Jax Companion VibraChorus Schem & Chassis/Apron layout

[CS Jones]

This was a really nice sounding pedal. Had a substantial volume drop when the Tremolo portion of the circuit was used though. The pedal was probably close to 40 years old so a refresh was probably in order. I've got a 4th page for it explaining (hopefully) a little clearer on how the footpedal switching relates to the make/break section of the relay coil for those of us who don't deal with this stuff regularly. I can't find that page for all the junk that's cluttered around here. Basically the switch was in the pedal heel and you either opened the circuit  or grounded it which in turn engaged the the DPDT switch on the relay to activate/deactivate the bypass.

Some of the orientations for the electrolytics might look odd but I wrote it exactly as I saw it...and I looked several times at what I thought were the wrong orientations. Typically for me I didn't get around to measuring the important voltage points - I got rushed with other things and just simply forgot about it. The pedal was sold (for an ungodly amount) and I no longer have it.

It really was a great sounding effect. Kind of a rare little bird, so I've been told. I'd never seen a schem of the VibraChorus and I couldn't find any posted on the net so it seemed like one that would be worthwhile to spend my time on. If anyone decides to give it a shot I've got a lot of pictures of the insides if you want them. The chassis/apron layout is looking at it belly up.

Take care,
Clay

[Mark Hammer]

For a guy with only 3 posts at this moment, you make a VERY auspicious and dilligent debut, my friend.  A hearty WELCOME.

I believe that there are essentially overlapping industrial ties between Jax, Shin-Ei, and Univox, such that products produced under the one name were also released by the other companies under other names with small component or circuit changes.  In this case it seems like we're looking at a Uni-Vibe.  That's not a waste of time on your part since there ARE some differences between this circuit and the Univox version (and the Shin-Ei "Reslie Tone" too).  

I like seeing slightly different versions of the same basic circuit.  Lets me learn something about what aspects of the design matter in what ways.

Thanks again.

[Dan N]

Very cool! Thanks!

I always wondered about the timeline for the Univibe, Resley Tone, Vibra Chorus. The transistor choices make this look like the last incarnation.

Thanks again for the trace!

[Fret Wire]

Awesome trace Clay