Toan-a-Saurus

[BurntFingers]

Weekend leftover parts project complete. The enclosure is from 2011 and one of Tayda's older style ones that are shorter and narrower than what they currently stock so I dicked up the drilling and left a vent at the top. Handy actually as there's too much toan in here anyway.



It's sort of an Electra distortion but built with whatever was in the drawer so not exactly to spec. Has a BC549 in there, a big muff tone control, I think a 220R coming off the emitter (as oppose 330R). I used the layout for the Woodrow from Tagboard effects.

It's a fun pedal. Definitely low gain (probably because of the pot value for the gain, I didn't have a 1k so had to use a 5k) and unity volume is about 80% of the dial.



I'm using it as a boost on a slightly dirty channel, or as a bit of grit on the clean channel. It definitely suits laid back, chilled bluesy crap with some warm reverb in the background. It's actually quite nice to not have a pedal where unity is 3/10 of the volume pot because it generally means you don't get the most out of it unless you can crank both the drive and the gain (looking at you, Hot Cake) which messes up any balance with the clean channel.

Fun stuff. Got a 1w resistor coming off the LED for maximum mojo tone.



Excuse the rat's nest wiring. Vero is a whole lot of fun.

 

[BurntFingers]

Actually I think the drive pot has had it. There's no change in the amount of gain except for the final 10% of the sweep so I'll change it out tomorrow for a new one. The one in there is from 2009.

 

[Chuck D. Bones]

Maybe DRIVE has the wrong taper. Should be C, right? Go Vero!!!

I like the distressed stomp switch.

 

[BurntFingers]

Maybe DRIVE has the wrong taper. Should be C, right? Go Vero!!!

I like the distressed stomp switch.

You probably know better than me on that front. I think it's a b taper since that's generally what I have... Although I might have a c5k from a furloughed sho build.

The gain pot comes off the emitter of the transistor in this case. The mod calls for a 1k which I didn't have. Would a 5k result in less gain being available?

Cheers for the advice.

 

[phi1]

Max gain in this setup will be when the pot lugs 2-3 are zero ohms. Both pots can achieve this max gain equally. The 5k will just have a lot of useless sweep like you noticed. From 1k to 5k (or the first 80% of the sweep), there won’t be much noticeable change. It’s because in this circuit it’s acting in parallel with the 220R to set the gain. So 1kB would work better. 1kC might be worth trying too.

 

[Barry]

Love the enclosure, great looking build!

 

[BurntFingers]

Max gain in this setup will be when the pot lugs 2-3 are zero ohms. Both pots can achieve this max gain equally. The 5k will just have a lot of useless sweep like you noticed. From 1k to 5k (or the first 80% of the sweep), there won’t be much noticeable change. It’s because in this circuit it’s acting in parallel with the 220R to set the gain. So 1kB would work better. 1kC might be worth trying too.

That's great information, thanks for taking the time to chime in.

It got me thinking though. If the 220r is setting the gain as it is now, lowering that would result in more gain right? I think the lowest value I have here is a 10 ohm and I'd like to squeeze some more juice out of this box.

 

[phi1]

I believe it wouldn’t help get more gain in this case, because with your gain knob maxed, the AC signal already sees 0ohms through the capacitor.

Ge or Schottky diodes would clip harder, so that might be worth experimenting to get the sound of more gain.

 

[BurntFingers]

I believe it wouldn’t help get more gain in this case, because with your gain knob maxed, the AC signal already sees 0ohms through the capacitor.

Ge or Schottky diodes would clip harder, so that might be worth experimenting to get the sound of more gain.

Aye that was a consideration, but I don't have any volume to lose which I think extra clipping would deliver.

I'm curious about popping a 10k pot from emitter to ground to function as a gain control in any future iterations. Or do as Beavis Audio suggested with their Trostsky drive:

Rather than a 47k going into the Collector, he put in a 50k pot. If I'm reading that right it's a bias control for the transistor there which I guess is sort of the same thing as a 10k pot on the other end.

Next plan is to stick with the BMP tone stack but put a gain recovery stage afterward (LBP1 probably) to give a boost in overall level.

There's a lot of scope in such a simple circuit.