Rotel RCD 865 Mod, AD847 vs OPA627

[KP11520]

Hello Everybody, I am jumping into the water as a new DIYer and I am either going to have an even finer sounding CD Player or burnt toast! The 865 already sounds pretty sweet for an older, not too expensive CDP. I look forward to it sounding even better. While emailing with a great Tech Support guy at Rotel, he suggested only one Rotel approved Mod. He said to replace the two XR5534A op amps with two AD847 op amps and to replace four 18 ohm resistors R219, R220, R225 and R226 with wire jumpers. I saw previous posts and saw all kinds of suggestions (many were over my head) but none suggested the Rotel approved Mod. The most popular was to replace the stock op amps with the BB OPA627 op amps and do something with resistors and Caps. Anyone know from experience which is better?
I appreciate all suggestions, ideas and opinions, especially the ones based on actual listening experience and satisfaction with these Mods and even better if they have been done on a RCD 865! I thank you all in advance and look forward to sharing all my successes and burnt toast too! Anyone have any jelly?

[KP11520]

Anybody???????

[KP11520]

Wah!, Nobody wants to help me make my RCD 865 be the best sounding it can be! Wah!


Please! I am open to all ideas! If it is over my head, I am certainly willing to give it a try! Thanks!

Regards//keith

[Netlist]

If you are serious about your 865, which for the record I don’t know, you need to start with a service manual, at the very least a schematic.
A more then basic understanding of the processes is highly recommended if you don’t want to work as a parrot or blind man. Experimenting with well targeted parts of the circuit, one by one, followed by listening tests is the proper way to go.
Of course this is DIY and shouldn’t be taken too seriously but working systematically can save a lot of frustration.
Here’s one tip as a starter: I read that several connectors on the PDM(?) board tend to have bad connections. Resoldering or eliminating them by wiring directly to the board should cure that.

/Hugo

[shepperd]

The above advice is of course very sound but some of us have to be parrots because we lack the basic skills and understanding. For reasons known only to the audio gods, there are 600+ pages devoted to modding the Marantz 63/67 series. If you have the courage to read it thru from the beginning you will get a very good idea of the whole process, even if like me you don't understand half of it. Every now and then a nugget will appear that I can slavishly follow to the letter! Having said that, DIY'ing is not for the faint-hearted and any sloppyness will get you toasted parts or a dead machine. DON'T take this as gospel PLEASE, but if your player acceps the 627's, do your self a favour and use
LM4562 instead. They are much cheaper (free actually if you are lucky and they are still being given away for trial), can be plugged right in and past their burn-in period (around 100hours on my CDP) sound bloody marvelous. Of course the benefit of doing this may well depend on doing other things as well
ps another tweak (that will probably get me a slap on the wrist) is to remove the internal fuses and solder a FINE, good quality piece of wire (I had some silver wire from an ancient project that I bought from the people in the UK who made the Passion passive pre kits) across the fuse holder legs. I don't need to tell you to unplug the unit first do I! This is a contraversial tweak but I had an emmediate reduction in subliminal 'dirt'. Soldering a decent power cord in place of the fixed one is also an easy upgrade, assuming it is the fixed type and easily accessable. Cheers!

[awpagan]

KP11520

Do you really want to disable a good working CDplayer?
Do you have anything else to use while the mod's are taking place?

If your not used to modding or even soldering you can be your own worst enemy....

first you need to find some info about your own player
It will probably have a Philips equivilant, maybe a cd850 MK1 or 2.
A picture tells a thousand works..
A schematic tells more.
what dac's are used?

the marantz cd63/67 link is very informative on different ideas which can be crossed to other players but,..... you need to find the dfferences in your player too.

opamps? the 5534's are single amp 8pin package
each brand opamp has it's own characteristic, use a socket and try different ones.

allan


http://www.diyaudio.com/forums/searc...der=descending

[Fin]

KP11520, the other thread on the RCD865 that you are involved in, has links to the service manual for the CD player in question. With a little bit of searching, you can easily find the schematics and even photos of the internals. This way you can learn about this CD player and plan all of the mods - without even opening the CD player. This will also reduce the risk of ESD......please remember to work ESD safe!!!

