Magnatone Guitars!

New for Fall 2013, a complete guide to Magnatone guitars and the stories behind them!

1938-1960 Steel Guitars

1956-1963 Bigsby/Barth Era

1964-1966 Starstream Era

 

Magnatone Custom M15A

Special thanks to George Nichols and Brunswick Amplifiers for providing this photograph.

Years 1965-1967 (maybe as late at 1968)
Series Custom Series
Channels two
Power 4x 7189A (two pair for stereo)
Power Bias fixed bias
Preamp 3x 7025
Reverb 12AX7
Vibrato 3x12AU7, 12DW7, 8 varistors
Phase Inverter 2x 12DW7
Speaker 2x 12" Oxford Alnico 16ohm (spring-fall 1965)
Speaker 2x 12" Jensen C12P 16ohm (fall 1965 and later)
Rectifier solid state
Output Trans10K:16ohm
Output 2x 38 watts peak
List Price $580 (1965)

The M15A is a 1965 replacement of the M15, please see that page for details of the M15 circuit. This page only addresses changes to the M15.

Reverb Changes

See the M15 and M15A reverb comparison for a complete review of reverbs used on these amps.

Preamp Change and Tone Boost

Both the M10 and the M15 received preamp design overhauls in 1965. The 1963-1965 M15's contour switch with "mellow", "normal", and "bright" settings, was immediately following the first gain stage of the preamp, and the entire preamp was 2 7025 gain stages with volume and tone in between.

The new design moves the contour switch to a RC circuit selector after the second stage and uses half of an additional 7025 to make up the gain loss in the RC circuit.

I think this preamp circuit might have first been used on the 1959 190 "treble plus".

Speaker Change

The new Custom Series lineup for 1965 does away with any amp that doesn't have a 12" or 15" speaker. The M15's two sets of 8" Oxford and 3" tweeter speakers are replaced by 12" Oxford Alnico speakers, which, sometime in the fall 1965, were replaced with Jensen C12PS ceramic speakers (M10 8"/3" pair gets treated to the same 12" replacement).

Color Change

Like all Custom Series amps left in the catalog for the 1965 re-vamp, the gold control panel and gold grill cloth is changed to a polished aluminum look with silver grill cloth.

 

This is a dealer brochure from sometime in 1966 showing what the dealer paid, and what was suggested as a retail price. The nickname, "The Pulverizer" was light-hearted and aimed at a youth market.

 

Dating M15's

The earliest M15A schematic I've found has a release date of 3/23/65. This coinsides with the timeframe of the switch from the M15 to the M15A date codes I've collected. For more on this subject, see Dating Customs.

At Left:
This early 1965 catalog picture showcases the M15A Pro-Amp with two RS-3 remote speaker cabinets, and two Starstream guitars.

Schematics:

  • M15A Rev.A Mar/65
  • M15A Rev.F Oct/65NEW
  • M15A (no echo control. rev. unknown)
  • Schematics

    see schematics

    M2 M4 M6 M7 M8 M9 M10 M12 M13 M14 M15 M10A M13A M15A M20

    DA/MagnatoneAmps.com

     

     

    Except where otherwise noted, text/written content on this site is licensed under a Creative Commons Attribution 3.0 License.
    Creative Commons License

    web mechanics: text-to-html with Markdown, css handled with Blueprint, glued together with PHP