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EHX Bass Micro Synth - DIY True Bypass Mod
- Thread starter EricF
- Start date
yeah I meant I don't like it because I guessed wrong
Oh.
I was wondeirng how come there was still an effected signal if i did guess wrongly. Was looking at the blog link you posted also, and i couldn't figure out what was going on there, and the last part, the guy only connected the input to the board using the crocodile clip wire. (the yellow wire to the board that was originally connected to the input jack. =)
just letting everyone know that I rewired my BMS according to itzs's picture, and it worked great! the bypass difference is impressive...
Well, I am not a bass player, but I do LOVE my Bass Micro Synth for my guitar. I modded it from the guitar MS. It's AWESOME!!!
Yesterday I finished my Expression Pedal mod to control the Stop Freq slider.
I see a lot of people trying to do this, and though many have done it somewhat succesfully. Noone has actually, completely done it correctly. I mean this to be helpful, NOT, Look at me, I'm the best, LOL!
I used a TRS 1/4" phone jack, with DPDT switching capabilities. This jack actually came with my L.R. Baggs Control X piezo mixer that I put into one of my 7-strings. There are 9 pins on this amazing little 1/4" phone jack.
The mod requires 5 wires from the jack to the PCB, and three traces that must be cut.
The cut traces are - 10V, and two Ground traces. The first ground trace to be cut is the one between the Start and Stop freq faders. Now on the other side, (the right side, not the bottom) there is a small ground trace goinf off to a resistor. This too, must be cut and replaced with a jumper from the resistor back to the ground of the Start Freq fader.
The -10V supply goes to the common terminal of one pole of the switch. (Wire #1)
Ground goes to the common terminal of the pole on the switch. (Wire #2)
On the normally closed side of the -10V pole, we want the -10V to be connected to the top of the Original EH fader. (Wire #3)
On the normally closed side of the Ground pole, we want the Ground to be connected to the bottom of the Original EH fader. (Wire #4)
On the normally open side of the -10V pole, we want the -10V to be connected to the outside lug of our Volume Pedal pot. Which side only matters to control which direction of pedal travel will be the High end of the sweep.
On the normally open side of the Ground pole, we want the Ground to be connected to the other side of the Volume Pedal pot.
With the VP cable removed the Normally Closed contacts complete the connections from -10V and Ground to the top and bottom of the Original Fader, respectively.
With the VP cable inserted the Normally Open contacts complete the connections from the -10V and Ground to the outer lug on our Volume Pedal pot.
I chose the leave the wipers of the two pots conected. Because the 'unused pot has no Voltage, or Current because both ends are open. This way the unused pot is completely removed from the Voltage and Ground. Without Voltage and ground it is virtually removed from the circuit. I say virtually because it is still connected by the pots wiper (the middle lug). (Wire #5)
I have my notes, and detailed drawings that I will post soon. I just wanted to get this out there for those who are unclear on the completion of the mod. I'm always searching for help in performing special mods. When I can't find help I figure out on my own, and post it for those who need it.
I hope you enjoy.
Mike Dunn
Yesterday I finished my Expression Pedal mod to control the Stop Freq slider.
I see a lot of people trying to do this, and though many have done it somewhat succesfully. Noone has actually, completely done it correctly. I mean this to be helpful, NOT, Look at me, I'm the best, LOL!
I used a TRS 1/4" phone jack, with DPDT switching capabilities. This jack actually came with my L.R. Baggs Control X piezo mixer that I put into one of my 7-strings. There are 9 pins on this amazing little 1/4" phone jack.
The mod requires 5 wires from the jack to the PCB, and three traces that must be cut.
The cut traces are - 10V, and two Ground traces. The first ground trace to be cut is the one between the Start and Stop freq faders. Now on the other side, (the right side, not the bottom) there is a small ground trace goinf off to a resistor. This too, must be cut and replaced with a jumper from the resistor back to the ground of the Start Freq fader.
The -10V supply goes to the common terminal of one pole of the switch. (Wire #1)
Ground goes to the common terminal of the pole on the switch. (Wire #2)
On the normally closed side of the -10V pole, we want the -10V to be connected to the top of the Original EH fader. (Wire #3)
On the normally closed side of the Ground pole, we want the Ground to be connected to the bottom of the Original EH fader. (Wire #4)
On the normally open side of the -10V pole, we want the -10V to be connected to the outside lug of our Volume Pedal pot. Which side only matters to control which direction of pedal travel will be the High end of the sweep.
On the normally open side of the Ground pole, we want the Ground to be connected to the other side of the Volume Pedal pot.