In summary, it has a Philips CDM4/19 mechanism, SAA7310 decoder and SAA7323 DAC (Ist generation Bitstream). The closest Philips machine is the CD624. It has similar components but a different layout.

KP11520, you are not going to get any definitive answers on exactly what to do with your CD player. Everyone has a different idea of what sounds good and what mods bring an improvement. Some mods (like just exchanging components) don't necessarily bring an improvement - just a change in sound. Other mods like improving the power supplies, circuit layout, grounding and clocking can bring meaningful gains.

The best you can do is to spend a lot of time reading and learning.....before you start soldering. Most of the general mods can be applied to all CD players with a little adaptation.

[shepperd]

ESD=easily self-mutilated? All the above is wise and level-headed.
But when you do do something right (it still works!) and it sounds better (well different anyway) what a rush! ever day I look at my Marantz and say to myself "hey dude you actually changed out that laser block and it actually not only works but it cured the problem!" This is beginners luck, don't knock it! Actually the way to go is to buy a 2nd hand Marantz off e-bay and be prepared for the long hawl, maybe even kill something. That way you can either enjoy the fruits of your labor or find that Diyng is not your thing! If you succeed you will have a player that really sings for little dough. Don't hesitate to keep asking. Someone will have the patience to talk you thru it. Back to the Marantz thread! good luck and don't get discouraged.

[KP11520]

Gentlemen,
I want to thank you for getting involved! I appreciate and need the direction. I already have the Service Manual and Schematics from the great Tech Guy from Rotel (first and foremost). I will read all the Marantz Mods (for quite a few days it loks like) to get an education and maybe even a little more confused. Allan, thanks for the hyperlink to Fin's posts. I will learn from that too. I will do only one Mod at a time and the listen for a while. If I do more than one at a time I won't know which one negated the better results. So one at a time only! I will be calculated and neat and precise. I will wear a grounding strap and have a Hakko soldering station (ESD safe). I have desoldering braid (wick), but am open to better ways). I will do my best to practice sound procedures and with a little luck (I will keep my fingers crossed - see above) I will make you all proud! We all had to start somewhere and this is my somewhere! After all, I can't be a Newdie, I mean Newbie forever!

The first Mod will be the op amps. I am leaning towards the 847s because Rotel Service used to do this for their customers and this Mod is straight forward. It seems that the 627s get the most praise but there are additional mods required to tweak the mod to bring out the best results. It seems there are many different opinions on how to achieve these tweaks (jumping pins on the op amps with different value resistors and/or adding Caps somewhere) but there is no general consensus. That worries me because I only want to do this once to reduce my risk of detroying the board. Sockets are a good idea but once you make a decision you have to desolder the socket and permanantly solder the op amps for best results (purist). That's two more times than I want to risk. So the decision will be well researched and thought out and the Mod will be done once unless something significant forces me to change it! This is where I need a quorum to choose the 627 over the 847 and have a significant percentage of you agree on how to tweak these op amps otherwise I will get the 847s from Rotel directly ($17.20 ea.).

After that and listening for a while, the clock will be next. I read that that Mod gets amazing resulrts too! When I get to that point I will need your help with which one and the procedure.

After that IEC inlet with better wire to the power block and better power cord.

Maybe after that, this is up in the air, removing the muting transistors (Ah! Njoe Tjoeb uses a relay instead and that is a good idea but not an option on this unit). I am not sure if I should just remove them or jump them or leave them but I am nowhere that decision or Mod.

And maybe after that, replacing some of the componenets (Caps, resistors, etc.) with higher quality ones.

But back to Mod 1. So gentlemen, is there one definite way to get the most out of the 627s that most agree on or will it be the 847s?

I want to thank you all for my education!

Looks like its time to get this Mod going!

I look forward to your replies!

Regards//Keith

[Netlist]

I have nothing to add…you are a great disciple.

Good luck on your journey.

/Hugo