One PSU to rule them all!

[frasco]

As I've just started on the path of building amplifiers - the first one is (hopefully) soon finished and the second is at the planning stage - I realized that as all of them need a power supply - which can easily be the most expensive part of the amp - and I obviously only use one amp at a time, it would be very convenient to have just one power supply which would work with most of the projects.

So the question is, if you had to live with just one power supply, what type would you build and why? Type, volts/power etc.. I'm mainly focused on chip amps at the moment but I'm also interested in building tube amps in the future, are there any specific differences between those respective PSU's?

[twest820]

Yes, there's a difference between supplying several hundred volts at a few milliamps and few tens of volts at a few amps. Easier to have multiple specific supplies than one configurable one.

[tvrgeek]

The power supply is actually a critical part of the audio circuit. It by definition is in series with your outputs. Detail design, and I mean both physical and electrical, can make or break an amp be it solid state or tube. Why do you think Bryston's sound so good ( or basically, have no sound of their own). Physical design attention to detail! Yea the supply is expensive, but it is half the amp. As tw said, a 6v filament supply and 380V B+ sure is not the same as a 40V chipamp supply. Best do a bit of reading on the subject. ( Actually a tube amp, the supply can be more complex and expensive than the amp by a lot. ) Believe me? My headphone amp is one chip and about a dozen resistors for a cost of maybe 12 bucks. The power supply is is a remote box with the electronics on a 8 x 6 inch board and the parts cost well over 100. Yes, it sounds cleaner and more detailed than a pair of 9V batteries.

[AndrewT]

For experimental work and testing of a part built project, a universal supply is very useful.

Most chipamps will take +-20Vdc and will switch on and operate properly at this low supply voltage.

You could use a 100VA, 15+15Vac transformer feeding a bridge rectifier and a small bank of smoothing capacitors. This will need a mains fuse and secondary fuses to help prevent damage when inevitably you connect something wrongly.
I would also suggest you have it permanently fed via a Bulb Tester to detect and save mis-wirings.

If you want/need lower DC voltages then either extra transformer windings or chip regulators could give an unlimited range of fixed DC outputs. 4mm output sockets on the front panel to feed projects. Light bulb and ON/OFF switch on the top.

The final integrated PSU must be designed as part of the project. It must not be considered as an "add-on".

[v4lve lover]

what about a simple +-35 volt supply from a bridge and some caps . whit fuses mounted on the front . or overcurrent protection and a

variable part where you take the 5 amp LM338 and the negative counterpart and use that to supply a regulated output . and some pass transistor as a current limiter

then + and - 15 volt rails might come handy 7815 7915
12v 9v 5v

for tube audio look at some sweep tube regulated supplies

[eem2am]

One audio power supply to rule all.....just use a flyback.like this 500W flyback example which is 91% efficienct.........

500W SMPS for audio

Flyback gives you..........

- great transient response
-coupled inductors for the split rails are in the topology so no external inductors
-cheap
-No high side drive
-no current sense transformer
-no problems with staircase saturation as in bridge


So your answer is flyback for all audio supplies, regardless of power level......unless you have very tight size constraints, then youll need something else.