Arion SCH-1 Chorus/Vibe mod plus true bypass

[taddy666]

Couldn't find any info on this on the web so I attempted it myself based on some instructions for modding the SCH-Z model. It works really well. Here's the schematic i used

http://www.hobby-hour.com/electronics/s/arion-sch1-chorus.php

and here's my mod

http://s1329.photobucket.com/user/taddy666/library/SCH-1%20mod?sort=3&page=1

Basically you rewire the DIRECT/STEREO switch so that is now acting as a connect/disconnect switch between pin 1 of IC1 and the R30/31 junction. So when it is open circuit you are basically cutting the dry signal path giving that warbly/vibrato sound.
So you need to remove w3, run R38 and R40 junction direct to your 3PDT switch, cut the track from C4/R6 junction to the DIRECT/STEREO switch and insert the 3pdt between the input socket and R1. The flip-flop circuit (IC6) defaults to off so you need to connect R53 to the output of pin 1 (9V at default) and the removed R54 terminal you can wire to the 3pdt. Connect an earth when the circuit is activated as this will turn the LED on because it is fed 9v from the other end. Only output B will work with this configuration (the socket nearest the pots).
Hope that make sense.

Any questions just ask. Good luck!

[archimedes]

Thanks for this information

I just got mine yesterday and the higher rate  is a really unique sound, quite Leslie like as so often reported and one that brings a smile to my face, this is primarily what I bought the pedal for. Not too keen on the slower rate, lower depth settings for slow swirling sounds, a little too flanger-like so I may look at trying to adjust the delay time as detailed in another post in this forum. Also I would like to tweak the slight volume boost  a little and possibly try the vibe mod. All of this sounds like I don't like pedal, I do very much for that fast setting, it's definitely a keeper since no other chorus sounds quite like it but would like to open up the scope little more.

Regarding fitting the 3PDT switch, there seems to be a kind of plastic cylinder shape moulded as part of the underside of the treadle, did you have any problems with this when drilling? I am not going to rush into TBP but I'll want to do it at some point

Thanks

p.s. If I do modify the delay time it will have to be switchable as it would be daft to lose the unique quality if the fast settings!

[jazzguitarist]

Thanks to taddy666, I did my own modification to make the true bypass on the Arion SCH-1.

I did not cut the circuit or make any other mod except the true bypass.

This is my schematic.

http://www.suonoelettronico.com/arion_chorus_sch1_schemaelettrico_truebypass.html

It works perfectly.

All the best !