What is this thing?

[FlowersForHuman]

I bought this off ebay on a whim for cheap and was wondering if anyone knows who makes it and/or what it was originally for. It has no labels but was advertised as a guitar distortion box/booster, and it seems to do that fairly well...more like an overdrive sound. Also, it is apparently an early 60's unit, and I believe it by the fact that the circuit is housed in a molded plastic housing and the capacitors are gigantic and green, haha. It has what might be production numbers PC-603 and MM-2 penciled into the inside. What im wondering is why it has a built in mounting flange thing on the back (maybe for a mic stand?) and why it has 3 inputs/1 output. I guess perhaps for multiple instruments to run to the same amp? It actually sounds really damn sweet for what i paid. It would be interesting to mod it to run through itself two or three times for a fuzz effect.

http://www.exemplaryrecords.com/Picture109.jpg
http://www.exemplaryrecords.com/Picture110.jpg
http://www.exemplaryrecords.com/Picture111.jpg

[modernkicks]

Not a clue. It'd be a nice "mystical studio piece" though. Y'know...

"what's THAT thing?!"
"If you don't know, I'm not going to tell you "

[RodC]

Looks like a small passive line mixer.

[blakbeltjonez]

sure looks like a 3 input, 1 out passive mixer, but on closer look i see there's a battery clip in there too so there's probably some very simple transistor boost circuit - looks like some sort of epoxy potted module in the corner of the box. maybe the module is to buffer the ins & outs and coincidentally provide a bit of gain since the inputs are all passive. maybe the green film caps keep the tone consistent with varying volume levels? just a guess.

[FlowersForHuman]

All very good assessments after considering the sound it produces. Tomarrow i will try to split my signal and try running 2 and 3 of the same guitar output into the in's. It is interesting about the caps because when the unit is switched on, the volume knob will completely kill the signal like the volume knob on a guitar, but when its switched off it will still attenuate to almost no signal at all. The volume does not seem to boost the signal at all, only attenuate it. Also, when played in front of amp distortion the unit is very noisy until it's "gain" knobs are turned all the way to ten, the point in which they seem to click into place...at 10 it is almost completely silent. It also adds a light and smoothe compression to the signal...but perhaps this is the case with all good distortion boxes, i have only dealt with the ds-1 and a remake TS, neither of which have the compression characteristic. Also, the other side of the plasic labels are labels for a differnt unit from the same manufacturer, for what seems to be some type of modulation unit, so obviously it wasnt a completely custom effect. I just love finds like this!

[floid]

erm, care to do a schem with cap values for us DIYers?

[FlowersForHuman]

Maybe about the schematic, ill try to get some help from my EE friend for that. Dont know if i want to break open the little black box though to be honest. So i played more through some differnt amps and it seems that it was made to be a clean boost that only lightly distorts when it clicks in at 10, but always adds just a touch of compression. Works better than the treble booster i bought for about 6 times as much. Really tightens the low end on my orange.