Using diodes for PS voltage drop?

[poboy]

I am working on an audio project that is requires an 18V max. power supply. I also have access to some surplus 20V laptop switching power supplies.

Is it feasable to use diodes in series (3 @ typical .7V drop = 2.1V) with the 20V supply to get 18V for the project?

Thanks.

[Tom Phillips]

I am working on an audio project that is requires an 18V max. power supply. I also have access to some surplus 20V laptop switching power supplies.

Is it feasable to use diodes in series (3 @ typical .7V drop = 2.1V) with the 20V supply to get 18V for the project?

Thanks.

That will work. However, I'm not a fan of using switching power supplies in audio equipment because of the higher possibility of noise they often cause.
Always a good idea to test your power supply with a load equivalent to your application, determine if it really puts out 20V and check the regulation.
Regards,
Tom

[Earl]

Diodes are used all the time for series voltage dropping...but I agree about the switching power supplies..they can be pretty noisey

[amptech]

Hi Tom,
depending on what equipment your pluging in to your power supply try using adjustable voltage reg's like Lm317T or L200 that adjust's both voltage and currrent to sute your need's.
amptech.

[Enzo]

And are there trimmers on the switchers? You might find 18v within the range of the 20v supply adjustment range.