Pro Audio Equipment

There is some overlap between pro and consumer audio equipment, so check both categories.

AKG C-451 microphone information
Allison Research Kepex 500 Gate schematic
Altec 260A 260W Commercial Power Amplifier schematic
Altec A332A amplifier schematic
Altec 428B Microphone Preamplifier schematic
Altec 436C Compressor Amplifier schematic & technical letter #10
Altec 438A Compressor Amplifier manual & schematic
Altec 444B Compressor Amplifier data sheet p.1, p.2, schematic, parts list/relay hookup
Altec 459A Program Amplifier schematic
Altec P522B Power Supply schematic
Altec 633 "Saltshaker" Dynamic Microphone data sheet, specs
Altec 639 "Birdcage" Dynamic/Ribbon Microphone data sheet, specs
Altec 1564A Preamp Power Supply schematic
Altec 1566A Mixer Amplifier manual & schematic
Altec 1567A Mixer Amplifier data sheet, specs, schematic
Altec 1568A 40W Commercial Power Amplifier schematic
Altec 1569A 80W Commercial Power Amplifier schematic, data sheet, specs
Altec 1570B 170W Commercial Power Amplifier schematic
Altec 9473A Limiter Amplfiier manual & schematic
Ampex AA-620 speaker amplifier schematic, performance check info
Ampex AG-300 brochure
Ampex AG-300 schematics
Ampex AG-350 tape recorder electronics schematic p.1, p.2
Ampex AG-350 tape recorder remote control schematic
Ampex AG-440 (i.e. AG-440A) schematics
Ampex AG-440 remote control schematic
Ampex AL-500 Data logger tape recorder brochure
Ampex AM-10 mixer brochure p. 1, p.2
Ampex AM-10 mixer schematic p.1, p.2, p.3, p.4
Ampex 200 tape recorder schematics: pwr supply, playback amp, record amp, control, relays, top plate, remote cntrl
Ampex 300 tape recorder schematics: record amp, playback amp, monitor bridge, osc. coil, remote control
Ampex 350 tape recorder electronics (cat. No. 5701R3), 7.5/15ips schematic
Ampex 350 power supply (cat. No. 3741) schematic
Ampex 350/351 remote control schematic (same for AG-350)
Ampex 351 tape recorder electronics (cat. No. 30960) schematic
Ampex 375 60cps capstan generator schematic
Ampex 385 mixer schematic
Ampex MR-70 tape recorder schematics: electronics, sel-sync amp, 40dB mic pre, 60dB mic pre
Ampex MX-10/MX-35 mixer schematic
Ampex MX-10 mixer brochure
Ampex MM1200 tape recorder schematic, motor drive schematic
Ampex PR-10 tape recorder schematics: playback, record
Ampex 600 electronics schematic
Ampex 601 electronics schematic
Ampex 612 speaker amplifier schematic
Ampex 620 speaker amp schematic, performance check instructions
Ampex 2012 amplifier schematic
Ampex 3671 mixer schematic
Ampex SA-10 speaker amplifier manual p.1, p.2, p.3, p.4, schematic, tone control schematic
API 321 mic preamp schematic
API 325 line amp schematic
API 2520 op-amp data
API transformer data page 1, page 2
CBS Volumax 400 Limiting Amplifer schematic
CBS Audimax III model 400 Limiting Amplifier schematic
Collins 26U1 Peak Limiting Amplifier schematic
Collins 356E-1 Limiting Amplifier schematic
D.W. Fearn VT-2 microphone preamp manual
Gates SA-39B Limter manual w/schematic (very poor quality)
Gates "Sta Level" Limiting Amplifier schematic
GE BA-5A Limiting Amplifier schematic, power supply
Gotham Audio record lathe amplifier PFB-150-WA schematic, power supply PS-150-W schematic
EMT 140 reverb system schematics: playback amp, output amp (mono)
EMT 140 reverb system schematics: playback amp, output amp (stereo)
Fairchild 670 Limiter/Compressor schematic p.1, p.2, p.3, p.4, p.5, p.6 (not very clear)
Fairchild 670 Limiter/Compressor schematic (redrawn), front panel
IPC (Simplex) AM-1026 amplifier schematic (very blurry)
IRT Kompressor-Verstarker schematic
JBL speakers, drivers, and electronics datasheets in .pdf format (does not include early JBL)
Klangfilm Bionette 31620 theater amp schematic
Klangfilm Euronette 31601 theater amp schematic
Klangfilm Euronor 35700 theater amp schematic
Langevin 101-D power amplifier brochure w/schematic
Langevin 117-A amplifier module manual w/schematic
Lorenz LVA 75/47 theater amplifier text & schematic
Motiograph PA and MA-7505A amplifier manual & schematic
Muzak 975 amplifier schematic
Neumann U47 microphone
Neumann U48 microphone
Neumann M249 microphone
Neumann U67 microphone preamp, power supply
Neve 1081 channel amplifier module information
Orban 111B spring reverb schematic
Orban 672A equalizer schematic
Philips 2843 amplifier manual w/schematic (de/nl)
Philips 2853R amplifier schematic
Philips EL 6400 PA amplifier schematic
Philips EL 6411 PA amplifier schematic
Philips EL 6420 PA amplifier manual w/schematic
Philips EL 6425 PA amplifier manual w/schematic (nl)
