Powering the Neovibe, (more complicated than the simple transformer question)

[sjaltenb]

OK so here is the deal.

The NeoVibe is going in my Cornish Board, where all the grounds are tied together through the power supply which is then grounded to the input/output panel through the sleeves. So the ground scheme is:

Input sleeve-->power supply (with a ground plane that all components are grounded too) with a ground out that goes to the FX PCB. It works perfectly for my situation.

OK, so, for the NeoVibe...I already have a 9V highly filtered supply that I would like to use for power. I have built a MAX1044 Charge Pump that I have 18.05V coming out. I can keep building it to 25V if I need to, (but I only have 15uf 50V caps, will those work?)

What I am thinking is this: Use the 9v (and respective ground connection...just like if it were coming in from a PP2) and go into the Charge Pump to get 18v (or 25). Shouldn't I then simply add a 15V regulator to the charge pump circuit, and make sure I get 15V regulated out of the charge pump under a load?

Now I guess the issue comes here: I would assume that I could just remove the diode bridge, the 15v regulator and I the filter caps, and simply "plug in" the 15V out of the regulated charge pump into where I remove the other regulator (the one on the neo). But how do I power the bulb then? Is there another place I should 'plug in to'.

Then what about the signal ground? Can i bring the ground in from the original ground that goes into the Charge pump? I guess the reason I am so confused is because of the way RG says DO NOT GROUND THE DC input!! Is this just because of the diode bridge there?

Thanks, sorry for being complicated. Great pedal, really want to make this work!

[R.G.]

OK, so, for the NeoVibe...I already have a 9V highly filtered supply that I would like to use for power. I have built a MAX1044 Charge Pump that I have 18.05V coming out. I can keep building it to 25V if I need to, (but I only have 15uf 50V caps, will those work?)

What I am thinking is this: Use the 9v (and respective ground connection...just like if it were coming in from a PP2) and go into the Charge Pump to get 18v (or 25). Shouldn't I then simply add a 15V regulator to the charge pump circuit, and make sure I get 15V regulated out of the charge pump under a load?

Yes, that will be OK as long as your charge pump does not sag to under 17V under load.

Now I guess the issue comes here: I would assume that I could just remove the diode bridge, the 15v regulator and I the filter caps, and simply "plug in" the 15V out of the regulated charge pump into where I remove the other regulator (the one on the neo). But how do I power the bulb then? Is there another place I should 'plug in to'.

The bulb will work OK from 15V, so you can remove the diode bridge, 15V regulator, and caps as you say, and connect 15V from another source to both the DC into the regulator hole in the PCB, and also the regulated output. Should work, although I've never tried that.

Then what about the signal ground? Can i bring the ground in from the original ground that goes into the Charge pump? I guess the reason I am so confused is because of the way RG says DO NOT GROUND THE DC input!! Is this just because of the diode bridge there?

My warning is because a number of people have tried to use this with the diode bridge in place, which makes both the power coming in be "grounded" and the signal ground as well, but power is still running through the bridge, and that's trying to make the two grounds be a diode drop apart.

In your case, remove the diode bridge and filter caps. Or better, leave a modest filter cap in there, maybe 470uF, for local filtering to help prevent noise. Then run your wires from the regulated 15 coming in to the holes left when you left off the second filter cap. A shorting wire between the input and output of the place where the 15V regulator would have been on the PCB finishes the changes.

[sjaltenb]

Thanks RG!

I think I may have blown out the bulb or the bulb driver as I had a bad trimpot and now it will not light...(even using my trusted solder iron to ground method  ...remember?) I replaced the trimpot and I get nothing. Will replace the bulb and driver and go from there.

Thanks so much for all your help! Hopefully I can get this thing 'Breathe'ing soon.

[sjaltenb]

Here is a thought.

I know you said the bulb would work properly at 15V, but I DO have the option at running it at 18 or 25V from the charge pump, by simply cutting the trace from the input of the regulator to the bulb...

Would 18 work better? Does it make any difference? Thanks!

[R.G.]

Here is a thought.

I know you said the bulb would work properly at 15V, but I DO have the option at running it at 18 or 25V from the charge pump, by simply cutting the trace from the input of the regulator to the bulb...

Would 18 work better? Does it make any difference? Thanks!

If you have a 12V bulb, chances are that 15V is fine for the bulb, and it's better for the charge pump because the charge pump has to process more power to get it up to 25V, and that voltage is then "wasted" down to 18V or 15V. So if you can get 15V from the pump and run it on that, it's better for the charge pump.

[sjaltenb]

I wired it into the 2nd filter cap and bridged the onboard regulator and it seems to be working great. I get 15.13 to all the transistors across the top of the board.

Now, after biasing, i get a very dull glow from the lamp, and controls have no affect. I get the 15V on the bulb, and about 13.5, 1.6 and .9 on the bulb driver. Must be something going on here....

strange, as I have not changed anything from before when it was working...at least I dont think... I'll keep troubleshooting. If i short the bulb driver i get full glow.

[sjaltenb]

I have created a new thread involving this debug.