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new blend idea?

Started by vendettav, February 27, 2011, 01:20:55 PM

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vendettav

ok guys so i was thinking about putting two effects into one enclosure... like a fuzz and may be the octup from escopedo... or a overdrive or something idk yet... i was thinking to have a SPDT switch in the end to pick which circuit is being fed to output/master vol. so the new idea is. what if i put a dual ganged pot.lug 3 is the output from the 1st circuit lug 2 is to volume lug 1 ground then second gang lug 3 is the output of the 2nd circuit lug 2 is the ground and lug 1 is to vol. it'll go from FX 1 to FX1/FX2 to FX2... will this work?? and what pot shall i need??? 100k?
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R.G.

That will work. It was one common way of doing crossfades back in the day when opamps were not available or expensive. As a purely passive way to do a blend, it has some drawbacks, but then it's cheap and easy, depending on how easily you can get dual gang pots.

However, if you can afford one opamp and some resistors, you can do a panner with a single pot, and have it not suffer the drawbacks that a single-pot blend does. See "Panning for Fun" at Geofex.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Gurner

Perhaps I'm off whack here...but if you're wanting to fade between two  existing effects, the signals will be  being fed from a low impedance source - why not just put one 10k linear pot...one outer lug to one circuit's output, the other outer lug to the other circuit's output....the wiper is your output.

R.G.

Quote from: Gurner on February 27, 2011, 03:03:33 PM
Perhaps I'm off whack here...but if you're wanting to fade between two  existing effects, the signals will be  being fed from a low impedance source - why not just put one 10k linear pot...one outer lug to one circuit's output, the other outer lug to the other circuit's output....the wiper is your output.
It works, kind of. The attenuation from one side to the other is not all that good. That's the way all the quick and dirty blend/pan things are done. For it to work well, the two pedals have to have an output impedance quite a bit lower than 10k themselves. That's not necessarily always satisfied. If this is the case, then the blend amount varies with the setting of the output volume pots on the effect, and changes with the volume setting as well as the blend.

You're not out of whack - but the person with the need to blend has to decide what degree of imperfection is too much.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.