Pauleo1214
Well-known member
- Build Rating
- 4.00 star(s)
I just finished a guitar for a customer in Florida. It was a fun build and it plays like a dream but boy were the electronics a pain!
It was simple enough until it fubar and I had to pinpoint the issue which was not obvious. Everything is controlled by 8 knobs. They are,
First row
1. Master volume
2. Neck/ Bridge pickup pan
3. Middle pickup blend
4. Magnetic/ piezo pan
Second row
1. Magnetic tone
2. Master treble
3. Master midrange
4. Master bass
I used a Fishman Powerchip as a preamp/ blend for the piezo and magnetic signal. A Box of all EQ was at the tail end of it.
I wired it all up and only got the magnetic signal. A thorough visual inspection revealed no obvious issues. I then found out the tip and ring pads were reversed on the pcb which came that way from Fishman. Upon further testing it, it only worked to blend in the piezo and not pan between magnetic and piezo signals. So out went the Fishman power chip.
The Box of All didn't work either. Fortunately this was a lot easier to diagnose. I knew I was getting 9V from the battery but a quick measure of the circuit protection diode revealed a sever in the trace. The next problem was a bad 250k pot on the treble control.
To fix the piezo panning problem, I wired a GPCB Stage 3 Boost for the L.R. Baggs Bridge. I wired up a Buff n Blend for the magnetic signal and inserted the boost at the return end of the loop, bam, instant panning.
Due to all the pots needing to be wired offboard and the circuits hidden out of view from the bottom f-hole, a spaghetti mess could not be avoided. With all that said here are some messy gut shots and photos of the guitar itself. Cheers!
It was simple enough until it fubar and I had to pinpoint the issue which was not obvious. Everything is controlled by 8 knobs. They are,
First row
1. Master volume
2. Neck/ Bridge pickup pan
3. Middle pickup blend
4. Magnetic/ piezo pan
Second row
1. Magnetic tone
2. Master treble
3. Master midrange
4. Master bass
I used a Fishman Powerchip as a preamp/ blend for the piezo and magnetic signal. A Box of all EQ was at the tail end of it.
I wired it all up and only got the magnetic signal. A thorough visual inspection revealed no obvious issues. I then found out the tip and ring pads were reversed on the pcb which came that way from Fishman. Upon further testing it, it only worked to blend in the piezo and not pan between magnetic and piezo signals. So out went the Fishman power chip.
The Box of All didn't work either. Fortunately this was a lot easier to diagnose. I knew I was getting 9V from the battery but a quick measure of the circuit protection diode revealed a sever in the trace. The next problem was a bad 250k pot on the treble control.
To fix the piezo panning problem, I wired a GPCB Stage 3 Boost for the L.R. Baggs Bridge. I wired up a Buff n Blend for the magnetic signal and inserted the boost at the return end of the loop, bam, instant panning.
Due to all the pots needing to be wired offboard and the circuits hidden out of view from the bottom f-hole, a spaghetti mess could not be avoided. With all that said here are some messy gut shots and photos of the guitar itself. Cheers!