JFET Circuit Tutorial Needed. Where to Find?

[pedalpusher]

Ok I'm trying to find the problem with a KOTB 7 knobber. I need to know where I can find the info to educate myself on how to know what should be going on with the power supply. The pedal works great with an aux power supply but sounds like the battery is dying when I use one. The battery is fine and I get 9.6 volts either way all the way to the trannys. The exists when either the OD or boost is engaged. Preferably something free on the net since money is really tight right now. Thanks.

[aziltz]

Ok I'm trying to find the problem with a KOTB 7 knobber. I need to know where I can find the info to educate myself on how to know what should be going on with the power supply. The pedal works great with an aux power supply but sounds like the battery is dying when I use one. The battery is fine and I get 9.6 volts either way all the way to the trannys. The exists when either the OD or boost is engaged. Preferably something free on the net since money is really tight right now. Thanks.

from what you've said it sounds more like a current draw issue (causing the battery to sag, but not the Power Supply) and not necessarily a JFET issue.

I could be wrong.  Just my two cents.

[R.G.]

Ok I'm trying to find the problem with a KOTB 7 knobber. I need to know where I can find the info to educate myself on how to know what should be going on with the power supply. The pedal works great with an aux power supply but sounds like the battery is dying when I use one. The battery is fine and I get 9.6 volts either way all the way to the trannys. The exists when either the OD or boost is engaged. Preferably something free on the net since money is really tight right now.

Going off and learning the basics of JFETs, while an admirable thing to do, is a little like studying how iron is smelted from iron ore when you need a car. 

What's going on with the power supply is not particular to JFETs. Either it can supply enough current not to sag under load or not.

I'm having trouble deciphering "...sounds like the battery is dying when I use one. ... I get 9.6V either way all the way to the trannys". Does that mean you get 9.6 V with either power supply adapter or battery? Or that the battery is 9.6V when used either polarity?

The simplest thing for you to do is to read "What to do when it doesn't work" and follow those directions.

[pedalpusher]

Ok I'm trying to find the problem with a KOTB 7 knobber. I need to know where I can find the info to educate myself on how to know what should be going on with the power supply. The pedal works great with an aux power supply but sounds like the battery is dying when I use one. The battery is fine and I get 9.6 volts either way all the way to the trannys. The exists when either the OD or boost is engaged. Preferably something free on the net since money is really tight right now.

Going off and learning the basics of JFETs, while an admirable thing to do, is a little like studying how iron is smelted from iron ore when you need a car. 

What's going on with the power supply is not particular to JFETs. Either it can supply enough current not to sag under load or not.

I'm having trouble deciphering "...sounds like the battery is dying when I use one. ... I get 9.6V either way all the way to the trannys". Does that mean you get 9.6 V with either power supply adapter or battery? Or that the battery is 9.6V when used either polarity?

The simplest thing for you to do is to read "What to do when it doesn't work" and follow those directions.

Thanks R.G. What I mean is I get 9.6v with either a battery or an adapter. It sounds sputtery and has little volume with a battery but sounds fine with an adapter. I figured it was a current draw issue. How would I figure out where it's being drawn from? Should I just check the voltage drop across all components involved? I'm busy doing home projects today but will be able to get to it later or tomorrow.

[R.G.]

If you think about it, the difference has to be reflected in the DC voltages. If the bias points were the same, then the operation would be the same.

Check to see that the battery input has a decoupling capacitor connected.