Univibe Power Supply with Road Rage Charge Boost 9 volts --> 18 volts

[franblanc]

I have constructed a Univibe clone using the attached schematic which uses a recommended 24 volts DC. The design seems to be a forumvibe but which version I am not sure. Some of the caps are rated at 25 volts so this seems a small margin of error. I want to use a Road Rage charge pump to boost my pedal board voltage from 9 volts to 18. The Road Rage 2019 uses an LT1054CP charge booster to amplify the 9 volts into a higher rating with no audible whine noise.
I have constructed the Road Rage and it works, I have 16.8 volts running into the Univibe. Now the Univibe lamp works, it pulses and the rate of pulse is successfully controlled by the speed knob. The intensity of the bulb is successfully controlled by the intensity knob and the volume works too. I know this because the guitar is audible on bypass and I also hear guitar when the Univibe effect is switched on at the footswitch however there is no Univibe swirling or whooshing effect.

I think I am close to a successful project. I suspect if I remove some of the 50 resistors I might achieve enough power to make it work. The question is which ones? I know that the Forumvibe design has worked with the road rage charge pump before, although the details are not clear to me. The LT1054CP has a max rating of 100 milliamps and I suspect this is where my problem lies as most of the Forum Vibe designs pull 150 milliamps. I have seem Univibe pedals from Jam or Rockett that use 9 volts so it should be possible. I am guessing how to proceed. Any assistance would be gratefully received.

[Redhouse]

Hello franblanc,

This is an old thread, but I came across it recently while updating my Forum-Vibe FV-5 docs, did you ever get this resolved?

If not, I have a few insights as to your power problem, but first I must ask if the vibe in the picture you attached is the one you are working with?, if the pic is the one you are working with you should know that is not a Forum-Vibe PCB, just sayin'.

Anyway, regarding the power issue, any normal/average Uni-Vibe circuit's power requirement depends on a few  things in your build, like what Lamp/Bulb you are using in your LFO/Bulb-Driver circuit. Most of the small Lamp/Bulb types are averaging from 40mA to 60mA operating current, and although we don't operate our Lamp/Bulb at full power in the vibe's that is still a fairly big chunk of a 100mA power supply.

If we were speaking of the audio section (w/o LFO and Lamp) of a vibe it can work quite fine on a 100mA power source and have some headroom, but when you add on your particular Lamp/Bulb to you power requirement things start to add up, for instance if your build has included an LED (or two) for indicators, then you will have added another 16mA-30mA to your 40mA-60mA that your Lamp/Bulb can require so now we're looking at 50mA-90mA level power requirement and we haven't added in the audio part of the circuit yet, but when we do add it all up we quite likely have exceeded the comfort-zone of the LT1054.

Anyway, I saw that no one replied on this so I wanted to give you some food-for-thought if you were still struggling, hope you got your build going since you posted this so long ago.