How to install opamps on CD player?
Before I get to the details I gotta say that I am very much a newbie at this sort of thing, so please bear with me :)
Okay, I have an Rotel RCD965bx that I am playing around with since its kinda old ... and quite frankly I love tinkering. So far I have put in a Trichord clock2 and it made a big difference. I have also heard that replacing the opamps in the unit will make a nice improvement too. The Burr Brown OPA627 opamp was recommended to me so thats the one I am gonna go with. (plus I know a local place that has some)
On the CD's circuit board I found the opamps (there is one per channel)
and here are the ones I want to put in there place:
Now the questions:
1.The store I know has the OPA627AP chip. Is this the right one for the job? (I am assuming I would need two of em in total)
2.How do I take off or bypass the old opamps? They are soldered directly on the board! .. snap em off?
3. Can I just drop in the new opamp (assuming its oriented the same way) and resolder the same pin outs
4. Am I in over my head? :)
Any help would be appreciated. Please keep responses VERY straight forward.. I am very much a newbie in both modding and electronics in general. I do know how to solder .... but not much more than that.
The OPA627 is a very good op amp but for your elderly CD player maybe a bit OTT! Check out some others that will be much cheaper.
As regards removing the 'old' ones, yes you must desolder them carefully and then solder in the new ones. Use solder braid or a solder pump.
Not all opamps will work though so you will need to find somebody here knowledgeable enough to recommend specific types.
UPDATE: Cd player
I figure I will post about how the upgrade went down so that others in the same situation will have something to go by. Uhhh <disclaimer> ... I am a newbie so donít assume I know what I am doing cuzz I really donít... you could permanently, completely and totally kill your CD player doing this ... I was pretty lucky now that I think about it </disclaimer>
Well a couple weeks ago I finally received the 2*OPA627 op-amps (allot off ppl suggested they would be overkill and I should try the 132's but thought what the hell and splurged ... got some isophorm(?) feet too). BTW: The techie @ partsconnextion said that the opa627's were electrically compatible with most players and I should be able to just drop em in. He recommended soldering directly to the board for maximum sound quality.
So I got out my radio shack *cringe* soldering iron and let it warm up as unscrewed the top of my RCD-965bx. I tried lifting the PCB up but it was connected with so many wires to so many places I couldnít totally remove it from the chassis without unsoldering a bunch of stuff ... so I left it in the case and tilted it upwards as best I could.
My original plan was to use some de-soldering wick to get the Op-amps off. I put the wick between the iron and the bottom side of the PCB where one of the soldered op-amp pins was ... and theoretically when the wick gets hot enough to bring the solder on the other side to its melting point ... it should soak into the wick. Well that turned out to be kind of impossible. Getting the tiny amount of solder that was on the PCB to soak into the wick proved to be futile.
So after about an hour of non-progress utter frustration ... out came the pliers! Muhahaha :smash:
I was fed up and decided to just pry and yank the OPAMPS off. And ... it worked ;) I was careful not to break the PCB and simply moved the pliers in a back and forth motion in order to weaken and eventually break the metal pins of the OPAMPS. Needless to say the OPAMPS did not survive the process.
Once both OPAMPS were off, I was left with the bottom half of the pins from OPAMPS still residing in the solder on the board. So I painstakingly heated the solder and pulled what was left out one by one (8 pins per OPAMPS, so 16 pins in total).
A slight problem arose one I got to this point. Since I really didnít de-solder the OPAMPS, there was solder still sealing the 16 holes where the new OPAMPS pins should go. Yeah ... a problem. After tinning all the pins on both OPAMPS (something to do while I figure a way to get around this problem), I decided to lay the OPAMPS on the now horizontal PCB, in the correct orientation dictated by the PCB (pins down, notch on OPAMPS pointing same direction as OPAMPS diagram on PCB), and add some solder to the pins.
One by one I heated each pin to solders melting point, with its pointy end touching where its supposed to be on the PCB. I would add a tiny bit of fresh solder to the pin where it touches the PCB. The trick was to get the new solder to meld with the old stuff still on the PCB, thus making a half decent connection. After a bit of practice (3rd or 4th time) I had it down pat.
(all you expert solder Ďs will probably cringe at what I did... but ... again ... I am a newbie :D )
To make certain that each pin was securely soldered to the PCB, I used a small screw driver to lightly move each pin. If the pin moved at all ... then it wasnít soldered. If it was solid and wouldnít budge .. it was fine. Turns out a few of them werenít soldered correctly so I fixed those ones and test all the pins again. And then twice more to be certain I didnít muff anything else. I also looked closely between the pins to be certain I didnít accidentally bridge to pins or something ... that would have been bad.
After all was said and done, I took a deep breath and reminded myself that I probably just destroyed a perfectly nice cd player, then plugged it in and ....
The power light came on. And I let go of my breath which I didnít realize I was holding.
I carefully pushed the eject button and put a cd in the tray and pushed the button again. It read the disk and displayed the track numbers. I figured I should see if the OPAMPS are overheating (a sign of too much voltage i.e. they arenít electronically compatible) and they were slightly warm to the touch. So then I pressed play and ... nothing :(
After having a small heart attack realized that I should plug the CD player back into my preamp *bonk* :)
So so ? did it play? ... Yup! And man what a difference too. There was always a muddy lower midrange with the player which has now vanished. I know the cheesy audiophile words are well.. cheese ... but the only word I can use to describe it is liquid. I am very happy with the player now. I doubt I will buy another (well until it dies of old age).
So, for ~$70cdn? ... amazing upgrade. Frikkin amazing.
Anyone have any other ideas on what I can do to my guinea pig player? :-)
Glad you got it to work. Next time, you might try putting some solder flux on the area to be desoldered. It helps draw the metal up into the wick. You can get flux in bottles or pens. Also try pre-heating the wick.
For further upgrades, I suppose you might replace the rectifiers or their snubbers, or other power supply components, or replace the clock.
You don't sound too old...judging from your actions! :D Nonetheless, I like your adventurous spirit. People like you are a dying breed.
Since you are at it, can you describe more about your sound improvement?
As for your other suggestions, i am not to sure what rectifiers or snubbers are, could you clarify? And the clock has already been replaced with a Trichord Clock2 (they are only ~$100cdn since the new Clock came out).
I was also thinking of upping the power supply components but I figure I will need to do some reading into how power supplys work before hand.
An easy upgrade that was mentioned to me was to remove the mutting transsistors. Any idea where those might be or what they look like? (i think i need to get a service manual for that ... probably will help with upgrading the power supply too)
As for the sound, well a big thing was the improvement in clarity. Voices seem alot more clear and real. It sounds alot like I am in the studio while they are recording, as apposed to feeling like I am listening to a recording of them in the studio. As I stated before there is an overall liquidity or even a fast n easy smoothness to the sound that just wasent there before. The bass is abit punchier too.
On the down side the sound is still pretty laid back. I would like it to grab me abit more i suppose.
gad i sound like those stereo***** magazine reviews :)
So in general the sound was just clearer, and gives me a better feeling of bieng there.
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