stimbox - diglet48/restim GitHub Wiki

My stimbox was based on lolol2 design. It is now retired in favor of FOC-Stim.

Parts:

• TPA3116d2 stereo transformer. My sample is a chinese clone chip.
• elma TT IZ1892 transformers
• 3.9ohm serial resistor
• 22ohm parallel resistor (now removed)
• 12v PSU

I performed many measurements on this box.

• Characterizing the elma TT IZ1892 transformer.
• Measuring the impact of the parallel resistor.
• Testing different values for the series resistor.
• Multi-phase modelling: multi phase circuits

Short summary:

• Parallel resistor is useless.
• This amplifier + transformer combination is very linear, constant volume over wide range of carrier frequencies.
• ...but, nerve sensitivity and skin resistance depends on frequency, so changing the carrier frequency still changes the intensity.
• Characteristics of three-phase configurations change as the carrier frequency changes.

The tl;dr is that if you want to keep things simple, pick a constant carrier frequency.