@stringy -

Do you want the Compressor pedal to play Violin live with others?  ...for recording?  Or, did you need it to play your other instruments? 

I didn't feel I needed one for playing with the pre-amp on my my violins & I do have some compression available in amp patches - figured I might only need it in multi-track recording & would deal with that in DAW. 

I have read that most multi-effects pedals have compression - OR, since you also like to sing, maybe consider something like the TC-Helicon VoiceLive Play Acoustic Guitar and Vocal Effects Processor Pedal.  Reverb, Delay, Chorus, EQ, and compression... there's more & LOOPING, plus vocal effects, too.  MUCH more effects & features - for probably about the same price as a compressor pedal & looper!  

You'll have two voices of harmony and two voices of doubling always in perfect tune using the RoomSense microphones or auto chord detection from the guitar input.

I 1st got the 'Ditto+ Looper', but then had a chance to buy a demo 'Boss RC-5 Loop Station Compact Phrase Recorder Pedal', at a reduced price (wish I would've got it 1st) - does WAY more than the Ditto+.   ...haven't been feeling well for a while now, so haven't played around with it yet. 

@stringy -

Do you have ANY controls on your electric violin? 

I already have tone & volume controls on mine - so I really don't need anything else. 

Consider visiting a music store & have some pedals demo'd for you?   

...sent you a PM with more info.