Marantz CD63 & CD67 mods list

[Thomo]

I've only ever used two regs on the decoder of a cd63. I think I used three on the cd67, but that is a different thing altogether as that chip incorporates Servo also.

I have discontinued my CD63, as like Simons, the thing kept going wrong due to having to remove the board with all the extra parts to work on it. (Although I managed to repair it without "professional help", lmao.

I got a great bargain on an old battleship Marantz CD94! This is fairly well modded now, some low-noise regs, full cap replacement, output stage completely re-worked - opamp I/V and discrete output, but has only one extra psu installed so far. I am dumbstruck by how much better it is compared to my cd63.

Cheers, Lee.

ps - I'll get back to those guys about boards very soon

[RCruz]

Originally posted by Thomo


I have discontinued my CD63, as like Simons, the thing kept going wrong due to having to remove the board with all the extra parts to work on it. (Although I managed to repair it without "professional help", lmao.

Hi Lee

Maybe this one is my last mod in the CD53.... I will feed the decoder on it´s psu because I can access it from below without lifting the board out (I left the big hole below the chassis open).

I also have a mains line near the decoder (used for the clock psu) and the TX is small enough to be placed near by.

This will be one of the safest modds I have done.

I had professional help... but all the hand labour was mine

I am taking it easy now.

Regards

Ricardo

[Fidelity Audio]

Originally posted by Thomo


I have discontinued my CD63, as like Simons, the thing kept going wrong due to having to remove the board with all the extra parts to work on it. (Although I managed to repair it without "professional help", lmao.

Cheers, Lee.

ps - I'll get back to those guys about boards very soon

But you got "professional help" on the CD94 LOL

Brent

[Fidelity Audio]

Originally posted by Luke


Ken Ishiwita would be so proud

Nah it's well above his head LOL

Brent

[Fidelity Audio]

Originally posted by RCruz


Hi Lee

Maybe this one is my last mod in the CD53.... I will feed the decoder on it´s psu because I can access it from below without lifting the board out (I left the big hole below the chassis open).

I also have a mains line near the decoder (used for the clock psu) and the TX is small enough to be placed near by.

This will be one of the safest modds I have done.

I had professional help... but all the hand labour was mine

I am taking it easy now.

Regards

Ricardo

Ricardo you seem to do things well so I would'nt worry about over doing it. Some people just manage to blow up stuff by looking at a circuit board hehe

Brent

[Thomo]

Originally posted by rowemeister


But you got "professional help" on the CD94 LOL

Brent

LOL.

Lee

[jnewbold]

Hi Ray, Brent, Martin and others,

I hope this is not too off topic.

Although I have a Rotel RCD965BX, a lot of the information and discussion on this thread applies to that player too, especially the discussion about multiple regulators and transformers. Following this thread, I now have a total of 13 regulators (and 5 transformers) installed, all of them the superrayreg type with LM317/337. Although the Rotel has only a ground plane and plated through holes for the ground pins of caps and regulators (no grounfd taces at all), I have taken ALWs advice and connected the adjust pin (Kelvin sense point) directly to the ground pin of the relevant chips.

All the regulators are mounted within 4cms of the relevant supply pins and I took Martin's advice and caution about having large, low impedance, caps at the output of the regulators. I used 100uF 10V Rubycon ZL caps as the output/smoothing caps. The impedance of these is 0.3 Ohms and this seems to work just fine.

Rotel uses a single NE5534 op-amp per channel in the output stage and I have changed this to an LME49710, which is the single version of the popular LM4562.

Each change brought a significant if small improvement. The three major improvements were installing a Tent XO module with its own psu, changing to the LME49710 op-amps with separate transformer; and separate regs for each DAC supply, also with separate transformer winding for analog and digital. The SAA7323 DAC now has 6 regulators - 2 analog and 4 digital.

I have been watching the discussion about the Discrete Output Stage and have been wondering whether I could use part of it to replace the op-amp. I don't think I need the bessel filter part of the circuit so I'm thinking that I could leave that off the pcb and use everything from T1/T2. My idea is to tap the signal from the DAC just before it enters the op-amp, bypassing it completely, and use the DOS as if it were a discrete op-amp. I think the original op-amp in the Rotel has a gain of 1.8. Would I need to change anything on the DOS pcb.

Can I buy the DOS pcb anywhere?

Thanks for all the information and discussion and congratulations on such a useful thread.

Joe

[RCruz]

Originally posted by rowemeister


Ricardo you seem to do things well so I would'nt worry about over doing it. Some people just manage to blow up stuff by looking at a circuit board hehe

Well, I use googles to stare at the PCB.... maybe that is why it does not blow on first sight.... LOL.

[RCruz]

Originally posted by rowemeister


Ricardo you seem to do things well so I would'nt worry about over doing it.

Hi Brent

Following your pdf, I built a PSU for the decoder with separated windings for Digital and Analog.

After some reading (and your last e-mail), I understand that all psu lines in the decoder should be connected to the same external psu.

Does this mean I can not separate analog from digital using two separated psu´s ?

Regards

Ricardo

[SimontY]

Ricardo,

You can separate them, it works fine.

The only thing I've found you really can't do is to have off-board power supplies for the add-on clocks!! Mine are now internal and as well as detail increasing (they are better power supplies and we did another mod) my noise problem pretty much dropped off.

Simon