Behringer Hellbabe Wah

[Dave Eason]

Hi Guys,
I was just wondering if any of you have any technical documents or schematics regarding this pedal - someone has given me one to have a look at.  It basically doesn't switch out properly, the effect is always on, yet when you open it up and have a look, as the "blade" attached to the treadle moves and unblocks light from one of the LEDs onto the LDR, the other LED lights, as does the staus LED on the front of the unit, telling me the optical switching works properly so it's either a FET or some comparator type issue i.e the switching signal is getting to the switching circuit but it aint doing it's job so to speak.

It's hardly worth the fix seeing as they're so cheap, but I thought I'd have a go!

cheers
Dave

[toneman]

There's one on ebay for 20bucks + shipping.
Zzounds sells them new, in a box for $26bucks + shipping.
Never heard one, but looks like they have several controls.
Shouldn'b too complicated circuit-wize...
got a jpg of the pcb???
probably all surface mount(?)
afn T

[Dave Eason]

yeah, I think it's a multiple layer SMD layout, not much too it really, couple of TL064's, two SMD fets and two pinned transistors, and a whole bunch of SMD resistors and caps, as well as a few electro's and an inductor.  I'm sure the switching is controlled by a comparator driving the FETs somehow, where the LDR output is used to swing the comparator output, but there's no adjustable threshold or anything like that.  A scematic would be good!

It's fine for the money really, the sound is OK, even if the range is a little small, but it is adjustable, with adjustable Q of the bandpass filter, and a boost feature which aint too bad to be honest.  There is a bit of a pop when it (used to) kick in and out, but the level doesn't really change, and it's fine for live use.. if a bit plastic-y.  Maybe some recycled heavier duty housing would be good.  And oddly for behriner it doesn't seem to be a direct cheap clone of something else.. it's like a morley/cry baby if anything (functionally and aesthetically.. not tonally!)