more info

FYI
•   On HRM, clean and OD channels have separate master volumes
•   On Non-HRM, they share an master volume.
•   When you add a Dumbleator, the return line is the master volume.
Non-HRM’s come to harmonic feedback easily.  Mid-heavy.   Rich w / sustain.  Emphasis on mid harmonics.  More singing sustain.  OTS will sound a little warmer on the clean side compared to S&M.
HRM’s – more dynamic and percussive, very touch sensitive.  Less OD.  Not gritty or buzzy.  Have internal trimmers for TMB.  HRM series are 90s.  The HRM is much gainier and tighter on the OD
Overtone Special
•   Thicker and warmer than S & M
•   Less O.D.
•   Smoother and deeper sounding.
•   OTS will sound a little warmer on the clean side compared to S&M.
Overtone Special S & M
•   Much brighter OD and more aggressive.
•   A rock machine, but not as good at cleans.
Overtone Special 183
?
Overtone Special FM (#102)
•   Skyliner clean tone stack with a Non-HRM OD.
•   More “Chime y” clean tones.
•   More focused OD with a almost horn sound.
•   Very bright amp.
•   Needs a Dumbleator

Overtone HRM
•   Stands for Hot Rubber Monkey
•   Has a second tone stack just for the OD channel.
•   Marshally
•   Very refined
•   More compression
•   Smooth singing OD
•   6L6’s
•   Jazzz fusion but can get dirty
Overtone HRM Bluesmaster
•   Early raw Fender / Marshal tone on steroids.  Like a Bassman
•   Great Cleans (sing and sustain)
•   Less smooth OD and much less compresed than above.
•   OD is a bit raw and edgy.  Meaty and fat.  Lot’s of gain can be had.
•   Cleans are very girthy and has more bass.
•   Less clean headroom than all other OTS amps.
•   Needs Dumbleator.
•   Great blues / rock / jazz
•   More cord friendly and string definition.
•   Bluesmaster version has a smoother overdrive, but cannot be as
aggressive as the regular HRM.
•   excellent cleans, but the OD isnt gainy but more articulate.
Overtone HRM MK II
•   A bit more hair on both channels than the FM 50.
•   OD is crunchier and more compressed than FM.
•   EL34’s
Non HRM Classic EQ
•   excellent cleans, but the OD isnt gainy but more articulate.Great sustain
•   Singing OD
•   Very touch sensitive and not much compression.
Non-HRM Skyliner EQ (Regular Overtone)
•   Little less Fendery.
•   EQ is a little more Dumbley
•   Better cleans than above.Great sustain.
•   Better string to string definition.
•   The Presence is focused around the high freq. only.
-HRM Skyliner Non EQ
•   Same as above, but gain stage is not classic Fender.
•   More headroom, definition and punch.
•   More alive cleans and smoother OD.
•   Small bit of compression.
•   Touch sensitiveOn HRM, clean and OD channels have separate master volumes
•   On Non-HRM, they share an master volume.
•   When you add a Dumbleator, the return line is the master volume.
Non-HRM’s come to harmonic feedback easily.  Mid-heavy.   Rich w / sustain.  Emphasis on mid harmonics.  More singing sustain.  OTS will sound a little warmer on the clean side compared to S&M.
HRM’s – more dynamic and percussive, very touch sensitive.  Less OD.  Not gritty or buzzy.  Have internal trimmers for TMB.  HRM series are 90s.  The HRM is much gainier and tighter on the OD