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Toecutter and Transistor Pinout

Started by angrykoko, September 03, 2014, 11:25:03 PM

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angrykoko

Hey Guys,

I have 2 questions related to the Toecutter circuit and it's transistors.
For reference: http://apocalypseaudio.blogspot.com/2010/02/toecutter-v1-revc-pcb-layout.html

Edit:  forget question 1, I must be just tired.  My head didn't flip from bottom to top view correctly.

First, if anyone can read the image below... can you please tell me the pinout.
I've tried google translate and Bevis Audio's reference but, I think I'd feel better just asking because I seem to only get it to work if they are in backwards from my 2 references.
It's supposed to be a GT313A transistor, this came with them.



Next Question.
Has anyone here built the Toecutter circuit?

Mine works but I'm not sure if it's correct, I absolutely cannot have the guitar's volume maxed (single coil or humbuckers).  If I do then the circuit (or transistors) seem to overload and shut off for about a 1/2 second when you hit the strings.   Is this behavior correct?  I've tried different GT313's and even built a second pcb but same results (which is also why I'm wondering if I have the pinout wrong).
Controls work as described by others and as long as I don't dime the guitar's volume it does sound very doom and heavy.

Thanks!
Koko
The early bird may get the worm, but the second mouse gets the cheese in the trap.

twin1965

I haven't built the Toecutter but I can help with the pinout. From the top: Base, Collector and Emitter. I can't read Cyrillic but I think I'm right.

I believe the transistor case is grounded. So make sure that they're not touching anything.

Sent from my GT-I9100 using Tapatalk 2


davent

I'll second that pinout, from the top b/k/e,  same as the GT308 are that i have.  Case is connected to 'k', with the GT308's in hand is clearly visible. Black dot on case to indicate the emitter. I've a couple multimeters with hfe and for unknowns i just pop them in the various pinout arrangenments until i get a reading that makes sense.

And not familiar with the Toecutter.
"If you always do what you always did- you always get what you always got." - Unknown

If my photos are missing again... they're hosted by photobucket... and as of 06/2017 being held hostage... to be continued?

midwayfair

Top to bottom: Basa (base), kollektor (collector), emmiter (emiter); to the right is korpus ("body"), the actual outside of the case, which can be grounded in some instances.

The number columns on the right of the chart are "ne meneye" (no lower) and "ne boleye" (no larger) -- the gain is the last row (coefficient forward something of small signal, but it also says hfe :P).

Above the chart is the maximum electrical parameters, followed by the temperature.

One thing the datasheet does not tell you is that there is an internal resistor in the transistor. I think it's collector to emitter.

angrykoko

Thanks Guys!

It took my wife to snap me out of not seeing the pinout correctly. I'm sure there is some mental jargon to describe it but I just kept seeing it wrong when would try to flip from looking at the bottom and inserting into the socket.  Weird.. and days of it happening.

Also having the base not in the center really messed with me when I was looking at the pcb layout I kept thinking.."this is all messed up, why is he running the input to the collector".  I think I've been at work too long lately  ;D

I'm going to have to do a demo of this one, if your into doom playing this will definitely make you feel sad and depressed, it's really sludge in a box.

Thanks again!
The early bird may get the worm, but the second mouse gets the cheese in the trap.

blearyeyes

Pick up one of these little gizmos and it will help a lot... Tells you what it is that's attached, what pins are connected to which input etc. Hfe, leakage, Vf etc. Even lets you know if you have two diodes hooked up. Gives you ESR on caps... There's a couple of versions..

http://www.ebay.com/itm/Transistor-Diode-Tester-Capacitor-ESR-Inductance-Inductor-Resistor-Meter-/281235252022?pt=LH_DefaultDomain_0&hash=item417aed6336