WHY Does ROTEL 855 sound so good ;really just a Philips player

[homemade]

I just picked up a 15yr old Rotel 855 cd player to compare it to my 'modded' Magnavox units. The Rotel really is an over achiever. But it's just a basic Philips( tda1541) designed circuit , small power supply, no fancy decoupling ,,a few Blackgate caps(not even their best ones), and NE5532 op amps for i-v/buffer. Yet this thing just kicks butt! The bass shakes my room(not boomy) and sound stage is HUGE , better than my old Sony 707es , Revox B226(S1 dac) and subjectively nicer mid-range than MY modded Mag. 650 with stiffer p/s , decoupling , AD826 op's and poly. output caps , amoung others . Can it be as simple as the circuit board layout? There's just not anything about this player that stands out(design) , yet it performs brilliantly. Anyone know the secret? I would like to 'improve' it but I'm afraid to ruin it. I guess a good clock can't hurt?? Thanks

[Fin]

They just put all of the right stuff together in the right way. the design and layout of the PCB is important. They also used all full size components instead of some lower quality surface mount items. The chassis is also quite good being all metal and providing good shielding.

[aparatusonitus]

Hi homemade,

I have it too, and I can only second your findings. What I did is a nonos mod which push thing even further in right direction, becouse it bypass jittery SAA7220 filter out of digital chain (not that the jitter is lower, just the susceptibility on it, as I understand)

How to do a nonos mod and restore a mute function is described in images below...

http://www.diyaudio.com/forums/attac...amp=1160298369

http://www.diyaudio.com/forums/attac...amp=1160298481

[homemade]

Originally posted by aparatusonitus
Hi homemade,

I have it too, and I can only second your findings. What I did is a nonos mod which push thing even further in right direction, becouse it bypass jittery SAA7220 filter out of digital chain (not that the jitter is lower, just the susceptibility on it, as I understand)

How to do a nonos mod and restore a mute function is described in images below...

http://www.diyaudio.com/forums/attac...amp=1160298369

http://www.diyaudio.com/forums/attac...amp=1160298481

Thank-you for confirming my impressions. Sometimes ,just because something is different , it's 'better'. As I continue listening for much longer sessions , I can heard some of it's shortcomings , however small. But the one aspect that cannot be ignored is the ability to draw you into the music. Very emotional
. Anyway , I may just enjoy this player for awhile before I 'fix' it. A very excellent foundation to build on. I'm suprised there is no Rotel 855/955 mod thread here. Anyone with hands-on experience tweaking this , please pass it on.

[Fin]

Here's some info...

And here....

And here....

And here.....

[homemade]

Originally posted by Fin
Here's some info...

And here....

And here....

And here.....

Fin

Thank-you! Good links. Just what I needed.

[aparatusonitus]

homemade,

If you need a service manual for RCD855, just e-mail me.

[Fin]

Also - if you do some general searching on CD players like Philips CD620/630/640/650 and Marantz CD40/50/60...you will find lots of ideas that can be applied to the Rotel. The PCB's are a bit different but the idea is the same. They all use the same CDM and chip sets - except for the decoder - some use SAA7210 and some use SAA7310 (SMD).

[docfin]

Service manual for Rotel RCD-855 available here: http://service-manuals.webs.io/

[tubee]

CD players like Philips CD620/630/640/650

I worked a lot with these machines, easy to mod and fairly good sound achievable. Will try BB PCM56 with glue logic for I2S conversion in NON-OS in time. With schematic to adjust LSB of course, and AD844 or maybe 6922 tubed output stage.