I've posted these CMI amps before - they are really sort of "over the top" in design which gives them a rather mad scientist / Industrial design look. Some of these use the 8417 output tubes which are sort of Industrial KT88's - I am told they take very high plate voltages and can run hot for long periods. This one is actually one of the smaller versions of this amp - it only weighs 80lbs (?!) - they have another version that has 3 spekaers that clocks in over 130 lbs!!
The Phaser effetct was built into these amps and the Maestro pedal would control it.
Vintage 70's Guitar Amp - $200 (Menifee)
--------------------------------------------------------------------------------
Date: 2009-10-21, 1:02PM PDT
Reply to: sale-xw4g3-1431672204@craigslist.org [Errors when replying to ads?]
--------------------------------------------------------------------------------
Gibson made in the 70's. In good condition, rolls, its heavy about 80 pounds. Has original Maestro footswitch phaser pedal. 100 watts, two original 12" speakers.Asking $200 obo Email or text if interested. tineil88@yahoo.com 951. 746. 9514
Location: Menifee
SG Systems amps had a hybrid tube power section and solid-state preamp with two extremely rare RCA 8417 power tubes and an RCA 12AX7A (the latter is possibly a phase inverter, driving the two power tubes, similar to the early MusicMan amps, which had a 12AX7 phase inverter between the solid-state preamp and the power sections). Designed by Bob Crooks of Standel fame and manufactured by CMI ELectronics (Chicago Musical Instruments - former parent of Gibson - later to become Norlin Music) in Crooks' old plant in El Monte, CA. Models included a bass version as well as a PA system. Varied speaker configurations were the biggest difference between the models: 1-15, 2-12s, 4-10s, 6-10s, 2-10s & 1-15. All models had two channels, one clean and one with effects, each with two inputs (Hi and Lo impedance). Channel two includes a built-in Maestro (PS-1) Phase Shifter with 3 speeds, reverb, "wave form" (Maestro sine “fuzz”) distortion, and a “Notch Shift" feature that simulates an EQ with 4 presets. (The bass guitar versions such as the SG-215 did not have the phaser, fuzz or reverb.) All effects are controllable via an optional footswitch (PSFS-2). Both channels include separate oversized and easy-to-read volume, bass and treble controls. The effects channel adds Midrange (tone) and Accent controls, the latter being similar to an attack or presence control. A master volume knob controls the mix of both channels. The open-back cabinet is covered in lightly-grained black tolex and the edges are clad in aluminum angle stock with metal corner protectors giving the cabinets the look of an Anvil road case. The grille cloth is black with a brushed silver border and the speakers have chrome voice coils (as an option, these amps could be ordered in blue denim with blue grille cloth, and Altec speakers may have been an option). A heavy duty leather handle is installed on the top of most cabinets which roll on large round casters. (Taken from a review I posted of an SG-410 on Harmony Central.)
ReplyDeleteI've been playing a 1956 Les Paul through mine since 1980. the best.
ReplyDeleteMan, I can keep up with most new amps, - and then some. Love the tone.
My back is permanently bent and my right arm is longer from carrying it up and down, etc...
Picked up my SG 212 in '88. Loud as HELL and clean all the way to the top with a very individual, dry tone. Something to do with those horseshoe magnets maybe? I got loopy one night and did some painting over the stained up blue denim cover. It's pretty crazy looking now. I gotta find a home for this thing though, I'm playing ukulele now and don't need the extra "furniture" in my little place. Holler if you're interested and in the SF Bay area. ohgood@hotmail.com
ReplyDeletei have a 1974 SG-410 in the blue denim with all 4 original speakers, (2 of which have been replaced with celestions for a deeper tone.) Now the head does power up, but makes a humming noise, not sure what is causing it though. A few wires are disconnected from various places and the footswitch jack has been removed and the remaining wires are taped off. It came with two 6L6's and one 12ax7, which appear to be new and worked when used in another tube amp. If anyone has any schematics or info on where to find schematics, please contact me. my emails are "jtoensing@yahoo.com" and also on facebook under my name, James Toensing. (see a clear green BC Rich guitar played by cousin IT.
ReplyDeleteBad capacitors in the power supply . disconnect power inspect the amp out of the case look for buldging or leaky capacitors, usual a blown cap will spew polyvynal chloride which dries to a white power, ( don't inhale it, bad stuff like liver damage) replace the capacitor mark the positive and negative terminals , buy the parts from Parts Express on the internet. Best to look for a TV repair shop to do the work
Deletejust aquired a head/6-10 cabinet speakers all work,however amp turns on,tubes glow but no sound whatsoever
ReplyDelete