Dynaco PAM-1 Preamplifier

eBay Item #286990753; 2 PAM-1 units with DSC-1 Stereo volume control


A single 12AX7 tube acting as a feedback pair with equalization determined by feedback at frequency extremes acts as a low level amplifier for magnetic cartridges, microphone or tape head. This section has a voltage gain of 50 to bring up low level sources to a point comparable to inputs from high level sources such as radio tuners, tape recorders, etc. A second 12AX7, acting as a similar feedback pair, is the tone control section; and tone control action is adjusted by control of feedback at frequency extremes. This section has a voltage gain of 10 bringing the various inputs up to a high enough level to energize any popular power amplifier.


Inputs: Low level magnetic cartridge, high level magnetic, radio, TV, tape, special optional low level.

Outputs: Tape, audio output.

Controls: Selector and equalization, bass, treble, volume, tape monitor, loudness and hum balance.

Tone Control Range:

±14 dB at 20,000 cps;
±20 dB at 20 cps.

Phono Equalization: RIAA, 78 rpm, original LP.

Distortion: Less than .1% intermodulation at sufficient output to drive all power amplifiers. This figure unchanged at any setting of volume control.

Response: ±.5 dB 6 cps to 60 kc if tone controls accurately zeroed. Response not affected by position of volume control.

Transient Performance: Passes square waves without deformation or ringing from 20 cps to 20 kc at any volume control setting. No overshoot or bounce on pulse type signals. Instantaneous recovery from overload.


Less than 3 microvolt equivalent noise input on RIAA.
Less than 1.5 microvolt equivalent on mike connection.
Between 70 and 74 dB below level of 10 millivolt magnetic cartridge.


54 dB at 1000 cps on RIAA input.
20 dB 20 cps to 20 kc on high level inputs.


Output impedance 1000 ohms.
Terminating impedance 500,000 ohms (provision for 250,000 ohms).

Tubes: 2 12AX7 (ECC-83), 1 selenium stack.

Power Requirements: 200 to 400 volts dc at 3 to 4 ma, 6 volts AC at .75 amps.

Accessories: PS-1 dual power supply; PM-1 panel mount kit; DSC-1 stereo control

Designed by:

Ed Laurent

Year Introduced:





Companion piece to the Mk. III, Mk. IV, and Stereo 70. Powered by DC from an octal socket on the power amplifiers, or by the optional PS-1 supply (also designed by Laurent).

This page created and maintained by Greg Dunn.
Copyright © 2000,2001 Greg Dunn