Neovibe power supply 15vac vs 18vac

[Greg]

I've gone through my second AC walwart on my Neovibe and need to order another one. I've previously used a 15vac 400ma from Mouser. Any reason I can't use an 18vac? Would it affect performance in any way? Better? Worse? No difference? Just seems I remember reading something about the original running on 18 volts. Could've dreamt that though! :roll:
Also, any other sources for one of these (15 or 18) besides Mouser that you could recommend? Might there be somewhere local that I could find one? I remember not being able to find one at Radio Shack. At least the 15vac type anyways.
Thanks for any info,
Greg

[SteveB]

While I can't direct you to a specific electronics source, I can tell you that I use an 18v adapter that was originally used for some sort of Peavey gear.  I got the first one at the local music store sometime in 1996. That one went out a few years later, & I got another one, which is still working today.

I have no idea what it was an adapter for, but the local Peavey dealer had quite a few of them around.

Hope this helps,
Steve

[R.G.]

18Vac will be OK. That will give you (18*1.414) - 2*0.7 = 24Vdc after rectifiction. The 15V regulator will be OK. It may put some stress on the lamp driver transistor, which was a weak spot in the original univibe. You might want to put a resistor in series with the lamp to make it easier on the driver transistor. 100 to 330 ohms  will work, but it'll need to be around 1/2W dissipation. That half watt, by the way, is what's NOT being dissipated by the transistor, which is what you want. Two 100R 1/4W is about right.