I recently bought a cittern. Actually I bought a modern cittern, which is also called an Octave mandolin or Irish bouzouki. It's not a Renaissance cittern, I have only ever seen one of these many years ago by an instrument maker at the Port fairy folk festival. I am still kicking myself that I did not spend Cathy's money to buy it.
I bought it for two reasons. I wanted something louder than my old round-backed mandolin to play dance music on (and being an octave lower it is also more useful for chordal accompaniment) and also citterns are cool.
There are four differences between my modern cittern and the Renaissance cittern that I really want:
Machine heads: The renaissance cittern's head looks like a violin, while the cittern head looks like a modern guitar and has machine heads. Having to deal with traditional pegs on my lute I am actually quite happy with this compromise.
Volume control: While the iconographic evidence is not difinitive, I am still pretty certain that citterns did not have volume and tone controls for when they were plugged into an amp. This was almost a deal breaker for me, but fortunately the panel is pretty discrete.
Soundhole: My cittern has a round soundhole, Renaissance citterns have a carved one.
Tuning: As mentioned above I have my cittern tuned like a mandolin, which is great for melodies. Renaissance citterns have a weird re-entrant tuning, so that the highest and lowest strings are only a sixth apart. Good for chords, not so good for melodies.
So there are four inauthentic things here. The first three are visual and the fourth effects operation. Of the visual elements only the volume control is an issue for the lay observer (and maybe the small Fender logo on the head), and this is effectively hidden when I play anyway. The carved soundhole would be a lovely touch if it were there though.
The question then becomes how much of an issue are the differences to an observer familiar with Renaissance instruments. I must remember to ask the northern laurels if they can tell what's wrong with it. Visually my cittern is probably on a parr with those lute guitars (guitars with lute bodies). Wrong, but different enough not to be jarringly modern.
The tuning is probably a bigger issue for me. For a start I can't play straight out of the copy of "The Cittharn School" at the Monash Library. Also if I play any of the Thomas Morley consort music I will have to fudge the music (same chords, different triads). What's more, by using the cittern as a melody instrument I am using it in an inauthentic manner.
This is an analogue of the "Is it better to drink cola from an authentic goblet or drink metheglin you brewed yourself from a plastic cup?" conundrum. The process is more important to me than the outward trappings. At least when it comes to music. So some time in the future I will be considering restringing my cittern and giving it the Renaissance cittern tuning. The problem is that it then loses its function as a melody instrument.
So I guess that what I'm saying is that I hate compromises, and somebody should buy me something from here: http://www.diabolus.org/workshop/workshop.htm with a particular eye to the gittern.