Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 1blueheron on January 11, 2019, 02:47:11 pm

Title: Neon based relaxation oscillator circuit for tremolo effect?
Post by: 1blueheron on January 11, 2019, 02:47:11 pm
I the last two organs I have salvaged, I encountered some neon tubes or bulbs.  Curious as to there use I have been doing some research. 

The Conn organ used a A03 tube, the Baldwin has a section jam packed with miniature neon bulbs.  I believe the use may have been as the oscillator generator but I could be wrong.  I know the A03 is primarily used as a voltage regulator.  My question is, would it be possible to use a neon tube or bulb as the means of creating a vibrato or trem effect for a guitar amp similar to that produced in an organ.  I am attaching pictures of the neon section I removed from the Baldwin last night.  I believe the incandescent bulb is used as a light source to trigger a lower strike point for the neon bulbs.  This was inside the chassis and completely hidden from view.  It was definitely not any kind of visual indicator.

 
Title: Re: Neon based relaxation oscillator circuit for tremolo effect?
Post by: PRR on January 11, 2019, 03:43:49 pm
All them Neons are *probably* the Tone oscillators.

Musical tones should have harmonics. Often it is cheaper to be over-rich on harmonics and filter-down to the desired timbre. The alternative is fuzz-guitar- mellow string and distortion to add overtones. Musically these give different effects.

The output of a Neon is a Ramp wave. Sudden jump and slow recovery.

Tremolo is doors in front of organ pipes and a foot-rocker to open/shut the doors. The usual foot action is gradual open and close. Triangle or Sine wave.

Finally: the Neon oscillator is weak. You mix and filter a bunch and then amplify-up. The common Fender term oscillator is that amplifier, self-oscillating, with a nice waveform.
Title: Re: Neon based relaxation oscillator circuit for tremolo effect?
Post by: sluckey on January 11, 2019, 04:07:26 pm
Here are two low end Magnatone amps that use a neon relaxation oscillator in the trem circuit...

     https://el34world.com/charts/Schematics/files/Magnatone/Magnatone_mp1.gif

     https://el34world.com/charts/Schematics/files/Magnatone/Magnatone_mp3_5.jpg