AMZ Mosfet Booster - thump noise...

[jophus]

AMZ Mosfet Booster from tonepad -
http://www.tonepad.com/project.asp?id=30
Hi guys, dunno if any of you can help- this is my first project...

All went together OK, made up PCB myself, tracks all checked out fine- only difference is I used a 10k pot instead of a 5k, as it was all I could find at the mo. Oh and left off battery connector, I only run stuff from 9v powerpack.

Problem is this- loud thump noise when I press the footswitch. Only really gwt boost on last 5mm turn of the dial- I guess that'  s because  Ishould swap 10k for a 5k? But the big problem is the thump noise.

Any assistance greatfully appreciated!

[$uperpuma]

when I had this problem and read a post by Jack Orman saying NOT to put a pull down resistor on the front.   the Answer that worked for me came from thegentleman at Catalinbread... a Pulldown resistor on the output took the pop away completely 

[boogietube]

I built mine with the Tonepad layout and used the Milennium bypassing. No pop.

[Barcode80]

millenium bypass is a great circuit and cheaper to buy with a dpdt switch than it is a 3pdt switch, but the hassle of wiring up another circuit isn't for everyone. pulldown resistor is the answer.

[jophus]

Thanks for this guys-

I've made the circuit with th milenium bypass in it- I assume that is working ok, as the led lights up ;-) what size is a pulldown resistor? where exactly should I put it? literally the last thing on the board?

Thanks again guys!

[Barcode80]

you shouldn't need the pulldown if you use the millenium bypass 2.

[amz-fx]

The versions of the pcb that I sell have the pull-down resistor already  included. 

You should add 1M immediately after C4 on my schematic.

regards, Jack

[$uperpuma]

From the man himself. THAT is why I love this place. Thank you Mr. Orman.

[rpjones]

But I did build it on Jack's pcb as per his schematic and instructions, with the 1M after C4, and I still get a whopping thump when hitting the button. Now what?

[jophus]

yup, have the same problem...... |I get no wump when the circuit is turned off, but a loud one when it goes on. Also, the LEd remains lit throughout. I don't really get any variation on the effect from the pot either- the effect when it is on is way quiet. Seems hard to find a 5k pot in the UK- what is the effect of me using the 10k?

[jophus]

Hey rpjones

Looks like we've been forgotten- back to the drawing board I guess.....

Joe