tagboard earthquaker hummingbird tremelo

[peterg]

I built the above mentioned pedal and don't hear the effect. The volume pot works but nothing else. The changes I made were grounding the mode switch to the outjack not to the baord. I couldn't find any 2n2646 trans so am using a 2n6027. I've tried all pin variations. Any suggestions why there is no effect?

[midwayfair]

Try this:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[Chugs]

The 2N6027 is not a straight substitute for the 2n2646. It will not work without modifications to the circuit.

There are suggestions for modifications to make a 2N6027 work with the circuit at FSB.

[abenfVA]

You don't happen to have a schematic, do you?

[peterg]

Thanks Guys

Chugs - what is FSB? I'll look it up. Hopefully I can salvage the board.

AbenfVA - I couldn't find a scheme just the tagboard vero layout. I found a Vox Repeater scheme which the hummingbird is based on but there appear to be extensive mods.

[moosapotamus]

My SKIPPY pedal is a modified VRP, but you can find details about replacing the 2N2646 with a 2N6027 in the documentation...

http://www.diystompboxes.com/smfforum/index.php?topic=102557.0

~ Charlie

[peterg]

Thanks Charlie

I found the schematic and am wworking withh it. I wish I had found it earlier! It looks like a great circuit.

[peterg]

Charlie

I added the R12 as per your mod for the 2n6027 but still am not getting oscillation. Does R9's value make thaat much differnce? Currently I have a 470r resistor.

Thanks

[moosapotamus]

Yes, the value of R9 will make a difference. Try combining a couple of resistors in series to add up to 2K if you can. Then tweak the trim pot to dial in the oscillation at both extremes of the speed pot.

~ Charlie

[Electron Tornado]

Was reading this thread and ran across something that might be of interest:  http://www.premierguitar.com/Magazine/Issue/Daily/News/Magnetic_Effects_Announces_Electrochop.aspx

[peterg]

Thanks Charlie. I'll give it a try.

Electron T - thanks for the info on the eletrochop.

[peterg]

Charlie - R9 was the issue. Sounds great now. Thanks for your help.

[moosapotamus]