LPB-1, Why yes another problem.

Started by Kwagmire Wagner, October 03, 2014, 07:09:47 PM

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Kwagmire Wagner

Hi folks, I am trying to build my first pedal from this schematic:

http://www.beavisaudio.com/schematics/Images/Electro-Harmonix-LPB-1-Booster-Schematic.png

and have used this pin configuration for the 2N5088:

http://pinout-circuits-images.dz863.com/28/2N5088.jpg

I have successfully hooked it up to a DPDT and a 100k pot. Everything works fine except...

... there's no boost given. The pot works fine but it only reaches unity and it creates a tone difference. I've switched the transistor around and it makes no difference. My voltages all look good from what I can tell. I'm totally baffled.

induction

Post some pictures: hi res closeups of the front of the board, back of the board, and wiring. Voltages would help too.

vigilante397

Quote from: Kwagmire Wagner on October 03, 2014, 07:09:47 PM
The pot works fine but it only reaches unity and it creates a tone difference.

Not exactly what I call "working fine" :P As mentioned pictures of your board will help us help you :)

Welcome to the forum by the way ;D
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anchovie

Quote from: Kwagmire Wagner on October 03, 2014, 07:09:47 PM
The pot works fine but it only reaches unity and it creates a tone difference. I've switched the transistor around and it makes no difference.

If switching the transistor makes no difference then you've got an error somewhere that stops it from being an amplifier, hence the pot at max gives unity.

Also give us actual voltages and the layout that you're working to when you post the board photos.
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CodeMonk

I had a similar problem a week or 2 ago.
In my case, it turned out I had wired the DC jack backwards.
Check that.