![[photo]](Images/Antonio/fullfront.jpeg)
Kalamazoo Amp Field Guide: Reverb 12
Technical Overview
For more information on the Kalamazoo line, see the Kalamazoo web pages at http://www.rru.com/~meo/Guitar/Amps/Kalamazoo/ .
NOTE: I have two of these now. They are very different than the Model One or Two amps. The two variants have very different acting tone stacks; both versions are picky about power tubes in terms of tone. The tone circuit in what I call the "A" variant is very annoying; one control acts almost like a volume control, and much of the knob range isn't very useful. Overall this is a clean amp, like a Princeton Reverb , or a Deluxe Reverb without much distortion. The reverb is OK, but not great. The tremolo works well. The power section is biased Class A.
Someone who asked to remain anonymous wrote in response to the above,
"For what its worth, I hate the tone controls on my Version 2 amp. The treble control is OK, but the bass control is more of a bass on/off switch combined with a volume control. The Version 1 and 1A amp use a modified James/Baxandall stack; I've never seen either Reverb 12 tone stack used anywhere else.
I have a 1965 Gibson Explorer (Ga15-rvt) which uses the 'version 2' tone stack. (doesn't match the published Ga15-rvt schematic). I share your distaste for it, and converted it to your 'version 1'... big improvement. I actually didn't mind the bass control so much, the tapped pot gave it an interesting mid-notch somewhere in the middle. What I couldn't get along with was the treble--- piercing yet lacking sparkle."
Another reader switched to the Marshall 18W tone stack, and was much happier.
Vital Statistics
Model: Reverb 12
Year manufactured:
circa 1966
Controls:
FRONT:
- Two inputs (one channel)
- Loudness (volume)
- Treble (with on/off switch)
- Bass
- Frequency (tremolo)
- Depth (tremolo)
- Reverb (depth)
- 300W AC receptacle (two prong)
- External speaker - 8 ohm (1/4" phone jack)
- Phono/tape input (mono, RCA phono jack)
Tubes:
- 12AX7/ECC83/7025 (dual triode) preamp stage 1 and tremolo oscillator
- 12AX7/ECC83/7025 (dual triode) preamp stage 2 and phase inverter
- 12AX7/ECC83/7025 (dual triode) reverb driver
- Two 6BQ5/EL84 output tubes (push-pull)
- solid state diodes for rectifier
Output Transformer:
- Unknown (proprietary numbering scheme)
Speaker:
- one CTS 10", 8 ohms with "extra heavy" 10 oz magnet
Physical detail:
- 1/2" plywood cabinet with metal corners, small rubber feet, standard vinyl handle, standard Kalamazoo tolex
- medium gauge, one piece chassis with graphics silk screened on face
- point to point construction
Miscellaneous:
- schematic and tube layout chart pasted inside amp on lower back panel
Last updated: 21 October 2007
Copyright 2000, 2006 Miles O'Neal, Austin, TX. All rights reserved. Amp photo courtesy of Antonio Salvatore . Miles O'Neal <roadkills.r.us@XYZZY.gmail.com> [remove the "XYZZY." to make things work!] c/o RNN / 1705 Oak Forest Dr / Round Rock, TX / 78681-1514