With the VP cable removed the Normally Closed contacts complete the connections from -10V and Ground to the top and bottom of the Original Fader, respectively.
With the VP cable inserted the Normally Open contacts complete the connections from the -10V and Ground to the outer lug on our Volume Pedal pot.
I chose the leave the wipers of the two pots conected. Because the 'unused pot has no Voltage, or Current because both ends are open. This way the unused pot is completely removed from the Voltage and Ground. Without Voltage and ground it is virtually removed from the circuit. I say virtually because it is still connected by the pots wiper (the middle lug). (Wire #5)
I have my notes, and detailed drawings that I will post soon. I just wanted to get this out there for those who are unclear on the completion of the mod. I'm always searching for help in performing special mods. When I can't find help I figure out on my own, and post it for those who need it.
I hope you enjoy.
Mike Dunn
How would you rate this on difficulty from 1-10 as a project. I'm a beginner but would like to learn.
Thanks, mike.
There's another recent thread out there regarding the expression mod. The other methods are a little less invasive, but may or may not be as effective (no pun intended). I haven't had time to try either method out yet.
I would like to see some detailed pics of your mod, including what components you used. What potentiometer value did you use in your exp pedal?
Col Monk
There's another recent thread out there regarding the expression mod. The other methods are a little less invasive, but may or may not be as effective (no pun intended). I haven't had time to try either method out yet.
I would like to see some detailed pics of your mod, including what components you used. What potentiometer value did you use in your exp pedal?
Col Monk
The other thread, with the alternate methods.
For instance, it appears that your method requires that your remove the plug from the socket in order to restore normal operation. My method gives you a mini-toggle switch to select whether you want exp. control or normal, envelope control.
"Correctly" is subjective!
For instance, it appears that your method requires that your remove the plug from the socket in order to restore normal operation. My method gives you a mini-toggle switch to select whether you want exp. control or normal, envelope control.
Just want to be clear on a couple things from the pic (referenced below) before I go ahead and do this today to my BMS...
In the picture...
- The Grey wire coming off the top middle post of the 3PDT switch goes to the Output hot?
- The Purple wire that was previously the Output hot connects to the bridged ground of the Input and Output, and grounds to the chassis cover?
Any confirmation/clarification would be appreciated!
Thanks,
c
ok. from top to bottom, left to right. this is how i did it.
|Brown from PCB | Grey to Hot of Output Jack | Black to Bottom Right|
|Black From LED | Blue to Ground (chasis) | Empty|
|Red (to Yellow) to PCB | White to Hot of Input Jack |Black from top right|
Hope its clear. =)
I'm dying to do this mod but don't feel as if I am experienced enough to dice with the pedal. I know that some people have tried to make an easy walkthrough but I'm still confused. I can't really make out what's going on.
I would be grateful if someone would be good enough to do an idiots guide and describe every little alteration step by step fashion? Don't worry about being patronising - i don't even know what the output "hot" is?
I love this pedal but the tonesuck means I can't use it live.
I would be grateful if someone would be good enough to do an idiots guide and describe every little alteration step by step fashion? Don't worry about being patronising - i don't even know what the output "hot" is?
I love this pedal but the tonesuck means I can't use it live.
If you think it might be a bit more than you can handle, why not put the pedal into a bypass loop? Pick up a Keeley looper or for half the cost go to Loop-master.com and get a single bypass loop.
Yeah, I've considered this and that's my plan B. I'm not bad with the old soldering iron and was set to do this mod last night but when I opened the back of the synth up and took a peek around I felt that I couldn't tell exactly what's going on from the previous posts and diagrams and didn't want to destroy the pedal.
Howdy All
I finally got around to re-wiring my BMS yesterday using itzs' picture and description. It worked a treat.
Only difference is that I didn't add the extra ground wire -- I just split the ground to the LED and add some wire to it to make the connection.
I'm looking forward to hearing the difference in my bass signal without that shoddy bypass sucking tone.
Still haven't added the exp pedal jack for the stop freq slider - but if I decide not to get the newer smaller version I probably will at some point.
Monk
I finally got around to re-wiring my BMS yesterday using itzs' picture and description. It worked a treat.
Only difference is that I didn't add the extra ground wire -- I just split the ground to the LED and add some wire to it to make the connection.
I'm looking forward to hearing the difference in my bass signal without that shoddy bypass sucking tone.
Still haven't added the exp pedal jack for the stop freq slider - but if I decide not to get the newer smaller version I probably will at some point.
Monk
