You can't add patches to the GR-33, as far as I know. However I'm sure you could tweak what you need. There is a banjo waveform in there - it's number 95 in the Tone. The best way to think about the Roland GR-33 guitar synthesizer is with ambivalence. Ludgerhesse's page - GR 33 patches and an excellent patch editor.

Roland's best-sounding, most advanced guitar synth yet! Greatly expanding the range and quality of sounds currently available to guitar players, the GR-33 employs an upgraded sound engine, new effects, amazing speed, and an enhanced user interface. Its sound source is equivalent to Roland's venerable JV-Series Synth module, capable of producing some of the richest, most interesting instrument sounds and lush effects around. Features include dedicated chorus and reverb processing, plus 25 multi-effects, massive wave memory, 350 stunning instrument sounds, an output select switch that allows use with conventional amps, onboard arpeggiator for instant creation of various arpeggios, a synth harmonist feature, assignable onboard expression pedal, and access to the world of MIDI music and computer-based sequencing. There's definitely a setup and learning curve.

I had to edit some patches to my taste and style. Pay your dues and the GR-33 will pay you back many times over. Generally, a more precise picking technique is called for, but some sloppy techniques render some nice sounds.

I love the organs and pianos. Makes me sound like a real jazz keyboard player. Soft string pads can make a lush background for guitar chords.

You can transpose individual strings for instant synth OPEN TUNINGS! The 13 pin cable can be damaged if pulled hard, so be careful, and get a spare. My GK2a pickup came factory installed in my Ibanez RG series guitar. When I first got the synth I had tracking problems. I would play a note and it would not play on the synth, or the wrong note would play. This drove me crazy.

However I was able to fix the problem in 3 ways. Now it works fine. First I changed the gage of my guitar strings.

After Effects Template - Happy Wedding on this page. I went from 009 to 010. Next I raised the GK2a pickup so it was closer to the strings. Finally I found hardness settings for string plucking for each patch. I seem to have a light touch.

These things fixed the tracking, but once in a while I will get a delay from the time I hit the string and when the note is played. This takes a little time to get use to. Over all the sounds are incredible. Even with my slight tracking problem.

I would say this is worth every dime I spent on it.