Theremin amplification

Recently I've been doing some research on amplification of the theremin, voice and other instruments, acoustic and electric, and what would be gig-worthy amplification. At home I'm mostly using a Fender Pawn Shop Special Greta, a small tube guitar amplifier, into a Vintage '50s radio extention loudspeaker cabinet that is very efficient. stock the amplifier distorts really quick, but I put a lower amplification pre-amp triode tube in it to give it more clean headroom on the volume dial and that works very well.

The common recommendation is a keyboard amplifier, an amplified monitor/PA speaker, or small portable PA sytem, or plugging straight into the inhouse PA. I noticed that keyboard amplifiers tend to get fairly heavy for the ones that put out some more watts than a practice/livingroom model. The acoustic amplifiers tend to be remarkably small and can get pretty loud.

For the rare gig and for jam sessions I've been using a VOX Pathfinder 15R solid state guitar amplifier so far, which works quite ok, but mine has an somewhat unreliable input jack, and especially when playing in the low bass range it sometimes suddenly cuts out or briefly interrupts.  

In front of the amplifier I'm using a VOX Valvetronix ToneLab for some effects and for shaping the sound, it has (guitar) amplifier modelling including a tube equalizer model and several clean/high-headroom amp models and emulation of a range of loudspeakers and a range of useful effects. So after seeing and hearing another multi-instumentalist/singer use what's called an acoustic amplifier, which is primarily aimed at singer/songwriters, using it with acoustic guitar and vocals, with voice, violin and kalimba I got the idea that such an amplifier could also work well for theremin, voice, didgeridoo, guitar and bass guitar and percussion instruments as amplification and sound reinforcement as they are suited as personal monitor/stage-mix amplifier, as a small PA in small settings and they allow to send a DI and/or line-out signal to an available mixer and PA.

Trying out some of the lower priced models in a local music store, around 300-400 Euro (Fishman Loudbox Mini and Artist, Fender Acoustasonic Junior and a Marshal Acoustic Amplifier) only the Marshal could handle the theremin's frequency range well without on one resonance point starting to rattle/buzz/distort, but the model in the shop had quite some hum and didn't really get very loud and it was rather heavy. Around or below 10 kg was my prefence.

Seeing that the Hughes & Kettner Era-1 amplifier is now about at half the price it was at its introduction in 2017, touting a 250 Watt output class-D amplifier through an 8" Woofer/Midrange speaker and a dome tweeter, in a sturdy birch-ply closed cabinet, made in Germany, and checking the available YT video reviews/comparisons, I had enough faith in it to order one, together with an inexpensive set of light PA-speaker stands. So far this turns out very well, at home and briefly tried it in my backyard too, and it handles the sound very well up to a significant loud audio level, and the speaker pole allows me to get it at head-height for good direct monitoring of the sound.

I hope to soon try the setup out in situations with a small audience (a birthday party the coming weekend) playing together with a handpan and percussion player and with another theremin player (Yeapsystar). We recently also played at a gathering/happening, where I still used my Pathfinder, and gave the PA a line out from my ToneLab for the theremin and Yeapsystar used a small microphone stand mounted powered speaker that included a small mixer, when the guitar practice amp she had been using so far suddenly malfunctioned while setting up, which also let her connect her Orba instrument.

At home I've paired the Era-1 amplifier with the Greta and the vintage loudpeaker cabinet into a stereo setup and at living room volumes can get them to match quite well in level and sound. Another acoustic amplifier I was having under consideration was the Udo Roesner Da Capo 75, but that one has no speaker pole mount, is more expensive, and I like the aesthetics of the birch plywood more than a 'black box'. The H&K Era-1 and the Da Capo 75 are both designed by founders/amp-designers who earlier founded and worked at AER, which seems to be the industry standard for acoustic amplifiers, and they both too slightly different approaches in their designs and the production. The Da Capo has been designed in Germany and France but is built in Indonesia, the Era-1 is all German design and built in Germany, and the reputation for equipment built in Germany is very good in terms of workmanship, durability and service. So far I'm very happy with my choice.

So when looking for an amplifier for theremin, do consider and look into those so called acoustic amps (besides AER, high quality acoustic amps are also made by Acus and Schertler, Italian and Swiss/Italian comapanies, and perhaps there are some budget models that do work ok that I didn't have the chance to try out). The USA has also some brands specialising in acoustic amplifiation, which may budget-wise be a better choice when based across the ocean, seen from Europe.

I think this is a very salient discussion. I have also been pretty disappointed with the sound that I get from "keyboard" amplifiers. Thankfully, I sometimes get the chance to try other amps, as I frequent a synth/theremin open-mike/synth circle thingy on a regular basis. The nice thing about the situation is that I get to try different gear in the same space, and then move around in the space as other people play with the same gear. 

After a few years, I have come to the conclusion that "acoustic" amplifiers work best for the timbres that *I like* in theremin. I'm not fond of the Fishman Loudbox, as it seems to have a weird dip in response just below the midrange. In the reasonably affordable range, my favorites have been the Marshall AS50-D Acoustic amp (the chorus and reverb are very usable!) and the Boss LT60W, which is ultimately what I ended up purchasing...it has great response, it's very compact, and it fills a small hall admirably. It also has some really good onboard effects, which I do not typically use...but having a decent looper built into the amp is pretty awesome. It also works really well for vocals, and while I do not sing, my significant other *does*

I have found other amps and combinations that do sound better, but they are all high-dollar solutions, and the Boss is pretty reasonable at about $400. And it works triple duty as a great amp for my acoustic instruments.

It is true that the signal from most theremins is a bit too "hot" for most guitar amps, but that only holds true for amps meant for electric guitar. Acoustic-style amplifiers are meant to work with all sorts of pickups and all sorts of instruments. Many of them have a "pad" button that attenuates the signal to line level...which is also great if you're paired with another instrument or voice through the same amp, as long as the pad button works per channel.

Also, I generally found that LOWER POWER amps in the 40 to 100 W range sound better with my theremins. If you need more volume, you can mike the amp through a house system...but 60W is plenty for venues up to about 1000 people. Although the sound tends to be a bit focused in really wide spaces, so miking the amp through the stack is a good idea anyway...and the sound guy can hear the balance way better at the back than you can on the stage!