The Picolo and the Bugle are different things.
The Piccolo is a headamp. It is designed to provide gain to a low output MC (or low output MI)cartridge to then feed into a phono stage.
The bugle is a phono stage. it does the RIAA thing, and provides gain.
If you have a MM, MI, or HOMC cartridge you need the Bugle.
If you have a LOMC or LOMI cartridge you need a headamp (or SUT) AND a phono stage (the headamp/SUT may be built into the phono stage) to play your fuzzy warbles.
Edited/added:
The coronet is (more or less) an all tube bugle. For comparasons you should czek out various speaker forums. IME the speaker forums have slightly broader knowledge of competing brands than the 2 that get mentioned on head-fi. Audio-GD dosnt make a phono stage, which leaves RSA to get all the headphone phono-stage business...
As far as a DIY comparason of the piccolo (or correctly a piccolo coupled to a bugle) VS a RSA shaddow one would need the schematics of the Shaddow. Historically Ray has not been too forthcoming with design details. You could always obtain either, and needledrop from the same tt.
Edited by nikongod - 9/3/10 at 11:50am