Burns B3 Pro... best amp?

Aloha Theremin World :)
I just purchased my first theremin. The B3 Pro in *walnut*
it hasn't arrived yet but I wanna pick up a practice amp NOW.
Kathy Burns said their theremins are built with guitar amps in mind. I found this one on craigslist for $40.
"Marshall MG10CD 40 Watt"
I don't know much about amps. can you please advise? I don't need anything fancy. just something clear and simple enough to be encouraging.

Thanks for your time! ~A~

whoops. The craigslist guy just told me the amp is actually 40watt output, 10watt input. is that enough watts to even get any sound out of? thanks! ~A~

omg. reverse that. it's a 10 watt amp.

Unless you need something that's ultra portable, I wouldn't recommend the Marshall MG10CD. You'll certainly never play a concert with it, and the speaker is too small (6 1/2") to provide a satisfyingly rich tone. I have used a Marshall MG100DFX, which wasn't a bad amp for a theremin (12" speaker).

Personally, I would recommend something in the 10" to 12" range. 12" is better, if you can afford it. If price is an issue, you can always find a decent used amp. 50 to 60 watts is more than most people will ever need, unless you intend to play very large venues and are competeing with other instrumentation.

I have a Roland DAC-15XD amp from the 1980's. It's only 15 watts, but believe me it's LOUD. It has four 4" speakers, so it's not great for theremin. I keep it around because it's small, light-weight and has built-in delay, flanger, and chorus!

We've recently been told the "volume" knob on the Burns B3 Pro is a "gain" control. This would allow you the option to use any guitar amp without overdriving it. Keyboard amps are always a good option.

Reverb is a very nice onboard option to have. Unfortunately, you'll find it on more guitar amps than keyboard amps. Of course, reverb (and delay, etc.) can be added with a stompbox or multi-effects pedal.

If you're not too picky about condition, you can get a decent used Roland KC-100 keyboard amp (12" speaker, 60 watts) for between $100 and $150. It's got four channels (including a mic input) plus bass and treble controls. (It's a discontinued model. They've been replaced by the KC-150.)

Only you know what kind of controls you want and the sound you want. Your best bet is to take your theremin to one or more music stores and try a variety of amps (even if you're going to buy used). That's the only way you're going to know what you want. The amp/speaker is a VERY important part of a theremins sound.

Thanks for the detailed reply Jeff. I appreciate you takin the time.
Yeah, I figured the amp was an important element to the type of sound I'm hoping for. I'm an absolute beginner to the theremin so at this point it's all question marks for me (???) All I know is I chose the B3 Pro in hopes to achieve that classic haunting "strings" sound while learning to play.... alone, in my small home. not playing any concerts any time soon. Just looking for something that won't have much distortion. just clarity. and small. an simple. Being that the basic moog theremin amp is only 15 watts I figured I might get away with a decent sound from this 10watt that gets great reviews as a guitar amp.However, after your feedback I'll give it more thought. Problem is, here on maui it's slim pickins. Our only music equipment shop is a ukulele store. And shipping here is insane.
Best to you, ~A~

A 40 watt amp with a 6 inch speaker would be quite a little monster!

That is the common mistake people make adveratizing amps on craigslist or ebay. They mistake the power the amp draws from the 120 volt plug in the wall with the output power to the speaker. A 10 watt speaker would reasonably draw about 40 watts from the wall. 10 watts turns into music, 30 watts is dissapated as heat. These things are really power inefficient. I have a 20 watt Fender Automatic amp here, on the back is stamped 90 watts.

The good thing about this type of cheap little practice amp is that; it is cheap and little, often they have headphone jacks which can be nice when you want to play quiet, often they have RCA input jacks so you can play along with a portable CD player or MP3 player. Probably the most practically good thing about this family of cheap little guitar amp is that when you buy your 13-year-old son a guitar and amp for Christmas, and he quits playing guitar after 2 months, well - ya haven't wasted much money. That is probably the realistic use of 90% of such amplifiers.

Take the "rave reviews" that you see on Harmony Central with a grain of salt. They are typicall written by 13-year-old boys who just got the item for christmas and the novelty has not worn off yet. These are exited young guys who have never actually plugged a Gibson Les Paul into a Marshall Plexi or JCM800. That is why they compare a $70 amp with a 6 inch speaker with their favorite death-metal-tones. Really, these little guys are OK practice amps for cheap, but the clean voice is usually flat and dead, and the distortion is usually similar to a coffee can full of angry bees.

