Univibe issue - bulb not bright / deep enough flashing.

nznat

nznat

Member
Im having trouble with a vibe build. Here's the thing. When i plug in the power supply, i see the bulb go brighter and deeper in the flashing mode, seems perfect, yet after about 1 second after i plug in the power supply it suddenly goes more dim, the depth of the flashing has gone much dimmer / less, thus the lush univibe tone is mostly gone because of this, doesn't sound correct anymore. Any ideas on power supply issues on the pcb or what part of the univibe circuit controls the power of the bulb itself? Can anyone point to these areas and caps etc that regulate the bulbs depth of flashing on the schematic attached so i can remedy this situation?
much appreciate your help
 
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i have made three of the boards, all came out the same, soldering is fine. everything now working fine except bulb depth of flashing. just not deep and bright enough. Or thats what i think. the sound is more like a tremelo effect rather than a swealing lush vibe effect
 
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nznat said:
i have made three of the boards, all came out the same, soldering is fine. everything now working fine except bulb depth of flashing. just not deep and bright enough. Or thats what i think. the sound is more like a tremelo effect rather than a swealing lush vibe effect
Click to expand...
This is standard practice, saves the guessing game:

Important: Supplying Pictures when an Issue arises with a PCB Build !!!

I have to raise this ongoing issue when Members ask for Help with an Issue with their Build. I keep repeating this saying '' Pictures are worth a Thousand Words'' !!! Please supply Pictures of PCB & ALL connections ( Footswitch, Input & Output Jacks, Power Jack ) to it along with a clear...
forum.pedalpcb.com forum.pedalpcb.com
 
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Just attached my entire schematic. I dont need to send picture of board aswell as the soldering is the best of the best as its a SMD / Surface mount i got made at the factory, the soldering is perfect. The thing with the pedal is that it is working, all functions, but the vibe effect sounds like shit. more so like a bad tremelo, and i almost get there with the mini pot adjustment but it just doesn't get the deep and "swishy" sound. its flat and tremelo. Ignore the parts that are relay switching, as the pedal has two sets of pots to have dual settings.
 
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I don’t see a schematic here. Maybe I missed it. I know the time I had a similar issue with a vibe sounding like a tremolo my Ldr had too large of a spread. And the dark resistance was too high. I solved this by running a resistor in parallel.
 
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Big Monk said:
@nznat

We are just having a little fun with your predicament.

A few questions:

1.) Are you tuning the board with the light shield on?

2.) Which LDRs are you using?

3.) Can you tack in an offset control to the lamp driver circuit?
Click to expand...
Tuning with light shield on: YES
My LDR: PGM5659D
I installed an offset adjustment that replaced the 100k / 47k with a 250k pot.
 
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