Is it me, or a LM317 PS is not the best choice to feed a 1w to 3w smal amp?
I've been using my 9v and 18v LM317-based PS for decades to experiment with pedals, they are as quiet as a Carl Martin PS I also have.
But recently I noticed that when I used them to power up a small amp like a Deacy on steroids I get an annoying, tiny distortion more noticeable when playing two notes in the middle of the freatboard using single coils and the amp set to clean (like intermodulation in Class B or a hi-freq sawtooth mounted on the signal, can't find the right words).
I always blamed the breadboard, the planetary aligment, the Gov, etc.
I took for granted that the venerable LM317 is king...
Yesterday I was playing with a Class A BJT+OT at 200ma idle,18v LM317 PS.
After an hour of tweaking here and there to get rid off the distortion I stopped for a while. For no reason, after a few seconds my eyes fell on the PS... "what if? naaa, can't be!... it's been built with good filtering, heat sink, and never had noise issues with high gain pedals... but these pedals do not suck 200ma or more..."
I took an old 220v - 12v used for dichroic lamps, added a rectifier, fired up... the annoying distortion was gone.
So...
Both power supplies have a defective filtering, leaky caps, etc,
or under pressure the LM317 is a bit noisy.
Thoughts?
mac