To keep a long story short, I wired a pair of computer speakers (Walmart brand) directly to the Pedalshield. They were of poor quality, and contain a 4863 amplifier chip. The first attempt simply fried the 4863 chip after a few minutes of playing (smelly smoke ).
I investigated with a second set of speakers of higher quality (Logitech), and the same situation develops. The 4863 chip gets very hot, only when playing, with the gain turned up past about 40%.
Is it possible to output unamplified/line level from the Pedalshield? So I don't keep frying speakers?
Hi there, pedalSHIELD output is not particularly high, but its true that is not line level... a bit over it.
If you want to reduce to level ar the output of the pedal this is the best way:
- If you look at the
schematic
, the last op-amp is a summing amplifier (it adds the original guitar signal that comes trough R15 and the modified signal that comes trough R16).
- The
Summing Amplifiers
output is Vout = Rout/Rin (V1+V2) where Rout=R17=100K, Rin=R15=R16=100K, V1= original signal, V2=modified signal.
So the output voltage of the pedal Vout = 100K/100K(V1+V2), if you want to reduce the output voltage just reduce the value of Rout=R17
In a nutshell: If you want an output voltage half the size make R17= 47K, or even lower 22K.