So you shouldn't use a guitar amp?

Ok, I bought the stuff and tried it. It doesn't work. It reduces the signal so much that I have to turn the amp all the way up to hear anything at all, and it's not loud enough to be useful at that.

Thanks Tom,

Great effort & feedback on that cable. I was suspicious that it might not work.

Some theremins use a pot to adjust the line output level down to match the input level of any amplifier input.

This would be a good project for someone with a musical circuit webpage to create.

“Make this simple $5 cable for connecting a line level output into a guitar amplifier's input.”


Christopher

I use a cheap solid-state guitar amp with my PAIA Theremax and I find no problem whatsoever with the strength of the signal. But one point made is absolutely true: the better the amp, the better the sound. Any electronics expert will tell you, you can have the finest theremin in the world, it is only as good as the amplified loudspeaker system that is your output. The sad fact of quality musical instruments is that they do tend to cost money. The sad fact of most theremins is that they require an amplified loudspeaker to make sound.

I have been using a Fender M-80 guitar amp. It has 2x10" speakers in it. A friend gave it to me and it works fine but it is heavy as hell and I wanted something more portable. So, last week I bought a Vox Valvetronix 30 watt amp. It came with lots of cool sounding effects and was plenty loud, but it couldn't handle the signal when I turned on my Vox wah pedal. The pitch was just too high, but I think it's incompatibility had more to do with it being smaller than the Fender. So, I went back to guitar center last night and exchanged it for a 100 watt keyboard amp. It definitely handles the signal better and the wah pedal is fine through it as well. I think that if you have a big guitar amp, it'll probably play fine through it, but if you are looking for a smaller amp, keyboard amps are probably better suited.

yea, i use a PA when i play my theremin out, to handle all the lows and whatnot. i've played it through my guitar setup (crate head, beringer 4x10 cabinet) and it sounds great. i do get worried about damaging it though, since the theremin does put out a much 'hotter' signal than my guitar does.

Have you applied the Etherwave guitar amp level hack from the hot-rodding manual?

Right now I'm trying to install a 50k pot to give me some flexibility in outputs - turn it to the low end for line-level output, to the high end for guitar amps. I think I'll mount the pot just good enough so I can try it now and mount it better later. I've got it sticking out of the bottom of the theremin so it's out of the way.

I'm wondering if the folks who are saying that the keyboard amp turned their theremin into a "whole new instrument" had tried reducing the line level with their old guitar amp first.

Another possibility is that the keyboard amps were much better, higher end amps. I want to try different amps at the music store to help me decide for myself but now it's looking like it will be Thursday before I can do it.

If you can get ahold of it, try to look at the frequency response chart for the amps. Some good keyboard amps actually have a woofer and a tweeter and are better at delivering consistent performance across a wider range of frequencies than a guitar amp. I think this fact alone probably makes the keyboard the most versatile choice.

I've seen a few guitar effects pedals recently that include a tube pre-amp stage. This might help "warm up" the sound before it's pumped into the amp. I haven't seen a keyboard amp with a tube yet, but I'm sure they're out there :)

It looks like the 50k pot is going to work. I was able to get a greater loudness range out of my Fender and I noticed that I have more control on the volume antenna.

Someone loaned me a digital effects pedal, so I'm going to pick up another cord today so I can try it. I may still go to the music store to try out other amps, but I like the Fender - also that it has controls on the speaker side. That makes more sense for a theremin.

Cool. You HAVE to take your theremin to the music store :) Let us know what kind of reactions you get. I went to Guitar Center last week to look at loop pedals (Billy, Steve, and Steve got me inspired), and the sales guys kept calling it a "Thurman" (as in Uma) no matter how many times I corrected them.