Fade In, Fade Out Pedal?

[KerryF]

So I got a question from someone about making a pedal to press to Fade In and Fade Out I guess when in a gig or something.  Well some people suggested just using the volume knob or a volume swell pedal.  I thought that there may be some way to do this using a type of Tremolo circuit.  Its just an idea if anyone wanted to design a pedal but couldnt think of what to make.  I was thinking something about using a Tremolo pedal, setting the speed to the lowest, and engaging it to fade out and then disengaging it when it reaches the lowest point.

Anyone have any ideas of how this is achieved?  Anyone feel like trying to build something like this.  I have no idea how tremolos are designed yet so I thought I would put it out there for all of you to think about.  Tell me what you think  .

[tiges_ tendres]

the boss slow gear does the kind of stuff you want.  There are a couple of projects around for that.

Also, guyatone makes a mini pedal that does the same thing too.

[KerryF]

Oh ok.  It wasnt my idea, just putting it out there as an idea.  Because someone else asked me how it would be done and all.

[R.G.]

The simplest way is probably to use an LED/LDR as the controller and then drive the LED with a current which increases/decreases.

Another way is with an OTA variable gain chip and control the current into that thing's control node. Robert Penfold had a circuit something like this published in Electronics and Music Maker in the UK about 10 years ago, maybe more.

It's not hard, it just takes the time to sit down and do the math.

[KerryF]

The simplest way is probably to use an LED/LDR as the controller and then drive the LED with a current which increases/decreases.

Oh yea, that probably would work!  I never thought of it that way, but now I understand.   .  Thanks.

[The Tone God]

You can always try something like R.G.s LERA or another cap charge/discharge circuit and just control the optocoupler with that. I think that is really simple.

Andrew

[Torchy]

Find a BABANI book by Penfold called "Modern Op-Amp Circuits", its called an Auto Swell Pedal.
Also have a look at the Paia Ducker circuit and use a control voltage to duck the input.

[Steve Newton]

the Autoswell schem is in the archives at http://experimentalistsanonymous.com/ somewhere.

[KerryF]

Ok so a guy came up with two schematics for something like this.  I decided to show you all to see what you think of them...
http://www.putfile.com/pic.php?img=3324220
http://www.putfile.com/pic.php?img=3326201

[Torchy]

Thats the one, its in "Guitar Synth & Misc", 3 scanned pages.

Thanks

[Steve Newton]

Arn C. had a very favourable build report when that schem was first scanned and posted here...
http://www.diystompboxes.com/smfforum/index.php?topic=20418.0

[KerryF]

Thats the one, its in "Guitar Synth & Misc", 3 scanned pages.

Thanks

Oh seriously...  I will make sure he knows that everyone knows he didnt create it  .