freestompboxes.org

Hello friends from around the World
Time for a new DIY project - this time it's an ABY selector ( see if you can guess where the inspiration for this one came from). The selector is totally noiseless in switching hence it is called the Silent Selector!
It continues my love of optocoupling devices, and many of you will no doubt find other uses for this circuit - loop selectors and guitar amp channel switchers come to mind
this circuit uses a CMOS 4069 Hex Inverting buffer IC in a very novel dual flip flop arrangement - analogguru will love this
It is important to use momentary footswitches - I could only find cheap plastic switches locally, but obviously metal ones would be preferable in a stage environment. I used green indicator LEDs - no mojo here
Also the layout shows a 78L09 regulator IC - I used a 7809 type because that is all I had in my parts box The regulator is really only for overvoltage protection in this circuit. The schematic is worthy of analysis - feel free to ask any questions - I will do my best to answer them.
Okay here we go again!!!
ENJOY

Corrected schematic:
BAJA Silent Selector - enclosure label
BAJA Silent Selector PCB
BAJA Silent Selector Overlay
BAJA Silent Selector Label







PS: thanks to our member oscarv77 who posted the gut shot pictures that inspired the creation of this project
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Very interesting bajaman.

I suppose if the "combine" funtion is not needed, the optocouplers can be driven directy by a switch without the CMOS logic.

Another way to expand the concept on multiple channels (or even MIDI controlled!) would be using a programmable controller like the Arduino.

bajaman wrote:Hello friends from around the World
Time for a new DIY project - this time it's an ABY selector ( see if you can guess where the inspiration for this one came from). The selector is totally noiseless in switching hence it is called the Silent Selector!
It continues my love of optocoupling devices, and many of you will no doubt find other uses for this circuit - loop selectors and guitar amp channel switchers come to mind
this circuit uses a CMOS 4069 Hex Inverting buffer IC in a very novel dual flip flop arrangement - analogguru will love this
It is important to use momentary footswitches - I could only find cheap plastic switches locally, but obviously metal ones would be preferable in a stage environment. I used green indicator LEDs - no mojo here
Also the layout shows a 78L09 regulator IC - I used a 7809 type because that is all I had in my parts box The regulator is really only for overvoltage protection in this circuit. The schematic is worthy of analysis - feel free to ask any questions - I will do my best to answer them.
Okay here we go again!!!
ENJOY

members/bajaman/Baja/BAJA%20Silent%20Se ... CF0004.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... CF0005.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... CF0006.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... CF0010.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... ematic.png
members/bajaman/Baja/BAJA%20Silent%20Se ... lector.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... %20PCB.png
members/bajaman/Baja/BAJA%20Silent%20Se ... verlay.png
members/bajaman/Baja/BAJA%20Silent%20Se ... 0Label.png

PS: thanks to our member oscarv77 who posted the gut shot pictures that inspired the creation of this project

Woohoo! excellent job, Baja!

PS: just upgraded two of the pictures (DSFC0005 and DSCF0010)
I did not have my digital camera set to macro
cheers
bajaman

bajaman wrote:PS: just upgraded two of the pictures (DSFC0005 and DSCF0010)
I did not have my digital camera set to macro
cheers
bajaman

what dpi should i print the pcb at?

oh, and also NICE WORK!

MAN, that's a lot of diodes...

Hi Patrick

MAN, that's a lot of diodes

and not one is being used to clip the signal

the PCB is 1200dpi the scale is in tenths of an inch.
cheers
Steve

bajaman wrote:Hi Patrick

MAN, that's a lot of diodes

and not one is being used to clip the signal

the PCB is 1200dpi the scale is in tenths of an inch.
cheers
Steve

yeah i think i got it. i printed it with a vertical dimension of 2.4 inches and my eyeball says it looks okay, but i will have to wait until i get home to see (i'm at work)

if it works out okay i'm going to tie one of the outputs to a buff n blend to have a switchable blendable effects loop!

Hmm, nice vintage digital electronics 'round here
First some homemade static RAM cells, then Diode-Resistor-Logic ...

I'll post soon in "Pimp my cheap Pedal" a mod of the Behringer AB200 (dual relay-based A/B switch, also sporting a 4069 as memory) to use it as a loop swapper, so you can have the wah before OR after the fuzz.

