Tube Amps / Music Electronics
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|12/13/1999 5:31 AM|
||Problem with Millenium Bypass|
I have encountered a Problem with the Millenium Bypass circuit, I have installed it in a fuzz face clone, and it worked fine until the other day when the LED just started coming on slowly, it takes anout 20secs then fades in, I have used all the reversed components due to the fuzz face being a PNP type, so I don't under stand...
Can Anyone help me
|12/13/1999 8:38 AM|
i hate to start off stating the obvious, but assuming that your fuzz face circuit has a (+) ground, did you build the Millennum I bypass using an N-channel JFET or a P-channel JFET?
for (+) grounded circuits like the fuzzface you'd need to build the P-channel JFET version, while the (-) grounded effects require the N-channel JFET version.
|12/13/1999 8:48 AM|
I used a P channel JFET, as I said it worked fine and then just stopped,
|12/13/1999 8:56 AM|
well, so much for my bright idea.
now that i'm chewing on a foot sandwich my only recommendation would be to build another one and swap it out. its always easier to debug the first one after its out of your box. i would begin looking for obvious things like broken solder joints, lame components, etc. sorry i couldn't be more helpful.
|12/13/1999 8:25 PM|
The slowly-slowly symptom says that either teh connections/components to the JFET's gate are sick, or it's teh JFET itself. Look for a very leaky cap or a damaged resistor charging the cap.
|12/13/1999 9:38 PM|
Cheers I look at that, This was the sort of answer i was hoping for..
|12/13/1999 10:31 PM|
If you are using a diode pullup to the jfet, then changing to a different 1N914 might allow more leakage and a more positive switch action. The slow turn-on is fairly common with the jfet version and you can add a resistor across the LED to help eliminate this effect. Start with something on the order of 10k and see how that works then go down to 4.7k if you need more.
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