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
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
Thomo said:
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
Thomo said:
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
RCruz said:
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
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
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
Hi Brentrowemeister said:
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
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
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
Hi SimonSimontY said:
I´m glad your CDP is in working order again.
All my psu´s are internal (well... almost everything because I had to bolt the dac TX outside the back plate)
Maybe that´s why I never had any noise issues.
How do you compare the sound with the philips ?
Thank you for the very informative and explanatory e-mail Brent .rowemeister said:Of course you can seperate, more seperation the better
I finally decided:
1 TX winding will feed both decoder analog and HF/RF amp, using separate regs.
1 TX winding will be used for decoder digital pin15 + pin44, using only one reg.
I will do it in the weekend and report the results ....!!!
RCruz said:
Ricardo,
The Philips is warm and lush, having massive bass weight and a very chunky representation of instruments and vocals. Detail retrieval is average at best and treble is dull. It makes music interesting in spite of its obvious flaws.
The modded CD63KI, by comparison, is fairly bright and strident. The bass is lighter, but with excellent pitch, pace and detail. Vocals don't always seem as characterful. Treble is clean and sweet. Detail retrieval is stunning. The sound is balanced top to bottom.
Both players stock I think you can guess which I'd be listening to! But the CD63 is so darn modified it will take some beating. If you're curious about the TDA1541 I can say I've heard Lee's modded CD94, in my home, and it was just about preferable to my CD63. However, the bass was a bit thick at times and it wasn't as clear sounding on some material.
If I could start again it would be with a CD94. I also like Brent's modified CD17KI FWIW, it has all the (massive) bass weight of a CD94, but sounds much clearer. I've not heard it at home so can't really vouch for how it plays music.
I've also had a listen to some lower end Naim, some Rotels, Cambridge Audio, other Marantz players and DVD players (modified) and they all sound quite mid-fi compared to CD94, 63ki and 17ki (all v modified). I've not heard a player that isn't begging for mods yet
Simon
RCruz said:
Hi Simon
I´m glad your CDP is in working order again.
All my psu´s are internal (well... almost everything because I had to bolt the dac TX outside the back plate)
Maybe that´s why I never had any noise issues.
How do you compare the sound with the philips ?
Thank you for the very informative and explanatory e-mail Brent .
I finally decided:
1 TX winding will feed both decoder analog and HF/RF amp, using separate regs.
1 TX winding will be used for decoder digital pin15 + pin44, using only one reg.
I will do it in the weekend and report the results ....!!!
No problem
Let us know how it sounds
Brent
Hi SimonSimontY said:
Ricardo,
The Philips is warm and lush, having massive bass weight and a very chunky representation of instruments and vocals. Detail retrieval is average at best and treble is dull. It makes music interesting in spite of its obvious flaws.
The modded CD63KI, by comparison, is fairly bright and strident. The bass is lighter, but with excellent pitch, pace and detail. Vocals don't always seem as characterful. Treble is clean and sweet. Detail retrieval is stunning. The sound is balanced top to bottom.
I've not heard a player that isn't begging for mods yet
As usual, your reviews are very well described.
I totally agree with your last comment.
This is Simon and he writes with with a quill pen under candle light. LOL
Mine still needs a tweak or two and I don't seem to have the time to do so
I'm going to change my clock psu(s) BHC Aerovox caps to Mundorf types which we have found brings more detail than the BHC. I also need to remove the 4 remaining Audiocom super regs and replace with SPowers for the HF RF Servo digital and analogue supply + fitt them more direct to the circuit.
Brent
An externally hosted image should be here but it was not working when we last tested it.
Mine still needs a tweak or two and I don't seem to have the time to do so
I'm going to change my clock psu(s) BHC Aerovox caps to Mundorf types which we have found brings more detail than the BHC. I also need to remove the 4 remaining Audiocom super regs and replace with SPowers for the HF RF Servo digital and analogue supply + fitt them more direct to the circuit.
Brent
SimontY said:
Good good!
I could not imagine that you looked like that
Nevertheless, your reviews are much more precise than the majority of informations I am used to read in Hi Fi News and other publications.
You seem to have a special gift regarding writing about how machines sound.
Hope I could be so fluent.
Regards
Ricardo
PS.... Here´s a pic of me and my son
Attachments
jnewbold said:
Hi Joe,
Rotel makes some very decent players, I recently fitted a Flea clock and some opamps in a RCD991
.The SAA7323 needs at least one opamp (or some other type of buffering) behind the internal switched capacitor network, which cannot be loaded too much. Maybe a FET output stage does the trick, but you probably need some kind of filtering. The device has only 60dB stopband attenuation. Loading the network with the passive version is out of the question
.I'm afraid I don't have any DOS PCB's left...
Regards,
Ray