Introduction

This power supply offers a unique feature set for making high quality audio systems:

• low noise outputs (see datasheet and manual)
• power fail detection (to allow output muting to minimize click and pops)
• power holdup (to allow the controller enough time to mute)
• analog supply control (to make click and pop free power up easier to achieve)

You might like to assemble your own system, but building things with SMT parts is more than you want to tackle. The basic version is if you have the other parts and/or want to do something different than the standard +3.3 and +/-15 V outputs.

There's a second version that include all of the through hole parts with the board, so you can just build it without having to order parts.

If you just want an assembled and tested supply please see the Clockworks website. The two MTA cables are also available here as a convenience; it's pretty easy to build them but it's even easier just to buy them ready to go.

While we could ramble on about how great this supply will be for your application, we encourage you to look at the product documentation and decide for yourself. We're pretty confident that the feature set and the test information makes this a pretty unique option in the huge world of power supplies.

Hey, wait, this thing isn't...

$5? yeah, it's not built with a ripped off linear regulator chip where the chip maker didn't even bother to write their own datasheet. It's based on switching regulators which have much higher efficiency than linear regulators, meaning it runs cool. It also doesn't need massive capacitors for filtering.

It is open source, with the design documentation available under a CC BY-SA license so that you can copy and modify it as much as you want.

Switching regulators in an audio supply?

It's not 1985 anymore. Switching regulator noise is way outside of the audio band and at very low levels. The design includes a second LC filter stage to further reduce supply noise. With very light loads there is a chance of the noise ending up in audio band as switchers fall in to a power saving mode and run in bursts. But even then it's at very low levels.

We've tested this supply (see the Technote section of the Clockworks website) with op-amps circuits and noise from the supplies only shows up in circuits with a theoretical SNR of higher than 120 dB. If you're trying for better than that you'll need special low noise LDOs as well as op-amps that are incredibly low noise, as well as incredibly expensive. For use with something like 5532 class of parts this supply offers a good tradeoff in price and performance.

Cables

If you order the triple output supply and want the cable set please select it as an option when you place the power supply order, as the shipping charge will cover the cables, and we give you 10% off on the cable assembly. Buying it later/separately the system will charge a 2nd shipping amount.

12V DC in supply

A huge headache with transformers and linear supplies is supporting world wide operation across the 100V to 240V AC 50/60 Hz range. There's also the safety/liability of bringing line voltage inside of your system. While using an external brick has its downsides, there's an awful lot of advantages to doing that.

This supply has both a standard center positive 2.1mm barrel connector for a stock supply, as well as a 2 position screw block. The power switch has a parallel set of holes that can be wired to an external switch.

Unfortunately the commonality of the supply bricks also leads to a race to the bottom in terms of performance. In addition to supply noise on the rail and ground lines, there's conducted emissions that can occur that can show up as ground noise when connected to a larger system. Medically rated supplies generally have better datasheet performance. Even within a vendor the same supply in terms of voltage and current can change due to design updates.

Clockworks has tested a number of supplies and currently uses a CUI SWI18-12-N-P5 (different suffix types can denote AC plug option). It was tested and found to not degrade the measured supply noise. However we've tested other supplies that work, and some that don't. There is a secondary issue that the hold up cap causes some supply's protection circuit to trip. You can probably use whatever you have sitting around and be fine.