A note on output power
Output power and Sound Pressure Level have a non-linear relationship. That is, a 20 watt amp isn't twice as loud as a 10 watt amp. In reality a 20 watt amp is just noticabaly louder than a 10 watt amp. And 50 watts is about the next noticable step louder, and then 100. The 15W Moog amp is probably not significantly louder than the 10 watt "Marshall". If it is, it is more likely due the the larger surface area of the 8 inch speaker. A 10 watt amp can be plenty loud for playing in a living room.

Wow, I accidentally did a double post. I guess I might as well rant and ramble some more...

Guitar amplifier power has a lot of voo-doo and misunderstanding surrounding it. A lot of people think tube-watts is louder than solid-state-watts and weird stuff like that. The method for calculating an amps power is by replacing the speaker with a power resistor of the same ohms as the impedance of the speaker, hooking a scope probe across the load, and putting a smooth sinewave into the input jack. Then the volume knob is rolled up until the scope trace of the output sine wave starts to clip at the peaks and valleys. The vollume is rolled back just until the wave is a clean sine again. The ouput power is calculated at this point from the voltage across the load at this setting. This is the maximum CLEAN volume of the amp. The volume knob could be somewhere in the middle, but this is the max clean power the amp produces before going into distortion. Many guitar amps are designed around using a lot of distortion and clip early on the volume knob setting. Rolling the volume knob up increases the distortion and the volume. But (the big but) the amp was rated at its maximum clean sine output, which may be 5 out of 10 on the volume knob. This amp may seem louder than another amp rated at the same power that doesn't clip until the volume knob is at 8 out of 10. Once you drive these suckers into distortion all rules (and common sense) are off.

Blah, blah, blah, off topic sewage, sorry...

Anyway, the most limiting part of the "Marshall" MG10CD isn't its 10 watt power level, it is its 6-inch speaker(and really, the fact that it is a toy amplifier). I agree with Jeff about the speakers. You really are not going to get a great full sound out of a speaker smaller than 10 inches. Either for theremin or guitar.

Also most of the budget amps badged Marshall are geared towards clipping distortion and EQ'ed heavy on midrange, and not clean reproduction of the input signal. This may sound good to the 13-year-old with the Squire Bullet Stratocaster, but it may not be good for theremin.

The cheaper amps labeled Fender may be more geared toward clean tones, and often include reverb.

And as Jeff suggested, Keyboard amps may be a better solution overall. They are typically voiced for a wider frequency range, and they typically are excellent at producing a nice clean output without clipping.

Overall I don't think you are going to get a suitable amp for $40. This really is the bottom of the barrel kids practic amp range.


I would like to take this opportunity to be a guitar amp grouch and point out the the use of the word "Marshall" in quotations when discribing the MG10CD was done intentionally because real Marshal amps are not filled with integrated circuits and other evil little silicone contraptions. Real Marshall amps have two big honkin' transformers, a fistfull of 12AX7 and a pair (or quad) of EL84 GLOWING BOTTLES OF JOY!

Thanks for the school'n guys! :D
Chainsaw .. I think my heads gonna explode.
Serious tho. thank you Jeff and Chainsaw. lots of valuable info there. it's sinking in s-l-o-w-l-y. I have lots to learn.
So after I told craigslist guy I wasn't gonna buy his baby amp. I was actually given a baby amp by my boyfriends dad. He had this lil yamaha 10watt cube in the garage and said "here ya go!" can't beat free with a smile I guess. But turns out my guy has a Fender 65 reissue twin reverb amp that he got back in the early 90's. It needs to be repaired though. makes an awful crackling feedback sound. Getting that repaired is probably my best bet though being that I don't have a bunch of dough. Any feedback on this particular model or any idea what that terrible sound could be?

Thanks guys! ~A~

Beware of the Moog 15W amp! It's just rebranded Chinese crap. I sold mine long time ago to someone who uses it as a backup amp now.

For the record, I have a Peavey KB-1 (keyboard amp, 15 watts, 8" speaker) and I am satisfied with how it sounds with my standard B3 (I also play in a room, no concerts or big venues).

However my budget is quite limited and so is the space I have in the room, so I have never tried bigger, better amps. Perhaps I would think that mine is crap if I tried one.

I also think reverb sounds great with theremins (and with the B3 in particular). If your amp has no built-in reverb (as is the case of mine) and you don't want to spend money on a separate effects unit, you can add reverb with a PC (I use Guitar Rig for that, but I think many programs do it).