Build Your Own Clone Message Board

I just finished my classic phaser build, and I'm stumped. Everything looks pretty good to me, but it's not functioning. When bypassed, there is regular signal. When turned on, same exact thing. It turns on, the LED works, everything functions like normal except there is no phaser effect happening. At first I realized I used the wrong value trimpot (25k), so I swapped it out to the correct 250k, but that made no difference in sound. Even when I turn the trimpot, there is no difference at all in the sound. Any help is greatly appreciated! Thank you! (I'm not sure if any of the pictures uploaded, I can't figure it out, any help with that would also be greatly appreciated!)

If you turn the trim pot all the way left and then all the way right, does the sound change? If so, the calibration sweet spot is about a millimeter or two, so you have to go super slow when calibrating.


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Pedal building is like the opposite of sex. All the fun stuff happens before you get in the box.

You can use the file attachment function here in the forum, located just below the message editing box. Click on the "Choose File" button, browse to the photo location on your PC or phone, and then on "Add the file". The file size limit for attachments is 1 MB.

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

No the sound does not change at all. I went super slow and there still doesn't seem to be that sweet spot, it would be a very noticeable difference, right? My trimpot only has 3 legs where the board has 5 holes. I put the legs in the top 3, leaving the bottom 2 exposed, is that correct?

Figured out how to add the pictures, thanks for the help! Here's shots of the front and back!

Yes, when you hit the sweet spot, which should be pretty close to the midpoint of the trimpot sweep, you should get that characteristic phaser "warble."


Yes, that's correct. The bottom pair and the middle pair of eyelets are connected on each side; this is to accommodate different makes of trimpots that differ in their leg spacing.

I would suggest testing the function of the trimpot. Disconnect power from the pedal and use a multimeter set to the resistance mode for this purpose. Start by measuring the resistance between the legs on each side; this represents the full resistance range of the trimmer and should be close to 250 Kohms. The set the trimmer as close as possible to the midpoint of its range and measure the resistance between either of the side legs and the middle leg. This value should come up close to 125 Kohms.

BTW, what's purpose of the resistor and wires connected to the LED solder joints on the back of the PCB? Are you providing power to the LED directly rather than going through the DC jack and the PCB? If so, why?

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thank you for the help! Sadly I don't have a multimeter so I can't do the test you mentioned. The resistor is for the LED, to dim it. I don't know how to read schematics, so I don't know which resistor on the board goes to the LED, so I just add the extra resistor to dim the light. Janky hookup, but it has worked so far haha. Do you have any other inklings as to why there is no phaser effect, or to how I could check for what's wrong? Thanks!

The current-limiting resistor for the LED is the 4.7K right beneath it on the PCB. There should be no need for additional resistance being applied there.


I have several other diagnostics that you could try, but they pretty much all require a multimeter. This is an essential tool for pedal building, so I strongly suggest you pick one up. If you have a Harbor Freight store nearby, you can get a serviceable unit for less than $10. Or there's always Amazon if you prefer to buy online.

Here is something you can try in the meantime, but your soldering looks quite good, so it very well may not help. Couldn't hurt, though: viewtopic.php?f=9&t=52188

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2