Modify SMPS with dual rails to single rail?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi folks


I bought an old fibre network thing to repurpose the 1U case to house a phono preamp.


However, inside I found a rather nice pair of SMPS, each appears to have a pair of +13v rails and a pair of Grounds.


Now, I'm thinking, this could make a rather nice dual supply - one SMPS for each of the left and right channels.


Is it possible to hook up these supplies to produce a 26v single rail that I could then drop using a regulator to the 18v my preamp board needs?
 

Attachments

  • DSC00212.jpg
    DSC00212.jpg
    213.4 KB · Views: 205
  • DSC00213.jpg
    DSC00213.jpg
    294.8 KB · Views: 162
  • DSC00214.jpg
    DSC00214.jpg
    365.9 KB · Views: 161
  • DSC00217.jpg
    DSC00217.jpg
    391.3 KB · Views: 160
  • DSC00214b.jpg
    DSC00214b.jpg
    256.2 KB · Views: 148
I found a switch salvaged from some old piece of equipment in my box of bits that happened to fit perfectly in the hole the second power socket occupied (each SMPS board had it's own socket) and a ferrite ring with some heavy duty mains cabling threaded through it so I wired up both SMPS boards to the single socket via the switch, placing the ferrite ring between the socket and switch. I used some yellow heatshrink to make sure all the dangerous voltage bits are well insulated.

Total outlay on this project so far is 4.19ukp - the fibre switch cost 99p on ebay with 3.20 postage, the switch and bits of wire with ferrite ring I found in my stash.

I'm not sure what I'll use this enclosure for, maybe a DAC or headamp that only requires 12v supplies.
 

Attachments

  • DSC00218.jpg
    DSC00218.jpg
    261.1 KB · Views: 62
  • DSC00219.jpg
    DSC00219.jpg
    294.9 KB · Views: 48
  • DSC00220.jpg
    DSC00220.jpg
    306.4 KB · Views: 43
Last edited:
Hi Nigel, always good to hear from a fellow Cumbrian, I hope the weather is as nice and sunny up in Carlisle as it is down in Millom.


This thing has three earth points, one for each SMPS and a third at the front below them that was connected to the mainboard I removed.


Pardon my ignorance, but how would I do that buzz test?
 
I've been delayed by having to repair my speakers, but tonight I got the DMM out to test the earth connection. Unfortunately, when I flipped the power switch there was a crack and some blue sparks from the back of the switch. No disgn of any scoring or burning, I think there must have been a short, perhaps in the switch itself as I am positive my wiring was correct.


So I decided to go to plan B, I ripped out the power switch and both SMPS units, I am replacing them with a pair of toroidals, a pair of rectifiers and some linear regulators.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.