Adding an effects loop to a Classic 20

[Nalo1022]

HI been nlurking the boards here for a bit but never posted. I just recently picked up a Peavey Classic 20 and I love it, but I want to add an effects loop. After scanning the schematic I have a good idea of where to make the break foir the loop and it works very well with the layout of the pcb but there are a few things that i need some help with. I know there will need to be a buffer of some type in there and i was going to try to keep that as simple as possible so it could be assembled on a daughter board, so i decided to make it solid state and was wondering if something like this would be suitable as i already have one of these made up and laying around http://aronnelson.com/gallery/Groove...rbuffer?full=1. I fthis is usable where would eba safe place to tap off 9v?. Would there be any problems running this in paralell with the current circuit and adding a blend for the dry and wet?

[Enzo]

Or add it between the treble and the MV. The main question is - what is the signal level at that point in the circuit? If it is about a volt, then there you are, just add some jacks. If it is 30 volts, then the send has to be padded down and the return amplified back up to the 30v.

Get the CLassic 30 schematic and see how they handled it there.

[Nalo1022]

actually I did look at the classic 30 schem and it appears to be going through a buffer type circuit.but heres the snippet from the effects loop circuit and it cuts in at the same spot. The full schematic is at www.blueguitar.org/schem . The mps6534 is a general purpose amplifier. You can find the datasheet here http://www.fairchildsemi.com/ds/MP/MPS6534.pdf . If none of this helps you looks like Im have to bust out the multimeter.

[Enzo]

I am already familiar with the C30, I just have no idea how much signal is at the break point in your 20, so do indeed get out the meter and find out. It means teh difference between a simple pair of jacks and extra circuitry. The similarity between the amps is the reason for the suggested comparison.

[JazznBlooz]

I also have a Peavey Classic 20 that needs an fx loop added.

How didi this turn out?

[Enzo]

Get out your meter and.....