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Hi All,
So I just completed my build. When the pedal is engaged I have a volume jump but no phase effect is produced. Any thoughts… COMPLETE NOOB here so be kind 😉
Be sure you made both ground connections and check your trimmer adjustment? Not really a thought just guesses.
Some good clear & detailed photos of the build would give a better opportunity for us to better help.
Did you used a matched set of 2N5952 JFETs?
How about power supply and VB measurement values? What are those reading?
@brd – I did use both GND pads. I’ve also adjusted the trim pot. No change.
@CyberCow – I did use the match 2N5952 JFETS. As I mentioned… I’m really new at this. I checked the voltage @IC1 PIN3 and it’s reading 4.19. Not sure I’m doing this right. I see the VB points on the schematic. Do you know what the voltage should be? What’s the best way to test this?The Vb will vary depending the setting of TR1.
To measure the voltages on the ICs, you need to measure at their power supply pins.
IC1 PS pin = 7
IC2 PS pin = 4
IC3 PS pin = 7
Also, ensure the JFETs are securely seated in the sockets. If they wiggle, they’re likely not going to perform well. I like to gently wrinkle the ends of the legs so they are stiff going into the sockets.
OK, so your PS distribution is good.
The next thing to do is connect & fire it up in a way you can access the trimpot inside, put a signal thru it with the pedal engaged. Then with the trimpot set to center, ever so delicately, slowly and in very tiny increments, turn it it to the left to see if the “vibe” starts happening. If you get all the way to left, (again in very tiny increments), and there is still no ‘vibe’, set the trimmer back to center and start, very slowly turning it to the right, (and again in very tiny increments) till you get the ‘vibe’ sound. That trimpot setting is VERY delicate and there is a very narrow sweep point at which it will trigger the ‘vibe’ action. Be patient and delicate with the trimpot setting. The first time I built one, it took me a few minutes to find the sweet spot.
Let us know what happens after that.
@cybercow Boom… Thank you so much for your help. Patience is the key with that trim pot. It is very sensitive. Seriously though… thank you so much for your patience… and tips! I learned a lot through this troubleshooting exercise. I feel a lot less intimated than a week ago. I’m going to mount it in the enclosure and do some more tweaking with the trim pot dial it in just right.
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