Boss CH-1 (Digital Version) Mods

Ah the downtrodden Boss CH-1.  It was a exciting pre-show purchase for me a 20 something circa winter 2003.  Having grown up on a healthy dose of lush chorus from Nirvana to The Police, I was looking to recreate those tones.  I'm sure my heart was set on a Electro Harmonix Small Clone or Poly Chorus, but the lowly Guitar Center at the time only had the Boss.  It did the job, but as time went on (17 years now), as I read the bashing of it on various guitar forums, and as I played friends' Poly Choruses, I realized the damn thing didn't do all I wanted it to.  I wanted the wacky quick modulation.  

First mod attempt

I found some great mods online for altering the delay time from flanger to more extreme chorus by changing 47pf cap on the C10 cap to a lower or higher value, up to 100pf.  Unfortunately, upon opening my chorus (bought in 2003) I realized it was made of all surface mount components, which are a bitch to try to mod (not recommended).  Not only that, but upon close inspection, I realized the whole circuit is different with a very different chip powering the delay.  They really should have just named my pedal a CH-2 or something.  After a lot of searching and research, it turns out Boss' schematic refers to it as a CH-1T(Taiwan?).  It really helps when trying to search for it.  I guess Boss decided to go with the new layout sometime after 2001.  That said, I'm not sure I really hear much differences in the old to new models.  But the old analog mods will not work on this newer model.  So after more searching I came across a great blog that had a newer digital mod. Here:  https://proto-schlock.blogspot.com/2013/04/boss-ch-1-mod-digital-version.html?m=1

Here's the new schematic in case you can't find it.

This guy changed the value or the R63 resistor to around 1.8K.  He also had some other interesting mods which I will get into later.  I didn't want to be too invasive to my pedal, so I opted to add a 8.2K resistor in parallel to the original 15K to cut the total resistance value to around 5.3K. Worked great!  Wacky quick modulation galore!  However, I got greedy and tried poking around at the circuit to find what controlled the delay time on the chip.  I had some luck with the R43 resistor, but dropped the pedal in doing so.  The modded, very small resistor pictured above snapped off.  Upon many failed attempts, I finally settled on bridging the connection for 0 resistance.  I got even quicker modulation up to 99% of the rate control knob.  However it folds in on itself at the very last 1% maxed position to cancel out the movement.

So, here's the disclaimer* DON'T TRY TO MOD THESE SUPER SMALL COMPONENTS UNLESS YOU'RE WILLING TO DESTROY YOUR PEDAL OR UNLESS YOU HAVE THE PROPER TOOLS AND SKILLS.  Seriously this was a pain to mod.  I think bridging the resistor ended up being easier in the end.  Maybe next time just a small dab of solder over the resistor.

Now another mod I see a lot of people attempt is adding vibrato to a chorus pedal.  They are in fact the same circuits but with chorus, it adds the dry guitar signal.  Where as vibrato is just the modulated signal only.  So, if you have a stereo chorus (two outputs) like my CH-1, usually you can just add a jack plug connected to nothing into the output B or second output (usually) This will make the pedal send the second output dry signal to nothing.  Muting it, turning your main output to the amp into vibrato.  Hope this helps some people!  If anyone figures out a safe why to mod the delay time to flanging and deeper chorus, let me know.  Here's a quick video sample. (of the earlier mod plus vibrato)

Best Volume Pedal Mods and Hacks

I know, volume pedals.  Boring right?  I used to only use them with lap steel or volume swells when I was younger.  And most my volume swells could have been done with the volume control on my guitar.  So I never pulled the pedal out much for a long period of time.  I think a lot of people are the same way,  That was until I started playing more dynamic music with a lot more volume changes and had a real need for quick control over my distortion vs clean sound.  The full on/off distortion control I got from my amp switcher or pedals wasn't cutting it anymore for the music I was playing.  I also started loving the clean sound of a driven amp with my volume control down.  With my hands busy playing I couldn't make the changes I wanted on the guitar quick enough, so I turned to my old volume pedal to control my gain with my foot.  Only problem was it was hard to get the pedal to turn down to where I needed it to be for a clean sound and not cutting my volume off completely.  Update* I did the same thing electronically which is a much better mod. 

Heightened Rubber Door Stop

A new minimal heel position for my "clean channel"

Solution:  A shaved down rubber door stop from a hardware store at the heel of the foot control.  There just happens to be a small rubber stop with a set screw there already on the Ernie Ball volume pedal.  If you replace that stopper with something a bit higher you can disable the pedal from turning the volume fully off.  Just find the clean tone position you want and measure the height to shave down your door stopper at.  This really makes for easier changes in a live situation.  Everything from distorting to clean all at your control, and no worries of cutting off your volume completely.

Treble Bleed Mods

Next up: Playing clean tone with a standard wired volume pot turned down leads to another potentially unwanted problem.  Just like with your guitar's volume control, you loose treble as the pot is turned down.  I decided with the way I was using my volume pedal, I would have to do a treble bleed mod.  There are a few versions of the mod to the right.  The best resource online is from JohnH on this board site: http://guitarnuts2.proboards.com/thread/5317/treble-bleed-circuit
There you will find all the EQ curves at different decibels with all the possible treble bleed mods, best component values and a improved circuit with a stacked dual concentric pot.  For most of my needs I find the parallel mod does a good enough job retaining the EQ curve across different volumes.  If you do end up doing this mod, you will need help putting the pedal it back together with it's string and string pulley. It's not as easy as it looks.  Plenty of tutorials on youtube to help you with that. https://www.youtube.com/watch?v=rrDRKahbY28

Volume Pedal Turned Expression Pedal

The Final Hack: Not a mod, but a use for a standard PASSIVE volume pedal that isn't well know.  Instead of buying an extra expression pedal many companies make for their pedals, you can use a volume pedal with a Y cable with a stereo jack plug.  Just plug the mono jack plugs(Y part) into the volume pedal's input and output, and the stereo jack plug(single tail part of the Y) into the expression jack.  You may have to switch the input and output jacks around if it doesn't work on the first try,  You could also double up or triple up the one pedal to control many different expression controls.  Just use an all female input headphone splitter adapter to run two stereo chords out to different pedals expression inputs.  Or multiply the expression control with more adapters if you want.

So, lots of things you can used a volume pedal for.  So don't overlook them.  Surprisingly it's has become the most essential part of my rig for controlling how much gain I'm getting from my amp.  Probably the most essential part of how my guitar playing works in my three piece band.  These tips and mods aren't all you can do either.  Control the amount of a direct effect in a wet/dry amp setup.  Perhaps make synth like pad sounds with a delay like David Gilmour's sound on sound setup.  http://www.gilmourish.com/?p=287

Experiment.  Have fun.