Superultra 205 Tig Pedal

[Rambozo]

Another route instead of an op-amp would be to just add an adjustable LDO voltage regulator to lower the incoming 2.7-5 volt reference voltage. Then you would use the max power pot to adjust the voltage. That would not require a power supply and you could switch it out of circuit at the max setting so you would not have any drop out voltage issue. There would a very small step near max power, when you switch it out, but the rest of the range would be totally linear. I bet the whole circuit would be $5 -$10 tops and simple enough to do on perfboard or even point to point on the back of the pot.

Of course just running on 120 for low range and 240 for high range is all I've ever needed, as I don't tend to work with the pedal "floored", but I know some people prefer that.

[joshuab]

Another route instead of an op-amp would be to just add an adjustable LDO voltage regulator to lower the incoming 2.7-5 volt reference voltage. Then you would use the max power pot to adjust the voltage. That would not require a power supply and you could switch it out of circuit at the max setting so you would not have any drop out voltage issue. There would a very small step near max power, when you switch it out, but the rest of the range would be totally linear. I bet the whole circuit would be $5 -$10 tops and simple enough to do on perfboard or even point to point on the back of the pot.

That's pretty clever. Goes to show how you should always solve the real problem (my max-output knob is non-linear), not the thing that is causing the problem (one pot is loading down another).

[Jeff9]

That's pretty clever. Goes to show how you should always solve the real problem (my max-output knob is non-linear), not the thing that is causing the problem (one pot is loading down another).

Joshuab & Rambozo,

Thank you for the responses. Very cleaver on both your ideas and work! So, if purchasing a higher end pedal won't solve the upper end control, I'll just learn to work with what I have. I really like the 160STH and the value.

Kind regards,
Jeff9