Kalamazoo Amp Field Guide: Model 2

(Bill Of Materials, a.k.a. Parts List)

Technical Overview ] [ Schematic ] [ Bill Of Materials ] [ Photos ] [ Modifications ]

Kalamazoo Model 2
Revision: 3
Kalamazoo Amp Field Guide
28 Feb 2004
Bill of Materials
Qty Item Description
2 C1, C3 .01uF/400V foil coupling caps
1 C2 .0047/400V Orange Drop tone cap
1 C4 10uF/10uF/20uF/350V min. (450V recommended) electrolytic power supply cap (2)
1 C5 10/25 electrolytic tremolo oscillator cathode resistor bypass cap
1 C6 .033/200V Orange Drop tremolo oscillator grid circuit cap
2 C7, C8 .02/200V Orange Drop tremolo oscillator grid circuit caps
1 C9 .022/600V Black Cat[tm] foil or equivalent(10)
1 C10 15pF - 75pF parasitic oscillation suppressor cap, may be mylar or ceramic, from plate either to ground or to B+ rail
2 R1, R2 47K 1/2W input resistors(1)
2 R3, R13 4.7K 1/2W cathoide resistors(1)
2 R4, R7 100K 1/2W gain stage plate resistors(1)
2 R5, R6 1M Audio taper volume and tone pot
1 R8 330K 1/2W power tube grid resistor(1)
1 R9 150 2W power tube cathode resistor(1)
1 R10 100K 1/2W power supply dropping resistor(1)
1 R11 150K 1/2W tremolo oscillator plate resistor(1)
1 R12 2.2K 2W or 3.3K 1/2W power supply dropping resistor (1) (9)
1 R14 68K 1/2W tremolo oscillator grid circuit resistor(1)
1 R15 510K 1/2W tremolo oscillator grid circuit resistor (1)
1 R16 1.5M 1/2W tremolo oscillator grid circuit resistor (1)
1 R17 500K Reverse Audio taper tremolo frequency pot
2 V1, V4 12AX7A high-mu, dual triode (3)
1 V2 6BQ5 Power amp pentode (4)
1 V3 6X4 Full wave rectifier (5)
1 T1 Power transformer, 250-0-250V@60mA, 6.3V@2.5A min. (6)
1 T2 Output transformer, 5 watt min., Primary impedance: between 4K and 5K, Secondary impedance: 8
3 @1, @2, @4 9 pin miniature tube socket
1 @3 7 pin miniature tube socket
1 J1 1/4" mono phone plug with switch
1 J2 1/4" mono phone plug
1 S1, S1 Switch, SPST, 125V 1A (7)
1 DS1 117V neon pilot lamp assembly
1 FH1 Fuse holder
1 F1 Fuse, 250V 1A, 1/4" x 1 1/4"
2 TS1, TS2 Terminal strip, 2 lug no ground, or 3 lug, center ground (ground unused)
1 TS3 Terminal strip, 7 lug 2 grounds
1 SRT1 solder ring terminal for C9 ground (in rewire, for power cord ground)
1 SW1 star washer for C9 ground (in rewire, for power cord ground)
1 P1 Power cord with strain relief (8)
  1. All fixed resistors are carbon composition, but in building your own or replacing them, feel free to use your preference
  2. May be replaced with separate electrolytics, or even non-electrolytics if you have the money to spare, although it will get really, really crowded in there. Larger values may be used, but do not exceed 40uF or son for the first cap after the rectifier (RCA says 20uF max for the first cap; go beyond this at your own risk) somewhat larger values acceptable (such as 20/30/40)
  3. Lower gain tubes not recommended
  4. or EL84
  5. or 6063 or 6X6GT
  6. specs derived from observed voltages, tube manual. The filament winding should probably be capable of 2.5A .
  7. originals were piggybacked to tone and tremolo controls, power switch should really be away from all signal wiring
  8. original was 2 conductor, 3 conductor recommended
  9. Early schematics say 1K, but a 2.2K is common in the circuit. Later schematics show a 3.3K, and that's what's in the later amps. The smaller values (1K, 2.2K) are usually burnt to the point it's impossible to read the color code. I strongly recommend replacing the burnt resistor with a 2.2K/2W or a 3.3K/1W.
  10. not needed with 3 wire power cord
Miscellaneous hardware

  • power transformer bolts and nuts
  • rivets - the output transformer, terminal strips and power supply cap strap were attached with pop rivets
  • knobs
  • speaker cable connectors - later models had 3/16" female, push-on connectors, earlier models had wire soldered to speakers

Technical Overview ] [ Schematic ] [ Bill Of Materials ] [ Photos ] [ Modifications ]

Last updated: 01 September 2005

Copyright 1999 Miles O'Neal, Austin, TX. All rights reserved.

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