Simple Road Rage Question

[ddavis20341]

Quick question about the Road Rage, just to make sure it can do what I'm asking.

I want to use a road rage (or 2, if need be) to replace the power supply for my Deluxe Electric Mistress (a 24V center-positive wallwart). It says in the build doc that the inverter and charge pump can be used simultaneously, so am I correct in thinking it can take in a 9V or 12V center-negative and output 18V or 24V center-positive to the circuit? Or would I have to daisy-chain 2 Road Rages together, one doing each part of that?

If anyone can walk me through how to do all of this, that would be great. Thanks!

[WormBoy]

Center positive/negative only relates to the plug you use to power it, and nothing with the circuit itself. Positive/negative ground is more important, but this is a regular negative ground circuit. So you can just use one road rage to get you 18 or 24v. If you power it with 12v, make sure the voltage doubler chip can handle it, and make sure that the voltage rating for the caps (particularly C4) is high enough.

Oh, and check current consumption of the circuit. I guess you will have to use the LT1054 as you will need the extra current. Also, you may want to check the schematic for your version of the mistress: the input is regulated down to 12 or 15v anyway in the mistress, so feeding it with 18v (and thus powering the road rage with 9v) may be enough.

[Zigcat]

Also, you will not need the two rectifier diodes on the pcb that feed the 12v regulator on the EM. Road rage at 18v fed directly into the regulator should work.

[ddavis20341]

Awesome! Thanks for all the help. Can I ask why they use a 24V supply if it's knocked so far down in the circuit then? (unless I'm completely misunderstanding)

[WormBoy]

Maybe they could get them for cheap ... or it is a protection against major fluctuations in the mains voltage ... or the circuit draws so much current that the voltage supplied by the wall wart sags ... I really don't know. However, as the entire circuit lives behind a voltage regulator, you only need to make sure that you supply the regulator with a constant high-enough voltage so that the regulator stays happy 

[Zigcat]

Maybe they could get them for cheap ... or it is a protection against major fluctuations in the mains voltage ... or the circuit draws so much current that the voltage supplied by the wall wart sags ... I really don't know. However, as the entire circuit lives behind a voltage regulator, you only need to make sure that you supply the regulator with a constant high-enough voltage so that the regulator stays happy 

Truth. And, EH was known for doing things as cheaply as possible, so perhaps they were just keeping costs down by using the same transformer as used in the Memory Mans. They did utilize a voltage greater than 12v.