The SN-600 vs. SN-6 confused the heck outta me. Let me talk through it.
I eventually found a 1980’s catalog listing the SN-600 and SN-800 (the 600 is on the left). It’s a big enough pic to see that the keyed range on both the 600 and 800 are to altissimo E and neither have an altissimo F# key. I even counted tone holes for the upper stack. There are four above the B key and no front altissimo F. If you compare that to the 6 on the SN-9930, which has a keyed range to altissimo G, you can only conclude that the horn pictured in the catalog as an SN-600 has a range to altissimo E.
That’s not the end of it, though.
The really, really easy way to tell if you have an A-5 or T-5 pro model, rather than an A-4 or a T-4 “intermediate” model, is to see if you have an altissimo F#. Altissimo F# = 5 Series. So, one might conclude that the 6 Series, a professional line, all have altissimo F# keys. They don’t. The B-6 baritone doesn’t. “Well,” you could say, “Baritones generally don’t have altissimo F#. Bari players don’t use that key much and the bari isn’t very common, anyway. Most manufacturers use their older-style horns until they get lotsa orders for a new model bari.” That’s a good point, but the B-6 is Yani’s first bari. I could also argue that the market for sopraninos is even smaller than the market for baris. That’s easily seen by just looking at my stash of Yani bari and sopranino pics. I have probably 5 to 10 times more baris than sopraninos.
So, let’s look at some documentation.
The Barnes & Mullins article says that the first sopranino was introduced in June 1972 as model “SN-6,” with a keyed range to altissimo E. The Conn-Selmer website goes a step further and says that the first SN-6 sopranino was sold to Sonny Rollins in 1972, but doesn’t comment on the keyed range. Yanagisawa’s website and others say it’s 1968 with model SN-600, with keyed range to altissimo E. Riojasax says that the SN-600, with keyed range to altissimo E, was released in December 1968 and the SN-6 was released in June 1972.
So, my current opinion, based on agreement from most of my source material, is that the SN-600 is a sopranino with a keyed range to altissimo E. The SN-6, if I can ever find one, probably has a keyed range to altissimo F# or it has some small change to a bit of keywork, like the A-600.
The A-600 and (theoretical) T-600 are a bit easier to document. It’s easy enough to let Yanagisawa do the talking:
This actually tells us another thing that’s interesting: there actually were some Yanagisawa serial numbers in the form of xx80xxxx, where 1980 is the year of manufacture.