Auto Swell?

[Arn C.]

Is there such a thing as auto swell?   Like what you can do with your volume pedal,  bringing the sound from no volume to higher volume and back again or vice versa.

Not sure if I am getting my thoughts across!

Peace!
Arn C.

[smoguzbenjamin]

You mean the slow gear Someone re-did that schem without the FET switching but at least that's a starting point for you I wish I could find the schematic... I can't find it anywhere!

[Marcos - Munky]

You can do this with a LDR between the in and out jacks and a LED drived by envelope detector. I think the Boss Slow Gear does the auto swell too.

[strungout]

The one with the FETs is at GGG, filters.

This here http://members.shaw.ca/roma/ is the only one I found that doesn't use FETs, and is much more simple. I haven't tried it yet tho. Hope it helps.

[Rodgre]

Check out Paia's Gator kit.

It's a noise gate which has a very slow attack control which will do the Slow Gear thing. It also has an external input so you can do gated/triggered tremolo.

Roger

[Arn C.]

Thank you everyone for your help!!!!

Peace!
Arn C.

[Mark Hammer]

RG Keen's LERA circuit is intended to accelerate and deccelerate the modulation speed for Leslie simulation but it does so by varying the resistance of a photocell.  Absolutely no reason why that circuit couldn't be adapted to provide a preset volume to be faded up to and down to.

Actually, RG sent me a copy of an old Electronics and Music-Maker project article on a device actually *called* and "Auto-Swell" which does exactly what you describe, only with an FET as the control element.  The nice thing about the LERA is that LDRs are kind of bulletproof when it comes to signal levels, so you could stick that thing after a trio of Blackfire pedals in series, each running off a 30v supply, and it would still provide reasonably distortion-free fade-in/out.  The same could not be said of an FET-based swell function, which would need to either be stuck at the start of a signal chain, or have its signal conditioned in some manner to avoid distortion in the FET.

[Arn C.]

Thanks for your replies!

Maybe I will give the Lera a shot!

Peace!
Arn C.

[bwanasonic]

If you feel really ambitious, the EH Micro-Synth does *auto-swell* effects. One of the Prescription Electronics pedals also does this (experience?), but I have never tried one. Never underestimate the power of either the volume knob of your guitar or a volume pedal though. And my favorite, genuine backwards guitar tracks.

Kerry M

[Rodgre]

If you feel really ambitious, the EH Micro-Synth does *auto-swell* effects. One of the Prescription Electronics pedals also does this (experience?),

The swell circuit in an Experience does not really do a volume swell, per se.

Picture it like this: You have two pedals and a patch cord between them. The first one is a Foxx Tone Machine, and the second one is a crappy little fuzz box. If you run the Tone Machine into this crappy fuzz, you hit the input of the second fuzz so hard that the sound collapses for a second and then swells back up. It's a very cool sound, but it's not like an autovolume swell. It's sort of analogous to someone wanting to use an octavia to make their guitar sound like a 12-string. Sure, it adds an octave up...but not like you think....

Roger

[KarbonHed]

Check this out...

An old Electronics And Music maker project from a decade or more ago.



A zipfile of the full article is here (640k).

[Mark Hammer]

That's the very article I mentioned.  Thanks.

[Arn C.]

Man, this is what I was looking for!  Thanks for the find and the post!
Although, I will still make the Lera, maybe try to adapt it into my phase 45.
Thanks again!
Arn C.

[KarbonHed]

That's the very article I mentioned.  Thanks.

:shock:  I somehow managed to read every post in the thread except your's and it's the one that mentions the article I scanned  :oops:

Man, this is what I was looking for!  Thanks for the find and the post!
Although, I will still make the Lera, maybe try to adapt it into my phase 45.
Thanks again!
Arn C.

Glad I could help.

[RickL]

I just finished building the Auto Swell posted here and it works pretty good. I used the published layout, built 4ms cbcb method on Formica and it fired up right from the start.

I used 2N3904s for the BJTs and an MPF102 for the FET. I also added a dpdt to completely bypass the whole effect.  I wanted a little more volume so I added a 47k resistor in series with R5 (220k) and with the Range control in the fully CW position there was no volume at all so I added a 10k resistor in series with the pot so the volume never went below unity.

The speed control has a very wide range. It seems to me to be most useful in the top quarter of the pot's rotation (smallest values) so I may change it to a 250k pot.

It's definately an interesting variation on the Slow Gear/Gator theme and an easy build with common parts. Thanks KarbonHed for posting it.

[KarbonHed]

I just finished building the Auto Swell posted here and it works pretty good. I used the published layout, built 4ms cbcb method on Formica and it fired up right from the start.

I used 2N3904s for the BJTs and an MPF102 for the FET. I also added a dpdt to completely bypass the whole effect.  I wanted a little more volume so I added a 47k resistor in series with R5 (220k) and with the Range control in the fully CW position there was no volume at all so I added a 10k resistor in series with the pot so the volume never went below unity.

The speed control has a very wide range. It seems to me to be most useful in the top quarter of the pot's rotation (smallest values) so I may change it to a 250k pot.

It's definately an interesting variation on the Slow Gear/Gator theme and an easy build with common parts. Thanks KarbonHed for posting it.

Glad it worked for you, and that it was "do-able" with easily purchased components and that it was easily tweakable to suit what you needed from it.