Added Info ELECTRONICS NOW Aug 1994 (v.65#8) pg. 12
Audio system integration. A knowledge of impedance matching and an understanding of spec sheets will help you integrate a high-quality public address system.
ELECTRONICS NOW Aug 1996 (v.67#8) pg. 27
A solid-state microphone transformer. Construction of a two-stage, direct-coupled, operational amplifier to match low impedance amplifier inputs. This battery-powered unit is almost noiseless.
ELECTRONICS WORLD Mar 1967 (v.77#3) pg. 68
Circuit designed to match a low-impedance microphone to a tube-type public address amplifier requiring a high-impedance input.
ELEMENTARY ELECTRONICS May-Jun 1977 (v.17#3) pg. 52
Basic building-block circuits are made from the same low-cost IC, the LM324 quad op-amp. (1) AC voltage-follower. (2) Inverting amplifier. (3) Buffer amplifier. (4) Squarewave generator. (5) Instrumentation amplifier (formed by combining the above four circuits).
HANDS-ON ELECTRONICS Feb 1988 (v.5#2) pg. 76
Build an adapter box to interface a sound motion picture projector (or a radio, stereo, phonograph, etc.) to a public address system. Est. cost: $20.
PHOTOMETHODS Jul 1985 (v.28#7) pg. 6
Impedance-matching preamp that will allow you to use an old crystal microphone with a transmitter, PA system, or tape recorder.
POPULAR ELECTRONICS [2] Aug 1990 (v.7#8) pg. 81
High-input-impedance to low-output-impedance converter circuit.
POPULAR ELECTRONICS [2] Sep 1995 (v.12#9) pg. 75
Simple single-transistor circuits. (1) Voltage regulator outputs 6-volts DC. (2) Constant-current output. (3) Simple audio amplifier. (4) Impedance-matching circuit. (5) LED-control circuits turn either off or on in the presence of a DC voltages from 5- to 9-volts. (6) Relay-driver circuit has a latching feature that keeps the relay on once energized.
POPULAR ELECTRONICS [2] Dec 1995 (v.12#12) pg. 77
Preamp circuit provides a transformerless match for low impedance microphones and can drive most system amplifiers.
POPULAR ELECTRONICS [2] Jul 1997 (v.14#7) pg. 67
Computer-designed audio networks. BASIC program eliminates the hard work in designing impedance-matching networks and attenuators for audio systems.
RADIO-ELECTRONICS Nov 1984 (v.55#11) pg. 11 (ComputerDigest)
Correction RADIO-ELECTRONICS Jan 1985 (v.56#1) pg. 5 (ComputerDigest)
"Transi-Match", a one-transistor circuit whose sole function is to match a very high impedance to a very low impedance. Est. cost: $4.
RADIO-TV EXPERIMENTER #780 Apr-May 1966 (v.20#2) pg. 73