Rotel 855 PICS, dac & opamp question for newbie... - diyAudio
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Old 8th April 2004, 11:33 PM   #1
psonic is offline psonic  United States
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Default Rotel 855 PICS, dac & opamp question for newbie...

Im new at the audio DIY game guys, so thanks for any advice. I just landed this off ebay for under $100 and it sounds pretty decent and build quality is great. I am ready to tinker.

It appears the dac (tda1541a) & opamps (mc34082p) are on sockets. What are some suggested replacements & where can they be ordered?

Also, any other easy mods for this unit?

Can anyone show how to turn the laser up a bit? It is skipping some on lightly scratched cds.
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Old 9th April 2004, 09:14 PM   #2
chlo is offline chlo  United Kingdom
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Hello Psonic,

I just modified my Rotel RCD855 few weeks ago and sounds very good now. the rotel need to be dissambled to remove PBC board and the whole mecs, from there you can:

replace all elecs capacitors (panasonic FC recommeded), change all diodes with stokky (11DQ10),
replace opamps (my one are 2 NE5532s I changed them for OPA2604s), change 14 decoupling cap around TDA1541 for something like Revox Rifa MMY serie and finally put a low jitter clock and PSU for it.

Hope this will help.
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Old 9th April 2004, 10:02 PM   #3
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Hi,
Some time ago I modded this player for my friend.
BB2134 works better than BB2604 in it. With 2604 the sound is very sharp,not that smooth and silk.A little fatique to listen to (I don't know why).The MMY Rifa is quite weak for decoupling.I got much better performance with pink Philips polypropylene caps.1uF/63V.They are 3 times the price of Rifa at my local store (about 0,25$) ,but are much better.

Bartek
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Old 9th April 2004, 10:25 PM   #4
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Hi

A few years backs I done several mods to the Rotel RCD965 apart from op-amps and the Trichord clock,there was a FREE mod that had good sonic effect.

Removing the muting transistors these were located close to the output phono sockets.I did not notice any clicks when stopping or starting playback,but you could hear noise on a scan.
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Old 9th April 2004, 10:56 PM   #5
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Quote:
I did not notice any clicks when stopping or starting playback,
They are there to prevent clicks and pops in speakers when powering the player off and on while the power amp is on (volume control up).

I remove them in every player I have.


B.
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Old 10th April 2004, 12:24 AM   #6
psonic is offline psonic  United States
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Greetings,
Can the muting transistors be seen in this photo, if so can you point them out? Excuse my electronics ignorance, but will I need to bridge where they were or just pull it and done?

BTW, I ordered opa2134 & opa2604 samples (free, yay!) along with a few from analog devices to try out...
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Old 10th April 2004, 07:01 AM   #7
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Quote:
Can the muting transistors be seen in this photo
They are usually located very close to output RCA's.


Bartek
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Old 13th April 2004, 11:00 AM   #8
air is offline air  Finland
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psonic: Check your mail.
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Old 15th April 2004, 11:26 PM   #9
psonic is offline psonic  United States
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Default schematic of output stage

which are the muting transistors, I think I know, but want to be sure before removing? could someone kindly point out from this or the pic above?
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Old 16th April 2004, 06:00 AM   #10
psonic is offline psonic  United States
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try this:
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