Electra Distortion Volume & Gain Pot Q & A ?

[HOTTUBES]

I have built the fallowing basic circuit , but i need to know where & how to wire in a Volume pot & Gain Control ?








What Value & type of pot should be used for the gain control ?



Thanks a Million !

[dan5150]

The Electra was one of the first things I ever built. When I dug out my old schematic, it shows a 100k pot that would go between the Out and the G (ground) on your diagram.

It took me a few moments in looking at your diagram to realize that the transitor isn't physically shown. Although it's connection points are. FWIW - I used a 2N3904 in mine.

-Dan-

[HOTTUBES]

Thanks Dan !!

So , the Volume pot is taken care of ...

Do you know where to put the Gain pot etc ?

[mistahead]

I don't think it has a gain pot by "standard" - when I knocked this one up I did it from:
http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album17/album06/ELECTRA_DISTORTION_001.gif.html

Someone with more experience may be able to offer how to add a gain pot but I have found it to be acceptable without - that is not ridiculous, and just dial back the guitar a little if it is still too strong...

[HOTTUBES]

Does the Volume act like an old Master on a Vintage Marshall etc ??
The louder you run it , the more gain on tap ?

Cause then a seperate gain may not be needed afterall  !



Thanks

[mistahead]

I'm no master of circuits but using some logic and looking back over the vero I can say maybe but probably not... I'm only commenting in the hope that someone either confirms or dispells and explains what I THINK is going on...

The pot between the ground and the output proper is just acting as a voltage divider at that point, the amount of influence it will have back at C1 on the vero I linked earlier will not be significant enough to adjust the gain in the "loop" (yes I'm a newb trying to work out the logic). I hope someone with good knowledge jumps in here...

To be honest my experience is that this is a fairly "balanced" sounding circuit and not a balls-to-the-wall ear bleeding distortion anyway - I would rate it in the midline along with some tamer OD's and maybe even a 250 for the amount (though not necessarily sound) of distortion it produces, winding back the gain on it would result in some nice crunchy break up but it is definately not a super-metal-squealy-doom box or the dirty channels on a mesa lol.

[CynicalMan]

No, it just controls the volume. The way I like to set up the gain control is to use a 500k log pot, with lugs 2 and 3 tied together, connected in series with the input. It works backwards, so it's more of a 'clean' control. If you don't want that, use a reverse log pot and tie lugs 1 and 2 together.

Edit: Here's the schematic:


The volume pot doesn't affect the gain because its load on the transistor stage is always 100k, no matter where the wiper is. If the input impedance of the next stage is very low, then the load on the circuit would change depending on the volume setting, but most of the time it doesn't matter.

[ashcat_lt]

I think the 680R to ground sets the overall gain of the circuit.  Replacing that with a variable resistor, possibly bypassed by a cap, would allow variable gain.  I'm not the one to ask about values there, though.

[CynicalMan]

To do that, you'd use a 1k pot with the outer lugs connected as a resistor and with a cap from the wiper to the ground, like in a Fuzz Face. However, that only increases the gain a bit. The pot in series with the input reduces the gain, with a very large range. It's more versatile IMO. Of course, the way to get the best of both worlds is to put in a capacitor in parallel with the 680 ohm resistor and then use the pot in series with the input. That way you can get higher or lower gain than the stock electra. Check this out:
http://sites.google.com/site/distorque/home/projects/modded-electra-distortion

[Electron Tornado]

If you're looking for a way to control how much your signal gets clipped, take a look at this page:

http://www.muzique.com/lab/warp.htm

[HOTTUBES]

Yeah , thats a great read , but you guys have to remember i'm a noob at this stuff , i'm doing my best to learn
but there's alot of ground to cover to catch up with alot of you guys .  there's alot of smart cats
around here ....

Maybe i will just go with the VOL for now ......


Thanks for everyones input on this topic !
special Thanks to Cynical man !!!

HT

[tubelectron]

Hi HOTTUBES,

Here's what I have done from the Electra : le Crunch à l'Huile, in a small tuna tinbox. As you can see there is the 2 controls as usually found on an overdrive, but thanks to the 1N4148 instead of 1N34A, consider it as a "ditry-able transparent" booster only. The 1N34A gave more drive but less output level, and not enough compared to the dry level.



A+!

[Electron Tornado]

Yeah , thats a great read , but you guys have to remember i'm a noob at this stuff , i'm doing my best to learn
but there's alot of ground to cover to catch up with alot of you guys . 

It's a journey, yes, but not a race.

I often get to put my noob hat on, and it makes the journey more interesting.

[HOTTUBES]

Hi HOTTUBES,

Here's what I have done from the Electra : le Crunch à l'Huile, in a small tuna tinbox. As you can see there is the 2 controls as usually found on an overdrive, but thanks to the 1N4148 instead of 1N34A, consider it as a "ditry-able transparent" booster only. The 1N34A gave more drive but less output level, and not enough compared to the dry level.



A+!

Thank you for posting this pic !! 

[HOTTUBES]

Yeah , thats a great read , but you guys have to remember i'm a noob at this stuff , i'm doing my best to learn
but there's alot of ground to cover to catch up with alot of you guys . 

It's a journey, yes, but not a race.

I often get to put my noob hat on, and it makes the journey more interesting.

Well said ........