theremin amps!

I started with a Marshall MG10cd practice amp; well I am a Brit (and no, it doesn't go to eleven like it did on Spinal Tap). Worked OK and have overdrive plus headphone socket for quiet practice but wanted the reverb etc. Used it with a second hand ZoomG1XNext effects box. Not bad................but still wanted better sound quality.

Then decided to get a pre-owned (OK, second hand) Behringer Ultracoustic ACX450 as it had two inputs, good power (in fact with the Moog I had to fit a mixer in-line to allow any movement past one on the volume knob as it would be VERY loud) and built-in effects. Read the reports/reviews which were very good, and being a sort of keyboard orientated amp it gives great sounds. Works really well with my blues harp playin' too (Chris "Murky Stream" Clark)!!!!!!

This may sound a bit strange but... I just got my first theremin today. I set it up on my music workbench. Rather than run it through my fender amp, I ran it through one of the spare channels on my Native instruments s4 dj controller/soundcard. The best bit about this was I could still use all of the effects on my traktor dj pro software, plus my decks are plugged in to a pair of 6" krk studio monitors. My setup sounds beautiful. Warm, full bodied with a countless range of effects. I just need to rack up some serious amounts of practice time!

Roland KC-60

I've had my etherwave theremin for about 9 months.
I wanted to spend about $300 on an amp and was looking for portabilty and about 30 watts.

After auditioning a number of bass and keyboard amps I decided to purchase a
Roland KC-60 keyboard amp.
40 watts, 10" speaker, plenty loud, easy to carry, and only $250 for a floor model.
It produces the sound that I've heard in my mind's ear when I play my etherwave.

The three band EQ and the etherwave's waveform and brightness controls allows me a wide variety of sounds.
This is the amp for me.


I auditioned (in Guitar Center and 2 other music stores) a variety of bass and keyboard amps
(Behringer, Orange, Peavey, Fender, and some others I can't remember).

The theremin always drew a crowd when I plugged it in to test these amps.
That was fun, letting folks try their first theremin.
After all of that, I decided on the Roland.

UNTIL THE ROLAND I HAVE USED:
2 guitar amps
- Crate GFX-15 (15 watts, 8" speaker)
- MusicMan 112 RD (60 watts, 12" speaker)
both of these sound kind of thin without an even response over the theremin's range.

1 bass amp
- Peavey MINX 110 - (35 watts, 10" speaker)
not bad at all - even response but without the thickness and body I wanted.
This would be the one I would use if I had not bought the Roland.

1 keyboard amp
- Peavey KB 100 (75 watts, 12" speaker
Pretty nice but WAY too big and cumbersome.

At the moment I'm using a relatively inexpensive Fender Champion 600 (reissue) 5W tube amp with my Etherwave for home/practice use. It lacks some in the low end of the frequency spectrum and it hums a bit but it has a nice mid range tube sound that to (my ears) gives the Etherwave a more classic sound. It's not a linear sounding amp but I think it adds a nice color to the sound. I'm going to mod the amp and hopefully clean up the hum so it will be possible to use it in recording situations also.

What type of amplifier did Clara Rockmore use with her large diamond speaker........  Was it a stand alone tube unit or was it built right into the speaker's base?     

Clara Rockmore's amp was integrated in her theremin.

On the power supply chassis, there is a push-pull amplifier with two #59 pentodes in triode configuration each (g2 and g3 connected to the plate). The speaker output connector is connected to the secondary, most probably low impedance, winding of the output transformer which would have allowed the use of a purely passive speaker chassis with a permanent magnet.

Thanks Thierry that's more detail than I expected anyone to know since I have only seen pictures of these speakers behind the artist.     

I am using a Jensen Special design C10R 8ohm 10" in my diamond speaker powered with an inexpensive Radio Shack PA amplifier. The sound is pretty good for the small room I play in but I can't help but a tube amp to drive the speaker would produce a warmer sound. 

I'm sure that a tube amplifier will sound better with the Jensen chassis. There are lots of schematics on the Internet which use a pair of EL34 tubes in an AB push-pull configuration (or their American equivalents) and readily available input, output, and power supply transformers from Hammond. I would insist on the use of tube rectifiers in the power supply section, too. These increase the inner resistance of the power supply and they have a less sharp cut-off than semiconductor diode rectifiers, both factors will greatly contribute to a good and warm sound. Next time I stumble across such a schematic, I'll post a link here. If you find some, don't hesitate to post them here, too, for a critical review. 

Is there any risk of damaging an amp designed for acoustic instruments (such as a Fishman Loudbox) by plugging in a theremin? 

"I can recommend (since I own one for a long time) the Behringer K450-FX. It's a 40W amp with a 10" speaker and some digital effects (Reverb etc.) built in. It is not expensive (about €150 here) and the most important: It's THE amplifier on which I did the whole bass module developing and testing. And yes, with this amp and the ESPE01 module, you may remove the plaster from the ceiling... :-)"

You still using the Behringer K450-FX? I noticed it's a PA/Keyboard amp and is top rated... Just wondering if you still like it. 

I've been offered a Crate FXT30 Guitar Amp w/ DSP for $30.00... It's older but never been used more than a few times. However, it's a guitar amp and thinking a PA/Keyboard amp like the K450-FX is the better way to go... For $30 I might grab it for the time being... However, figure my sons are 8 and 10 so they will probably want a rock band eventually anyhow... ha ha. 

I have a Steinbert UR22mkII and M-Audio BX5a's on my iMac... So, I do have some decent monitors but when jamming it's not ideal... I'd rather have something to jam with. Plus I will be getting an Etherwave (or holding out for that secret project) by yearend and would like something that is good for both the theremini and an etherwave.