Rotel RCD-02 Definitive Modification List

[colonelkernel8]

Well, I like the idea of modding my Rotel RCD-02, and I think there are others who share this thought. I think it is time we compiled a conclusive list of compatible mods and their value to the sound quality of the RCD-02.

The Kwak Clock (Or other generic clock upgrade)
Upgrading the rather poor master clock in the RCD-02 with a low-jitter alternative will yield significant improvements in the clarity of the sound as well as reducing glare and making a general improvement across all frequencies. Other aftermarket clocks will suffice here such as solutions from LCAudio, Tentlabs, etc. The frequency is 16.9344 MHz. Installation of the clock depends on what type of power supply the clock has (whether it is on board or stand-alone). For connecting the power of the clock, keep in mind that the RCD-02 has no negative digital supply and that the positive digital power can be tapped from the capacitor C907. The connection of the clock output is uniform between varieties however. First, remove the two small ceramic caps C634 and C633, the resistor R631 and the crystal X631. The goal is to have the clock's output connected to pin 1 of the HCU04 IC and the ground to pin 7. This can be achieved by connecting the clock output to left pad of the original crystal. The ground can be connected to either pads of the capacitors that are connected to the ground plane. Price: ~$100, well worth the cost, this mod yields the greatest sonic improvement over any other single mod.

Replacing Op Amps
Perhaps the simplest way of improving the sound of your RCD-02 is replacing the two Burr Brown OPA2704 opamps with a higher quality solution. The general consensus is that the AD8620 opamp mounted on a SOIC-to-DIP adapter from Brown Dog is the best suited and best sounding for this application. The installation is simple. Desolder and remove the OPA2704's and replace them with 2 high-quality 8 pin DIP sockets. Then simply plug the AD8620's on BD adapters right in making sure that they are oriented correctly. (With the front of the CD player facing you, the square pad on the adapters should be on the lower left hand corner). Then burn-in and enjoy. This will yield less grain and an overall improvement in transparency and clarity. Price: ~$32, well worth the money, a gateway mod.

Please post all your suggestions. Don't forget to include the benefits (or even side effects) of your mods as well as the cost and value estimate.

[ckng]

Hi,

I found a good place to tap the raw digital power is actually from pin 5 of U931 (the side closest to C932 and the HCU04 chip. Just solder the wire onto the pin. That is what I did for mine.

I am using this locally made clock which has the TentLabs XO on it. Output is fed into pin 1 of the HCU04. However I accidentally left the R631 in circuit. Still works but I suspect removing it might improve things a little more. Using this made quite a good improvement over the stock clock and removed much of the digital glare which the player originally had. This made for a much more listenable and musical player.

The other popular op-amp to use is the National Semiconductor LM4562 which I am using now. Others worth trying are probably the Burr Brown OPA627, OPA2134, etc. OPA637 does not work well, probably due to insufficient gain.

The next thing I am going to do is to replace the coupling and outputcaps (C667/668, C717/718) with BlackGate N series and see how it goes.

There are also people talking about replacing the power supply caps with better quality ones, as well as replacing the 1N4003 diodes with Schotky types, which should also give an improvement.

Regards
CK

[colonelkernel8]

The two large Rubycon caps are for the analog stage right? Would upgrading those help anything. I want to ask first because it will be a pain to remove them (they are glued down).

[ckng]

Originally posted by colonelkernel8
The two large Rubycon caps are for the analog stage right? Would upgrading those help anything. I want to ask first because it will be a pain to remove them (they are glued down).

What are their C-numbers? My player is currently playing some music and I don't have it open to check which are the big caps. :P

Hmm, are we the only 2 with a RCD-02?

Regards
CK

[colonelkernel8]

They are the two largest caps on the board. Can't miss them.

I think I am going to get that Effective Audio Mod clock. I got a Kwak Clock, and I unfortunately mussed it up real bad. There goes a $100, sigh. No solder mask = pain. My question is, can I order them online? If not, could you pick one up for me and I'll paypal you the money.

[colonelkernel8]

Scratch that, I got my Kwak Clock working.

[ckng]

Ok, I just opened the player up to replace the output and audio coupling caps (C667/668, C717/718) to Black Gate Ns. The 2 big caps which are glued to the board (C955 and C956) are power supply caps. From the schematic they are indeed for the analog stage. Replacing them with better quality ones should give an improvement, but like you said they look like a pain to remove....

Regards
CK

[coolmaster]

Originally posted by ckng
The 2 big caps which are glued to the board (C955 and C956) are power supply caps. From the schematic they are indeed for the analog stage. Replacing them with better quality ones should give an improvement, but like you said they look like a pain to remove....

I've had a look at some other cd player schematics (comparable models) and they've implemented same value (uF) capacitors, some even less. Its more than sufficient for its purpose & intent.
Its perhaps prudent to leave them alone and upgrade other areas.

Damp the chassis with adhesive damping material, that's one essential tweak. It's implemented as standard on my RCD-971, although not fully or as I would have desired...perhaps I'm asking too much.

I must say and agree, re-clocking proved the best and most significant improvement in the sonics..period.

Where I reside, Analog AD's (with adapters) is troublesome to obtain and I've settled with LM6172, which IMO, best bet. There's been so much hype about LM4562, but my experience in the Rotel was not entirely satisfying as the former and, not quite as I would have expected or desired...and anyone have the right to differ from my own opinion.

[colonelkernel8]

Yeah, replacing those two big caps wouldn't yield much improvement considering they are already nice Rubycons.

I am considering replacing every electrolytic cap in the player with Elna Cerafines (except the glued down ones). Now that would look (and sound) awesome.

[CRNIC_IVAN]

does anybody have experience with replacing OPamp chip with discrete opamp?
NewClassD Discrete OPAMPs
Thanks