Boosters and a no-good power supply

[ward]

I finished a Mosfet Booster, great clean booster !! 
THANK YOU, Jack Orman.

But I'm having trouble with my powersupply,
With a battery, the booster is silent, with the diy powersupply I made, it buzzes loud.
More or less the same noise I experienced on my 'sweet thing'
http://www.diystompboxes.com/smfforum/index.php?topic=48868.msg377198#msg377198

Now I can built some of the projects on the net like the ultra-clean power supply:
http://www.generalguitargadgets.com/diagrams/ultra_clean_ps_sc.gif
But, I'd like to understand what is wrong with my powersupply.
What I have is:

Powertransfo 18Vout
>> Bridge rectifier,
parallelled with a 3300uF cap and a led
>> 9V regulator
4700uF cap in parallel
to stompboxes.

What do you think, should it be improved ?  Or better built something proven ?
Thanks in advance for your opinion.

[petemoore]

  EZ Option...V.S. 1Spot adapter, Visual Sound. The Best Power Supply purchase I've made or heard of.

[ward]

I allready got transfo's lying around, so why not built it myself.
A powersupply should be easy enough.

[geertjacobs]

edit: mental note: I need to read first post better before posting reply 

[ward]

I checked some designs on the net,
and it seems to me that 85% doesn't go further than transfo > bridge rect. > large cap > regulator > large cap > out

Maybe my caps are silly large, but that shouldn't hurt right ?

What's your opinion ??,  am I drawing wrong conclusions in blaming the power supply ?
Or does it need additional filtering ?  Any other mosfet boosters out there that act buzzy with a simple regulated power supply ?

[geertjacobs]

I did a search on the Mosfet Booster and read that other people also had issues with the Mosfet Booster being sensitive for power supply ripple.
Another forum member suggested that this could be solved by adding an extra cap and resistor to filter out that ripple.
The AMZ Mini Booster Schematic incorporates this power supply filtering (100 Ohm resistor + 100uF cap).

[ward]

I'll check that out,

bedankt Geert

[amz-fx]

I did a search on the Mosfet Booster and read that other people also had issues with the Mosfet Booster being sensitive for power supply ripple.
Another forum member suggested that this could be solved by adding an extra cap and resistor to filter out that ripple.
The AMZ Mini Booster Schematic incorporates this power supply filtering (100 Ohm resistor + 100uF cap).

The pc boards  that I sell for the Mosfet Boost already incorporate this type of power filter.

regards, Jack

[d95err]

Some ideas: (I'm certainly no expert on these matters)

Try pre-regulation to make the input to the regulator closer to 9V. E.g. using a 12V zener.

Many power supply designs have much smaller caps on the output. Sometimes a small cap (e.g. 0.1u) us used in paralell with a larger electrolytic cap. This is (I think) because large electrolytics can have high impedance or something. Anyway, the smaller cap may be better suited to handle small ripples.

Computer gear (hubs, switches, network cards) need heavy power supply filtering. If you scrap an old broken switch you can often find nice power supply filter inductors in them.

I think there are several articles on power supply filtering over at www.muzique.com. Check the lab notebook.

[ward]

Thanks guys,

Much better now with 220ohm and a 100uF cap.