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Equipment file · Valve compressor / AGC amplifier

Sta-Level compressor

Gates · 1956

Evidence status · documented

Identity and core specifications are documented; some historical fields remain unavailable.

The Gates Sta-Level (M5167), documented in an instruction manual dated 30 April 1956, used a 6386 variable-mu valve to give roughly 3.3:1 compression with low distortion. It became a fixture of AM radio studio chains.

Introduced
1956
Category
Valve compressor / AGC amplifier
Intended use
Automatic gain control in broadcast audio chains
Production
Gates Radio Company, Quincy, Illinois, from 1956

Equipment photographs · 1

Gates Sta-Level levelling amplifier in a rack

1 / 1 · Gates Sta-Level levelling amplifier in a rack

Gates Sta-Level levelling amplifier in a rack·eyeliam·CC BY 4.0

Why it mattered

  1. 01

    Its smooth compression became associated with the sound of 1950s–70s AM radio.

  2. 02

    Its approach to automatic level control prefigured the compressors later inserted on live vocal channels.

Engineering record

Gain and ratio
35 dB gain with pads (62 dB without); about 3.3:1 above a 10–12 dBm threshold[1]
Distortion
1% or less from 50 to 15,000 Hz over 0–30 dB of gain reduction[1]
Valves
Two 6V6, a 6386, 12AT7, 6AL5, OB2 and 5Y3GT[1]

Original pricing

No reliable period price located

2026 equivalent

Not calculated without a reliable original price.

Public price evidence was not sufficient to publish a defensible original figure.

Use in the field

No named deployment could be tied to this exact item by a checked source yet. Know of one? Suggest it on the contribute page.

Manuals & original documents

Sources

  1. 1Instructions M5167 Sta-Level AmplifierGates Radio Company · manual · 1956-04-30
  2. 2Vintage Audio: The Sta-Level Turns 60Telos Alliance · reference · 2016-03-28

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