For momentary footswitches, check this thread
I also moved the untested (?) passive variation on the BSS by Silent Fly into a separate thread. Do have a look.

thanks

bajaman wrote:Hello friends from around the World
Time for a new DIY project - this time it's an ABY selector ( see if you can guess where the inspiration for this one came from). The selector is totally noiseless in switching hence it is called the Silent Selector!
It continues my love of optocoupling devices, and many of you will no doubt find other uses for this circuit - loop selectors and guitar amp channel switchers come to mind
this circuit uses a CMOS 4069 Hex Inverting buffer IC in a very novel dual flip flop arrangement - analogguru will love this
It is important to use momentary footswitches - I could only find cheap plastic switches locally, but obviously metal ones would be preferable in a stage environment. I used green indicator LEDs - no mojo here
Also the layout shows a 78L09 regulator IC - I used a 7809 type because that is all I had in my parts box The regulator is really only for overvoltage protection in this circuit. The schematic is worthy of analysis - feel free to ask any questions - I will do my best to answer them.
Okay here we go again!!!
ENJOY

members/bajaman/Baja/BAJA%20Silent%20Se ... CF0004.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... CF0005.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... CF0006.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... CF0010.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... ematic.png
members/bajaman/Baja/BAJA%20Silent%20Se ... lector.jpg
members/bajaman/Baja/BAJA%20Silent%20Se ... %20PCB.png
members/bajaman/Baja/BAJA%20Silent%20Se ... verlay.png
members/bajaman/Baja/BAJA%20Silent%20Se ... 0Label.png

PS: thanks to our member oscarv77 who posted the gut shot pictures that inspired the creation of this project

okay, some questions:
1) i'm sure i know the answer based on another thread, but the "+" on the diodes actually refers to the cathode, or black band of the diodes, correct?
2) if the 78L09 is just for overvoltage protection, would you leave it out if you didn't want it or would you have to jumper something?
3) on the 2.2 "BP" caps (i assume that means bipolar) all i have are polarized, are the non-polarized necessary due to the design or could i sub in polarized? and if i can sub them, which way would they be oriented? THanks!

1 - yes
2 - yes - you have to jumper between pins 1 and 3 if left out - make sure you have regulated 9v dc supply though or battery.
3 - use non polar or bi polar caps not polarised caps - you could also use 2.2uf poly film caps here.
cheers
bajaman

bajaman wrote:1 - yes
2 - yes - you have to jumper between pins 1 and 3 if left out - make sure you have regulated 9v dc supply though or battery.
3 - use non polar or bi polar caps not polarised caps - you could also use 2.2uf poly film caps here.
cheers
bajaman

hmm, might have to make an order. i don't have anything that large in poly or metal film, and even if i did i don't think i could squeeze them on the board

i will jumper those then, i don't have any 7809's on hand (only 7812 and 7805, would 7812 work?), but once i get some more i will remove the jumper and do it that way.i apologize, after i posted i looked at your build pics and realized that the band markings are quite clear...

is the 5088 part of a buffer? i'm thinking of using this as a switcher for an outboard tape echo so that i can switch the guitar signal from the tape echo to bypass, but leaving the output of the echo in line so i can have delay tails. for this, i want to make sure i have a decent buffer on the output. I'm thinking something like this:

output A ------>buffer input jack 1 -----> common buffer output jack
output B ------>tape echo input -----> tape echo output ---->buffer input jack 2 -----> common buffer output jack

would this work? i think it would, as when you switch to output B, you are going to the tape echo, then you switch to output A and the tape echo output would still be going, but you would stop feeding it input. thoughts?

one more question baja, could any photocoupler, even homemade, work in place of the vtl5c9? They are awfully expensive...

one more question baja, could any photocoupler, even homemade, work in place of the vtl5c9?

Hi Patrick
yes - i rolled my own successfully - absolutely noiseless switching - very versatile and clever circuit
cheers
bajaman

bajaman wrote:

one more question baja, could any photocoupler, even homemade, work in place of the vtl5c9?

Hi Patrick
yes - i rolled my own successfully - absolutely noiseless switching - very versatile and clever circuit
cheers
bajaman

great, i have a few nsl32's around. I'll try them. I'm excited, I have all the circuit built except those pesky photocouplers.

so i finally got it all built using roll-your-own photocouplers. I used these LEDs:

http://www.smallbearelec.com/Detail.bok ... s=9ba4a822

and these LDRs (the 8002 part):

http://www.smallbearelec.com/Detail.bok ... s=9ba4a822

First I fired it up and the CMOS got SMOOOOKING hot! realized i had it in backwards. Assuming it was fried, I replaced it with a new one. But I can't get either of the LEDs to light up. I just plugged it in without input on it or anything, just trying to validate my switching. I will wire up the input jack and get an audio test, but for right now it looks like my build is non-functioning

Are there any other parts that i could have fried by putting the 4069 in backwards?

post some pictures - then we can help you
bajaman

bajaman wrote:post some pictures - then we can help you
bajaman

will do, my camera was locked away last night but when i get home today i will take some pics and post. thanks!

As promised...

one thing I can see straight away - the extreme right diode is the wrong way around.
bajaman