I currently play through a peavey classic 30 combo, and it seems like the second channel (gain channel) won't give me a boost when i use my OD-3 with the level all the way up, and the gain all the way down. I often play with a lot of gain from the amp, and then i like to give myself a boost for the lead-parts to cut through the mix when playing with my band.

To compare, when doing the same thing on the clean channel, the OD-pedal gives me a boost. In other words it works.

Does te classic 30 have a lot of compression or something on the gain-channel? Or will getting an eq-pedal do the job? I would think not seeing as the OD should work in the first place. My uncle, who is a guitar tech says that it is possible to use the OD-pedal in the ex-loop, and then it might give me a boost. He suggests that there might be something wrong with the amp, something that wouldn't surprise me. I've had some trouble with it in the past.

What do you think?
The level boost drives the tubes more, causing more gain. If it works on the clean channel it means that you have enough headroom to keep the sound clean even when boosting the signal, causing a volume boost. If you want to add more volume, then put it into the effects loop.
^ what he said

All gain is is turning up the volume a lot so it causes the tubes to distort. If you turn up the volume going into the clean channel, where there is no distortion, you get a volume boost. If you turn up the volume going into the gain channel, it just turns up the gain and gives more distortion, not volume. If you put the OD-3 in the FX loop, after the distortion, you will get a volume boost on both channels.
The reason I'm asking so may questions instead of trying it myself is because I don't have the opportunity at the moment. So as soon as I can I'll try it through the ex-loop. What you say makes sense, but it does increase the amount of gain on the clean channel, not just the volume. Don't know if that changes anything, just thought I'd mention it. Any other theories as to way it doesn't work when placed in front of the amp on the gain-channel? Isn't it commonly known that it should?

Edit: I guess you guys answered my question already, so thanks One last thing though, will using the pedal in the loop rather than in front of the amp make it sound a lot different? If I am to solely use it as an OD for another time/song, will I have to put it back in front of the amp again?
Last edited by Simon4392 at Dec 21, 2008,
Yes, it doesn't work if you try to add gain from your fx-loop. It may work, but it won't sound good.

If you're going to buy two OD pedals, one for the loop, and another in front of the amp, go for an OD in front of the amp and an EQ pedal in the loop. It allows to do more than just boost it.
Get an EQ and stick it in the loop, boost the mid frequencies, but not much otherwise it'll give you a sort of half cocked wah sound. The trick is to find the right balance between cutting through the mix and keeping the right tone.