Capacity and Suitability of this PSU?

DIY STUFF
1

Hello folks,

I’m looking at options for my first foray into Eurorack and have been looking at power supply options.

The TipTop Audio Uzeus PSU and Frequency Central DIY PSU are high on the list but my question relates to a power supply I already have and whether this might be a good candidate.

I have an old active crossover that I was given a few years ago, it never sees any use. I was actually going to salvage the case and use it for another project. Looking inside I found there is a linear PSU that was setup to put out +/- 15V.

The PSU board has an LM317 with a large heatsink for each rail and a single 4700UF cap for each rail. The A/C transformer feeding the board has an output of 20V AC at 0.875A capacity. There are of course Bridge Rectifier Diodes on the board also (AM152 - 1.5A). I checked the spec sheet for LM317 and changed the appropriate resistor so it is now putting out +/-12v on each rail.

My question here is how would the capacity of this PSU compare to the TipTop Audio Uzeus PSU (1000mA +12v 500mA -12v) and the Frequency Central DIY PSU (500mA at +/-12V). I’m a little unsure how to calculate this? Is the transformer a bit on the small side (0.875A @ 20V AC)?

I would be looking at building a 104HP 3U case.

many thanks.

2

Sounds like an ok supply, at least up to 400 mA or so.

Not an LM317 and an LM337?

Also, does the transformer have a center tap?

2 Likes
3

Well… LM317 & 337 are adjustable so if there’s little preset potentiometers you may be able to adjust them to +/- 12V. 400ma a rail should be enough to get you started to see if it’s something you’ll be interested in.

I started out with the FC DIY board and a 1.5A transformer. Within a month i’d built and added enough modules that the wobble became totally unacceptable (but also have a couple of very power hungry modules… a Midimuso, and an Expert Sleepers ES-8, as the whole idea starting out was for my wife to be able to do hybrid synthesis)

Now we upgraded to this puppy that does 3.4A per rail. https://www.digikey.com/en/products/detail/bel-power-solutions/HCC15-3-AG/1634188