Anyone built the Maglev? Can't get it to modulate.

[gordo]

I can't get no...modulation...

This thing sounds really nice except no mod.  I've royally buggered up the rate pot pads in all my troubleshooting but to no avail.  Part values are good and swapping out the chip hasn't helped.  Any ideas?  The mod section looks really straight forward too.

[Bio77]

Is the light blinking?  Maybe it's a job for the scope.  I looked at the schematic and it seems pretty straight forward.

[matmosphere]

Did you get the two jumpers on there? I always forget stuff like that.

[madbean]

You could try using a non-polarized cap for the 4u7 or even short the legs temporarily to see if the modulation starts.

[gordo]

I'll give that a shot. I'm not getting the led blinking but the depth control does control its intensity.

[madbean]

I'll give that a shot. I'm not getting the led blinking but the depth control does control its intensity.

Hmm, maybe also try removing the LED.

[gordo]

Arghgh, I tried all the above and no go.  I did "something" to make it swish at one point but by now the board is so jacked up that I think I'll throw in the towel.  I forgot how unforgiving single sided etches are when trying to move/remove parts.

Still, I really like the sound of the echo so I'll give Keefe a holler and see if he'd be interested in doing one.  I don't really mind the process of doing etches but I'm just not geared up for it anymore.

[gordo]

Update.  The Keefe etched board showed today and all is good.  I'll maybe do a post-mortem at some point but for now I'll assume since it was me that built and soldered it with the same parts stash that there was an etch error on my part.  I can deal with that.  The Keefe board is beautiful.

Really nice sounding echo.  I've never really been a fan of the PT chip but this is a really nice sounding echo (which is why I pursued getting it finished) and I assume the newer MB projects go beyond this.  I'd see this doing some duty on my live board and will not be showing it to anyone out of fear I'll never see it again.  Don't see it bumping my Nova delay anytime soon but it has a certain raggedy edge to it that is quite appealing.

Now if I can just box it up with out f**king up the traces...

[gordo]

Got it boxed and after playing it the mod LED isn't working (although the Depth knob alters it's intensity).  There is definite modulation if I peg the Depth control and I think that might be the intent of "Tape" echo.  I'll have to check out the demos of the original.  In the meantime this is a great echo and is a nice bridge between analog (I think I've proven that I'm just not a fan and never will be) and digital (which I love but it's nice to get a more analog sound without all the hassles using the PT chip).  I really don't want to t-shoot this one as I already trashed my own etch and I hate to bugger up Keefe's lovely work.  I'll call this a winner.

I'm looking forward to (and ordered) both of the new MB projects to get a bit of perspective, but this dog will likely get a bit of live work.