Amp for electric violin / cello.

[DoomPixie]

Hi,
I am starting a new project for my o/h and aim to build a small valve amp for her. She wants initially to be able to play her electric violin through it and she has plans of getting an electric cello at some point in the next couple months so it would be good if it would also be suitable for this.

What she wants.

1/ small size and it does not need to be overly powerfull.
2/ clean sound, able to get "valve overdrive" and "distortion pedal type" sounds.


I would like to do this as cheaply as possible so my aim is to use as many parts that i have lying around as is possible, with this in mind i had a rummage in my "man room" and came accross amongst other things, an old Ampro stylist projector amp that i plan to cannibalise for the OPT and valves (or atleast some of them).

Parts at my disposal that may be suitable candidates for use in this amp are as follows.
PP OPT designed for 50C5.
3x 50C5,
2x ECC83,
1x ECC84,
3x ECC88,
2x XCC82,
various other valves.

One thing i have learnt is that electric violin wants more of a PA style amp rather than a guitar style but apart from that im pretty lost here.

I was initially thinking for tube lineup maybe 8D5 - ECC83 - ECC83 - PP 50C5 with maybe some switchable diode clipping useing either a 6AL5 or 6D2 (in the intrest of keeping the nasty solid state stuff away), EZ81 rectifier.

What do you think? Am i completly barking up the wrong tree. Any ideas are more than welcome, i have to start trying to work this thing out and for some reason i am having a complete brain freeze at the moment.

Cheers,
Owen

 

[tinitus]

I suppose we are talking piezo special pickup ?

anyway
lately I have noticed several new commercial amps designed especially for acoustic instruments
and also some preamps

might be worth a look, just for 'inspiration'

 

[DoomPixie]

I believe that both instruments are using a piezo style pickup mounted underneath the bridge. My research leads me to believe 100mv p-p output is to be expected but i am not allowed to do any measurements on the actual instrument so that will have to wait for her to be out one evening

EDIT: saying that it has just occured to me that this is most probably wrong as her violin atleast has a built in pre-amp that is capable of driving headphones directly.

 

[tinitus]

what kind of sound ?
jazz violin ?
or loud synth rock style ?

 

[DoomPixie]

From what she listens to and what she has been telling me i believe she is looking for the latter but with the ability to produce clean / almost acoustic sound aswell.

 

[tinitus]

.... i believe she is looking for the latter...

for the loud rock style, my guess is its a DI signal to the band PA

but I think you need to sort out the mic/pickup type first, and specs

piezos may need up to 4M ohm input

.... with the ability to produce clean / almost acoustic sound aswell.

may need adding ordinary acoustic mic...and a very different preamp input
could be more of a folk style thing

 

[Rodeodave]

Maybe a combo of high impedance JFET input, valve VAS with various limiters and EQ, and chipamp output? Nice and compact, and mono.

 

[DoomPixie]

Ok,
I have done a bit more poking.
It has a built in pre-amp with volume and EQ. Most people seem to play these through either a Bass guitar, guitar or keyboard amps. I reacon a guitar amp would be most suite to her as then she can also use it with her guitar if she feels the urge to ever get it out again.

 

[DoomPixie]

Maybe a combo of high impedance JFET input, valve VAS with various limiters and EQ, and chipamp output? Nice and compact, and mono.

To be honest that sounds an awfull lot like the guitar amp i built her, except i skipped the JFET input in favour of valves. I would prefer to go all valve on this one though.

 

[JMFahey]

I think you are shooting yourself in the foot by both trying to make a tube amp and use puny 50C5 .
You will only achieve

"valve overdrive" and "distortion pedal type" sounds.

, that's for sure ... very weak, tinny and dirty sounds by the way, only suitable to play in a bedroom (a not very large one).

I'd build an acoustic guitar type amp and add whatever processing is needed at the FX loop, and in a more controlled way.
Or even add the effects digitally during postprocessing the track.
But a tiny dirty 50's AcDc radio output stage?
Ugh !!!!
For a *cello*?
Double ugh !!

 

[DoomPixie]

im not completely set in stone on the 50C5's, i have other choices just thought it would be nice to experiment with them. This will only be a small practice amp though, it will be a combo with an 8" speaker.
As for size of the room, I currently use SET EL84 amp in my hifi and it is more than loud enough. A friend brought round one of those little marshall 1W amps with the 12AU7 PP output stage for her to try out and even that was uncomfortably loud with the violin running through it.

 

[Kastor L]

Any simple DIY violin amplifier around you can make with op-amp's?

 

[Nigel Goodwin]

Any simple DIY violin amplifier around you can make with op-amp's?

You can only make preamps with opamps, although you can use them in the front end of some power amps (but it seems fairly pointless to do so).

 

[Kastor L]

You can only make pre-amp's with op-amp's ///

Y?

 

[mcgruff]

How much clean headroom do you want, and how loud do you want to be when you hit overdrive? A 5F1 Champ - or 5F2A with tone control - might be all you need. Choose an efficient speaker if you're more interested in clean volume.

 

[caseycampell77]

for the same amount of money you'd spend building one, you can purchase this one:

http://www.carvinguitars.com/products/AG100D

check out the specs. pretty impressive.

very flexible and can be used in a variety of situations. comes in different colors as well if that matters.