I've just bought an SM82 from the US, and got it for good money ($50 inc shipping) Obviously the PSU it came with is for 110v power so i've gathered together all the bits to make my own 230v PSU. they do sell reproduction PSU's on EBay but they go for around £50 and I can make one for around £20. i do have quite a bit of experience with soldering and electronics, but NOT with PSU's, never made one. But it's one of those things i want to have a go at to tick off the bucket list of things to do.
A guy previously made one and posted his build on another site (I've also posted on that site to try and gain more information) his build is here https://www.thegearpage.net/board/index.php?threads/diy-rane-rs1-power-supply-for-sm26-and-sm82.1838728/
he built his with no thermistors in series, which i don't want to do, I want to play safe.
I've purchased a transformer from Rapid Electronics (Vigortronix VTX-120-5412-209 PCB Transformer 230V 12VA 9V+9V) which should do the trick, but my question is around the thermistors. The PCT Thermistors are there to prevent inrush current into the transformer so i'm a little loath to build this without thermistors in place.
The schematic for the original PSU is not available, however there is a schematic for a Rap 10. The Rap 10 is the same as the single PSU, just multiplied 10 times, so please ignore the other 9 outputs on the schematic.... Here is the schematic https://www.ranecommercial.com/legacy/pdf/old/rap10sch.pdf
As the thermistor is variable resistance how do i know what one to buy?? Is there a way of calculating the zero power resistance? Rapid have the following on their site
https://www.rapidonline.com/Catalogue/Search?Query=thermistors&Tier=PTC
Any ideas??
