Discussion in 'Pro Audio Equipment' started by bpatram, Jul 26, 2006.
Unfortunately, the 3630 is a bargain unit. Most of these bargain devices are almost not worth the effort to repair since much of it is now surface mounted components. I've never opened up one of those so I'm really not certain?
Are you sure you are engaging the stereo coupling button? Your stereo mix will not sound right if you don't. The image will appear to wander from side to side. If you have engaged the switch and levels still do not seem right, try feeding both channels from a single monaural source and see if the problem continues? It might not be the VCA? It could be an output or input Op-Amp problem? Feeding both inputs from a mono source while monitoring in stereo should reveal whether the VCA is doing its job. You can make up the level difference on a console in that way, you can definitely tell whether gain reduction is happening or not, equally for both channels.
Everything that starts off cold, whether it's tubes or transistors all has to warm up. I used to marvel over the fact that it actually took approximately 3 hours for our Ampex and MCI 24 track recorders to actually stabilize, even when they were new! I use to work for Scully and they weren't any different either. So perhaps a good one half hour of warmup is in order for your 3630 to finally start to function consistently?
Remember, never try to feed a stereo signal through a stereo limiter without engaging the stereo coupling switch. If you don't, everything you do will make you sound like an amateur.
Ms. Remy Ann David
Ms. Remy Ann David
There's a lot you can do on your own, just in terms of simple maintenance and perhaps sort out the problem. (I agree with Remy in principle, it's probably not worth fixing; BUT if you're up for it, you might learn a few things in the process.)
Get a good Volt/Ohm meter and check for basic stuff. Dunno if it's a bipolar power supply or not, but it's possible. Be VERY careful when working with the AC side of the power supply (esp if it's plugged in!). Always work on live stuff with sneakers on (no bare feet), standing up, and one hand in your pocket. I'm serious.
The unit is certainly small enough in that you could re-solder just about every joint on the thing (esp anything that looks suspicious). Use a magnifying glass if you're in doubt, and check for cold solder joints, extra blobs of solder, etc. (You don't want to make things worse than when you started). You may end up "curing" it by simply gently heating and applying some new solder to each connection.
You could also replace all the ICs with sockets and then reseat them. This makes it a little easier next time you have to do some work on it. (With ICs in sockets, you can also do A/B testing a whole lot easier...it's a miniature version of parts-swapping at the chip-level, but sometimes it'll get ya outta there in a hurry.
I'd also check any and all caps; esp if they're electrolytic and prone to drying out. That may be part of the problem, as well.
Of course you'll want to clean all pots and in/out jacks, sometimes that's all it takes. If it's a balanced i/o circuit, make sure the tip, ring and sleeve pins are all solidly connected to the circuit boards and are making good contact when a plug is inserted.
have fun, and try not to blow anything (or yourself) up in the process!
There is an online store-Black Lion Audio-that offers upgrades and service parts for the 3630. My service tech did mods to a couple of 3630's and they actually turned out pretty well. That box, as from the factory is a POC, but the Black Lion mods really cleaned up the sound and stabilized their operation. Google Black Lion Audio and check 'em out...
BTW, I learned about these guys on this forum. There has been a lot of positive response regarding what the mods do to the 3630 and they also do other less-than-stellar boxes. You can only shine a turd so far, but they make 'em decent!
The one hing that you DON'T want to do is replace the opamps in that thing with the same ones! You want to go with the upgraded Burr-Browns that Black Lion offers....the opamps are the source of most of the problems...!
I see by their website that they are discontinuing those kits (they had 2)this week! YIKES!!! You might e-mail them and ask about the "real" manufacturers' part#....
Again, make sure you put in sockets for those ICs. If you are going to go through the hassle of taking the old ones out, do yourselves a favor and put in sockets, so the next repair/upgrade will be nothing more than pulling a chip out.
Careful with the soldering iron and use a wic, too!
A quick thing to ask/comment...
You did label/mark which original opamp came from which side, right? If so, break out the sloberin' iron again, and replace the waeker side with the stronger side original.
With any luck, they'll be fairly close to each other... just a thought.
If you want to play around with it further, you may want to check this out:
Thats good reading and info thanks. The old opamps are destroyed as I had to cut them out for a better removal. I just find it interesting that I replaced both and the result was the same uneven return but on other side. Granted they were not the same brand, maybe I'm getting closer to the solution. I'm not sure if its the left being too low or the right being too loud. I'll deal with it though. I think I am just going to put it in my PA rig for ducking only, maybe I will open it up again some day.
Looks like I missed my chance to have the Black Lion Audio 3630 mod, I even asked if they were selling a parts list but to no avail...
Does anyone have the parts list?
do a search over at the LAB
see above for link
but someone else there may have done that one
there is a few other 3630 mods and fixes
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