Discrete FET Guitar Preamp poping like crazy

[chemman]

I built the Discrete FET Guitar Preamp at http://www.till.com/articles/GuitarPreamp/ .

The transistor is biased properly and sounds good but I get a large pop when switching between pickups. I tried 3M ohm to 10mOhm across the input to ground with no difference. Any ideas?

Thanks,
Matt

[chemman]

I forgot to mention. When I turn down my volume pot for the pickups the sound cuts off after 1/8 turn and its very noisey. The voltage readings are 5.5 to 4.5v on the drain when turning the pot.

[syndromet]

I made it from the layout on my site, and it worked perfectly. No trouble with the volume controll. I dont have a pickup-switch connected for it, so I don't know about the poping.
Did you bild it on perf, vero or pcb?  Have you checked your soldering connections? Substituted any parts?

I would tripplecheck your layout up against the schem to see if everything is allright. It would be easier to find mistakes if you post a picture.

Hope you get this to work, as it's a nice, little circuit. It sure did wonders for my piezo-strat.

[Gilles C]

I am wondering about a few things.

Did you just connect the FET circuit after the volume pot of the guitar as we normallly do? Or if you inserted the FET preamp before the volume and even before the pickup switch?

If you just added the FET preamp after the volume pot of your guitar, the Drain voltage has nothing to do with the pop. And you should not have any voltage at the Gate to cause this pop.

And if so, did you check the voltage at the Gate of the FET?

If you inserted the FET preamp before the volume of the guitar or something like that, that's another story.

Gilles

[chemman]

Sorry guys I am a noob. Ok of all things the power polarity was reversed. Red of my wire was -  on battery.

With humbuckers it boosts more than 3db but I am using a different JFET (2n5457). Sounds nice and pushes my amp like crazy.

-matt