Categories: AltecTechnical

Novel Vacuum Tube / Diode Compressor: 1950

Download a short piece from RADIO-ELECTRONICS, 1950, on the subject of a DIY audio-compressor:

DOWNLOAD: DiodeCompressor1950

This promises to be an interesting unit.  It’s designed (like a Shure Level-Loc) for Mic-Level-In, Mic-Level-Out, but that could pretty easily be changed for balanced-line operation by omitting the first 12AT7 stage and using a modest step-up transformer (maybe 1:3 or 1:5) going into the input level pot, and then adding another output stage and output transformer.  (Since 1/2 of the 2nd AT7 is unused, I am thinking: eliminate one of the 12AT7s entirely, build this circuit minus the first stage using one 12AT7, and then add the output stage from the Altec 1566).  The unit promises to add distortion, and there is some sort of low-pass network before the 3rd grid that will also need some sort of variable components added in order to control the quality of that distortion.  My biggest question, though: will plain ‘ole IN4007 Diodes work in the circuit?  I plan to build this thing soon and all questions will be answered… always looking for new (old) sources of novel grit+crunch….

chris

View Comments

  • no, i have not,,, it's on the list though! It would be at the very least an interesting 'colour box' for the studio. c.

  • Hi Chris, Good news

    I found in web blog about signal clipper that hum radio guys wrote
    ORBAN specified diodes those used in signal clipper eqmt

    Those basically low voltage switching diodes
    But for the audio signal clipper ORBAN specified below

    Multi band clipper diode > 1N4148 or 1N914
    Safety clipper diode > 1N5711 or 1N5712

    Got another info from custom stomp pedel maker
    below is what he said

    Yes 1N4007 or 4006 can be used
    As long as if it's sound good to your ears
    If sounds bad or distort or squished too much
    You might have to change around with other

    What about Coil trans next to R1?

  • I wonder if one could use a tube with 2 diodes and a triode in this circuit to replace the first tube and the diode pair? Something like a 12AV6 (1/2 of a 12AX7 + two diodes) or something similar... Perhaps this approach could be used to eliminate the entire front end of the circuit as shown and still provide similar benefits...

Leave a Comment
Share
Published by
chris
Tags: alteccompressors
11 years ago

Recent Posts

9sides: Preservation Sound Radio March 2024

This month on Preservation Sound Radio: nine side-filling tracks from 1970 thru 1986, all from…

2 days ago

Preservation Sound Radio Feb 2024: best new (old) tracks

This month's show airs Tuesday 2.20.24 at 8:30PM -11:25PM EST on WPKN 89.5 FM in…

4 weeks ago

PSR January 2024: Contemporary Jazz 1967-1980

The first Preservation Sound Radio program of 2024 will air Tuesday January 16 at 8:30PM…

2 months ago

PSR Dec. 2023: Psychedelic Ballads and Dirges 1966-1976

As aired 8:30PM-11:30PM 12.19.23 on WPKN 89.5 FM Bridgeport. Enjoy. PSR DEC2023 sequence 1. Click…

3 months ago

WPKN FM Preservation Sound Radio 11.21.23

Tonight 11.21.23 8:30 PM EST: special advance broadcast of the P/S Winter 2024 Mixtape. Catch…

4 months ago

Preservation Sound Summer 2023 Mixtape

Here's the tracklist for the 2023 Preservation Sound Summer Mixtape, to be broadcast 8:30PM EST…

7 months ago