Mixer Modification

[note: a scan of the 32-1200B manual is located here]

I've had my 32-1200B for a few months now and I'm happy with it.  However, I am still quite annoyed by the bizarre way they insisted on wiring the cue channel.  I put some thought into it and determined that it might not be so difficult (electrically speaking) to modify this thing to suit my needs.

So let me set out a scenario: let's say that Deck 'A' is live and Deck 'B' is in cue.  When I listen to Deck 'B' through the headphones, what I actually hear is Deck B in my left ear and Deck A in my right ear.  I don't need that - if I did, I'd just let one of the headphone cups off my ear and listen to the live feed through the speakers.  It is always in the left ear, even if the scenario is reversed and Deck 'B' is live and I am cueing Deck 'A'.

So I figured that I could disconnect the right channel lead to the headphone jack and bridge the left channel across both 'tip' and 'ring' and I'd be good to go.

I found the above graphic online but it tells you all you need to know.  I need to disconnect the lead that connects to the ring and bridge the tip across both via a number of different methods.  So I sat down and cracked the thing open.

This quickly began to get scary as I took off the back panel and both sides, then realized I'd have to literally tear the faceplate off and even then I MIGHT get a glipse of the headphone jack.  The faceplate was screwed down but it was also stuck on with some kind of adhesive.  So I jammed my screwdriver underneath it and gingerly pried it off as carefully as I could.  Then of course, I put it in my scanner.

The manual actually has a very detailed schematic inside and I located the part that covers the headphone jack.  It didn't provide me with much info so I knew I'd have to put eyes on the thing to see how it was wired.

So I finally got to where I could see the thing but looking was about all I could do.  It was held in place with a tiny brace, presumably to prevent it from getting busted from all the in/out, in/out (as my friend Alex would say).  Which is actually kind of cool, and sad that Realistic is basically gone now.  I removed the screws that held the brace in place and even started to try to remove the entire circuit board assembly (there are screws that hold the faders to the top of the chassis, I removed them all then realized there would be even more work to unearth this thing, so I backed off.  I finally was able to reach in there and pull off the retaining clip that holds the jack into the brace so I could carefully pull it loose.  It was actually held on by a ribbon cable! Interesting since they actually put maybe 3" of wire on there, without that this would have been just about impossible.  I attribute this to the difficulty that even Realistic had cramming this thing together when they assembled it.

                                     

Now my next problem was that while it was obvious the yellow wire was the sleeve (and I don't care about that one) it was not at all clear if the blue or white wire was the tip.  There were a couple ways I guess I could have gone about this, but the simplest way that I could think of was to disconnect one wire, then go set the mixer up and plug in the headphones and see which ear got cut off.  

So I did, and of course cut the tip on the first try.  So I removed the blue wire (ring) and then bridged the tip across both points with a very sloppy solder.  And I tested again to make sure it worked - alas, it did.

So after being sure that all was well, I redid the solder as best as I could.  As you can see, I gave up on the solder points at the bottom of the board, they got full of jacketing from the ribbon cable and also some of the black plastic housing that holds the jack.  Some of this was done at the Realistic factor no doubt but I made matters worse.  No worries, just go right onto the board.  Putting this back together was no fun and I'm kind of surprised I pulled it off.  The worst part is that it became more evident (I was already aware) that the headphone pot is pretty beat and if I was going to change it, this would have been the time. (This is ironic since all the faders are in great shape).  But it isn't terrible and maybe I can squirt something in there.  Glad all is well and thank god I have two ears of cue now!