line level pedal

[turing]

is there an easy way to mod guitar pedals to take line levels? i had my anderton filter, rebote delay, and small stone patched as inserts on my desk, and while the filter was fine, the delay and phaser were massively overdriven. but then the filter handled guitar level with no trouble.

my (uneducated) guess would be to increase the first resistor frrom the input. but it took such a lot of sweat to get these things working in the first place i'd be very grateful if someone could give me the definitive answer.
much obliged.

[Paul Perry (Frostwave)]

If it was me, I'd just make a voltage divider from two resistors:

line signal goes to a 100K resistor , the other end of the resistor goes to a 10K resistor then the other end of the 10K goes to ground.
And you take the reduced signal from the junction of the two resistors.
Change the 10K to vary the amount of loss. (smaller = less output).

You can build the whole thing inside a plug, so you can have a magic "line to guitar" converter lead.

[puretube]

make-up gain afterwards? (e.g. LPB2 - like...)  :?

[turing]

thanks guys, i think i'll try the voltage divider, with a switch to flip it back to guitar level if needed.
wouldn't the booster add more distortion? i mean the signal was overdriven anyway.
so does this resistor junction come straight off the input signal to the pcb?

[Paul Perry (Frostwave)]

The resistor junction just goes where the input went originally.
The ground connection stays the same, but wiht the 10K (or whatever) connected to it.

The idea of a make up booster afterwards, as puretube suggests, is to have a (non-distorting) amplifying stage after the effect, to get the output ip to line level. But, depending on what you are doing, you may not need line level out, your mixer or whatever may have enough gain.

[R.G.]

Line levels are about a factor of 10 (20db) bigger than guitar outputs on average. So to keep a guitar pedal doing what it's doing, you need to attenuate line level by about 10:1, run through the pedals, then amplify back up by 10:1. Your pedals may or may not have enough follow up boost to do this. If they do, you might get by with a resistive divider. If they don't, you'll need another booster to get the level back.

In general, check at GEO first. In this case, you might want to use the Adjusticator. It's designed to specifically this kind of level matching.