The Colonels Buffer -special order

Danny1969

I was asked to build this by a band member who plays acoustic and electric,  and has a hatred of unplugging cables and cables running across the stage. All cables from tuner \ footswitch have to go along the front of the stage and down the side then along the back. This is fine but the loss of signal from a passive electric guitar along 10 metres of even good quality cable is dramatic. Likewise one of his acoustics which has a basic ok pickup but no preamp and is very loaded by the length of cable. 

So design spec was :

Need to run 10 metres of cable with no treble loss
Electric and acoustic need need to output to same tuner
Needs to be able to feed tuner DC power
Turning on acoustic needs to mute electric and vice versa
Needs mute everything switch for singing only songs 
Needs to have switch on electric channel that simulates rolling back guitar volume to clean up amp but with no treble loss 

So I worked out the basic switching using dual colour LED's to show status of footswitchs. Then worked out the best placement of sockets and switchs and drilled the box 



Then draw up a basic regulated power supply and a couple of basic buffers ... nothing special just bog standard non inverting 100% negative feedback opamp config .... with the electric version driving into a 10K pot which is defeated by the boost footswitch. 



Then build the circuit 



And then wire it all together, print some dodgy graphics and here it is 





All working correctly in the workshop but first gig will be on Sat, along with the custom multicore I'm making for it 

Winny_Pooh

Nice work

Gagaryn

Very clever.

SteveF

That's great.