Well crap !! The only reason I bought a TFM-55 (to have rebuilt) was that I thought it had the "TFM sound"! Do I need a 45 to have the "tubey flavor" ?? Anyone want a 55 for repair?
The 55 is well thought of, and quite powerful; that it doesn't have the TFM circuit doesn't seem to have tarnished its rep. at all.
The 45 and all models that are equivalent were matched to Bob's Silver seven tube amp. The remainder of the TFM series, well, as you've seen some have a TFM circuit and some don't. The literature says they were designed to have ""information from null tests was used to create a unique sonic signature with tube-like, rich rolling bass, and soft yet detailed treble "
Then again, the owner manual states it's matched to the silver-7
If you got the TFM-55 for a decent price, you'd probably enjoy it very much.