Philips EL 6431 PA amplifier manual w/schematic
Pultec EQP-1A, -1R Equalizer manual w/schematic, construction project 
RCA BA-1A two-stage preamp schematic
RCA BA-3C program amp schematic
RCA BA-4C monitoring and recording amp schematic
RCA BA-6A limiting amplifier simplified schematic
RCA BA-21A preamplifier schematic
RCA BA-23A program amplifier schematic
RCA BA-24A monitor amplifier schematic
RCA BA-25A AGC program amp block diagram
RCA BA-31A preamplifier schematic
RCA MI-9377 amplifier schematic
RCA MI-12188A P.A. amplifier schematic and upgrade info
RCA OP-6 portable remote preamplifier schematic
RCA OP-7 portable mixer amplifier schematic
Schoeps M221B microphone schematic
Siemens V 004 magnetic tape head amplifier schematic
Siemens V 408a power amplifier schematic
Sennheiser MKH-105 RF Condensor Microphone schematic
Sennheiser MKH-405 RF Condensor Microphone schematic
Shure microphones and mixers - links to datasheets in .pdf format
Shure M62 audio level controller manual, schematic
Shure M62V audio level controller manual w/schematic
Shure M63 "Audio Master" manual w/schematic
Shure M67 microphone preamp/mixer manual w/schematic
Shure M68 and M68FC microphone preamp/mixer manual w/schematic
Shure M675 "Broadcast Production Master" manual w/schematic
Sony C-37A condenser microphone manual w/schematic
Spectra-Sonics 610 "Complimiter" manual w/partial schematic (1.6Mbyte file)
Stromberg-Carlson APH-1200 P.A. amplifier schematic
Stromberg-Carlson AP-55/AP-56 P.A. amplifier schematic and upgrade manual
Stromberg-Carlson AP-80 P.A. amplifier schematic and upgrade info
Stromberg-Carlson APH-1050 P.A. amplifier schematic
Studer C37 tape deck schematics
Telefunken V72a microphone preamp schematic
Telefunken V73 power amplifier schematic
Telefunken Ballempfänger E 1 (amplifier) schematic
Telefunken Ela B 1200 - Tonabnehmerverstärker schematic
Telefunken V 301/1 power amp schematic (P-P AD1 triodes)
Telefunken ELA V 530 summing amplifier schematic
Telefunken/TAB Varicom compression module schematic
Telefunken V72 line amp schematic
Telefunken V76s amplifier schematic
Teletronix LA-2A Leveling Amplifier (compressor) schematics & manual, construction project
Tubetech PE-1A equalizer (similar to Pultec equalizer) schematic and description
Universal Audio 1108 Mic Preamp schematic
Universal Audio 175 Compressor schematic
Universal Audio 176 Compressor schematic
Universal Audio 177 Compressor schematic
UREI Teletronix LA-2A Compressor schematic, schematic
UREI LA-3A compressor schematic
UREI LA-4 compressor (black-face) schematic
UREI LA-4A compressor (silver-face) schematic
UREI 1176 "Blue Line" Compressor schematic p.1, p.2, LN mod
UREI 1176LN series F Compressor schematic p.1, p.2, p.3
UREI 527 equalizer schematic
UREI 533 equalizer schematic
UREI 537 equalizer schematic
UREI 545 parametric equalizer schematic
UREI BL-40 "Modulimiter" schematic p.1, p.2, p.3
Valley 400 Mic. Processor audio schematic, control schematic
Western Electric 8-A, B, C amplifier schematics
Western Electric 9-A amplifier schematic
Western Electric 41A amplifier schematic
Western Electric 42A amplifier schematic
Western Electric 86A amplifier schematic
Western Electric 87A amplifier schematic
Western Electric 91A amplifier schematic
Western Electric 92A amplifier schematic
Western Electric 142A amplifier schematic
Western Electric 143A amplifier schematic
Western Electric 728B speaker brochure
Wetern Electric 1126 Limiting Amp schematic (hand-drawn)
Wurlitzer 680 amplifier schematic (not very clear)
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Recommended Archive Sites:

Cayocosta - Pro Audio Equipment DIY Resources
Ampex Mailing List Home Page - parts sources, schematics, good info from the Ampex (tape recorder) mail list.
Triode Electronics - lots of information
Film-Tech - on-line manuals and schematics for film projectors and related equipment
Waltzing Bear Audio - a growing collection of Pro-Audio schematics
AudioAntik - Information on tubes, tube audio electronics, old test equipment and tube friendly speakers. (from Europe)
Shure Discontinued Products - user and technical information on virtually all their discontinued products.
Purple Audio - schematics of classic compressors, mixers, mike preamps, etc. in their "resource" section.
JBL Discontinued Products - drivers, cross-overs, amplifier, etc. manuals or specs.
AudioSharing - a Japanese site with high-quality scans, mostly of Western Electric stuff, but more is coming.

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