GGG Leslie Simulator

[magodellepercussioni]

Hi everybody, I'm quite a newbie in the diystompbox world, but I developed a recent interest for analog circuitry, so I'd like to try to build my first pedal.

I've chosen the leslie simulator project from General Guitar Gadgeds,
http://www.generalguitargadgets.com/index.php?option=content&task=view&id=122&Itemid=140
and I have some question for you.

1) I live in Italy, then I have 220VAC current coming out from the wall. Moreover, I'd like to avoid playing directly with 220V for the moment, so I thought I could use an AC/DC wall-wart followed by a voltage regulator. The question is, can you gather from the schematics
http://www.generalguitargadgets.com/diagrams/les_sim2.jpg
what is the correct voltage to be applied? Do I have to remove capacitor C1 or is better to keep it to reduce hum?

2) The circuit can be bypassed with the pair lamp/photoresistor. I have a small photoresistor and LED (around 5mm diameter, don't know exactly ohm ranges) which I used for another project, do you think they can substitute the two components from the schematics? Or is there a simpler but still efficient way to connect an on/off footswitch for bypass?

Thansk a lot in advance for help!

cesco

[axg20202]

Hi everybody, I'm quite a newbie in the diystompbox world, but I developed a recent interest for analog circuitry, so I'd like to try to build my first pedal.

I've chosen the leslie simulator project from General Guitar Gadgeds,
http://www.generalguitargadgets.com/index.php?option=content&task=view&id=122&Itemid=140
and I have some question for you.

1) I live in Italy, then I have 220VAC current coming out from the wall. Moreover, I'd like to avoid playing directly with 220V for the moment, so I thought I could use an AC/DC wall-wart followed by a voltage regulator. The question is, can you gather from the schematics
http://www.generalguitargadgets.com/diagrams/les_sim2.jpg
what is the correct voltage to be applied? Do I have to remove capacitor C1 or is better to keep it to reduce hum?

[/quote]

In the parts list the transformer is listed as 12.6 V. 300ma. In other words, that's your DC voltage (a 12v supply will be fine I'm sure) and the power supply should be rated up to at least 300mA or more.

IMO, which you can freely ignore, I would not make this your first build. Start with something simpler like a distortion box, booster etc. You will find simpler builds more rewarding as success is more likely, and it will give you the experience and confidence to tackle more complicated builds. There's loads to choose from at GGG and tonepad, for example, where the hard work of working out how it all works has been done for you. You don't want to start with a build like this where there a issues/workarounds that you need to decipher before you've got your feet wet building something simpler.

[magodellepercussioni]

ok!
I'll follow your advice.

Thanks!

[axg20202]

No worries man. Assuming you're building effects for guitar, I can recommend the Big Muff Pi (the layout at tonepad is very good - the 'triangle' version is great).  Or, if you want to start on something even simpler, something like a MXR Distortion + clone is a very simple build indeed. This will get you started making your own PCBs and is ripe for experimentation with different clipping diodes etc etc. You can learn a lot from these simple circuits, including powering effects, how to wire pots, connectors and switches, how to box them up  etc etc. Better to learn all this stuff without having to debug a large circuit in the process.

[slideman82]

Has anyone build it? I want to know how does it sound...

[Mark Hammer]

It will sound a bit like the Phozer over at runoffgroove.com.  The circuit shown eventually turned into the "Synthespin", a PAiA project/kit that was essentially a swept bandpass filter whose sweep could be custom tailored and even voltage-controlled.  Ultimately, though, it is "merely" a bandpass filter, whose emulation of a fast Leslie might be as acceptable as some phasers, but whose slow Leslie emulation will leave much to be desired.  Doesn't mean it isn't a musically valid effect, but if you thought you were going to get lush swirly sounds, best look elsewhere.

[DougH]

I breadboarded that leslie sim a few years ago and it can run off of 9v. You have to rebias the transistor but it will work. You could build it to run off of a 9v battery or wall-wart like other current pedals. I agree with Mark, though- build the Phozer instead. It's a ready-to-build 9v project that does the same thing. FWIW, it's not what you typically think of as a "leslie" sound. It is more of an automatic wah-wah. Slower speeds are somewhat lush while the faster speed is a bubbly psychedelic sound. I think it is kind of cool in a way, in the sense that it's not a phaser/flanger/chorus effect, which are fairly common these days. It is more primitive in some ways, but also produces a sound that is kind of unique compared to other time-based effects.

(edit: Actually it looks like ROG came up with a new Phozer circuit that sounds more like a phaser. The original was more of a "wah" sound.)