthur

Hi Arthur,

Indeed the 67 is much easier. The 6000 has lots of extra silicon on board and a more complicated clock distribution. I think it will sound better in the end too.

Thorsten's circuit works and sounds fine, but the gain of the tube buffer is max. 1x. That's because the lower tube acts as a kathode follower. For a gain >1 you need a different circuit.

Regards,

Ray.

OOPS, did it again.....
I couldn't resist, I bought a CD57 for 25 euro's.....

[awpagan]

Originally posted by 6h5c




Ray.

OOPS, did it again.....
I couldn't resist, I bought a CD57 for 25 euro's.....

for this one a fet output(buffer) stage?

allan

[6h5c]

I think I will try that anyway . I want to replace the two BC550's of the differential stage by the FET's that are originally in the HDAM (2SK369). See how that sounds. The pinning matches, so it's a 1-on-1 swap....

Ray.

[philpoole]

Hi All,

A slight aside...
I've not had the chance to tinker recently, but I was listening the other night, and for quite a while not listened to any CD-Rs.
To my amazement, I noticed that my CD63 now plays all CD-Rs without fault!!!
Beforehand, it would be okay, but it might stop on a track change, especially if you skipped ahead a few tracks.
Now its fine.

Really not sure which mod made the difference, maybe it was a collection. I can't help thinking it was the added weight on the clamp, but that's just a hunch.

Ray,
I dug out Horowitz to reinforce my theory on diff amps. Still can't quite remember the specific benefits of removing the emitter resistors, bar that they are supposedly negligible, but if simulations suggest a difference, then its worth it.
BTW what do you simulate with? I tend to avoid simulation purely because I often design on paper (I sit in front a PC for a living), but there are obvious benefits.

Cheers,
Phil

[awpagan]

Originally posted by 6h5c
I think I will try that anyway . I want to replace the two BC550's of the differential stage by the FET's that are originally in the HDAM (2SK369). See how that sounds. The pinning matches, so it's a 1-on-1 swap....

Ray.

How much balance is useful on the input pair?

i have some 2sk368's and 2sj109'ssitting waiting for something

allan

[6h5c]

Originally posted by philpoole
Ray,
I dug out Horowitz to reinforce my theory on diff amps. Still can't quite remember the specific benefits of removing the emitter resistors, bar that they are supposedly negligible, but if simulations suggest a difference, then its worth it.
BTW what do you simulate with? I tend to avoid simulation purely because I often design on paper (I sit in front a PC for a living), but there are obvious benefits.

Cheers,
Phil

Hi Phil,

Emitter resistors bring thermal stability. As temperature rises, Ube will be lower, so Ic will rise. The drop across Re increases because of the higher Ic, so that will compensate for the lower Ube.
They also provide local feedback, so they can be used to set the amplification of the stage.
I found a good site here.

For simulations I use Micro-Cap 7.0. I do not navigate blindly on it, but it is a very handy tool.

Regards,

ray.

[6h5c]

Originally posted by awpagan
How much balance is useful on the input pair?

i have some 2sk368's and 2sj109'ssitting waiting for something

allan

I wanted the input stage to be as balanced as possible, so for the input stage I matched the resistors and the BC550's Hfe with my transistor tester, but I don't have a tool for FET's. And besides, I only have the four that originally came out of the HDAM .

It cancels the noise that's common in both DAC outputs, so a good balance doesn't hurt.

Ray.

[Fidelity Audio]

Hi dont want to go off topic but I bought some 22000uF Silmics which are very rare for my KI amp.

They have arrived and i'm starting to think they won't fit. LOL