Tonebender Mk II Transistor Hfe question

Started by Krinor, July 24, 2007, 05:24:06 PM

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Krinor

Hi guys!

I just got my matched transistors from Small Bear today and I wondered if someone could tell me where to place them ?
I'm building my Tonebender on the GGG pcb. My transistors have Hfe values: 85, 93 and 165. Question is which ones goes where. Do I add up like this: Q1=85, Q2=93, Q3=165, or vice versa ? 

Cheers,

Krinor

jlullo

yes what you have looks right according to Fuzzcentral. 

Q1 and Q2 are interchangeable, so you can try both in each position!

Krinor

Oops.
Seems like I forgot to say Thank you.  :icon_rolleyes:
Thank you.   :icon_wink:

My Tonebender turned out very nice. But I wonder if there may be some mistakes in the GGG layout file ? This is my first positive ground build and I found it rather bewildering at first. My problem is that the led isn't working. I've wired it exactely like the GGG layout, but nothing happens. I feel like a complete idiot now.  :icon_redface: The only way I can get it to work is by wiring it to the input jack thus making it come on when the jack is inserted. I'm using a 2.2 V, 30mA green led with a 4k7 resistor (I don't like bright leds). Anyone care to point me towards a former thread or a link on this issue ?

jlullo

you're welcome!  how do you have the LED wired when it's wired to the switch?

it should be the negative lead going to the -9v power supply with a resistor in between, and the positive lead going to the switch

Krinor

Once again: Thank you!  :icon_biggrin:
It's working now.
There IS a mistake on the GGG layout. In that file the negative lead is connected via a resistor to ground, and the positive lead is connected to the switch.

jlullo

you're welcome!  i'm glad i could help

it would be wired that way if it was a negative ground circuit, but since you have it PNP, the negative lead needs to be fed the -9v

Krinor

Of course. I see that now.  :icon_wink:
I hope I'll be able to assist you in return some time.

jlullo