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Projects => Build Reports => Topic started by: Matt on April 08, 2015, 04:56:18 AM

Title: Tone Bender MKII
Post by: Matt on April 08, 2015, 04:56:18 AM
I've been on a bit of a fuzz kick lately. Basically, i made an ill advised eBay purchase of 100 gt308 Russian ge's. So I decided to put a few to use.

i learned a lot on this build. First of all, as many of you probably already knew, Tonebenders like Q1 to have some leakage. Couldn't get it to make a sound at first with the gt308. I found a thread where mac from DIYstompboxes recommended using a resistor from collector to base to simulate leakage. Bam! It was alive. A lot of different tones can be had by playing with the value of this resistor. In the end, I settled on a 1M5.

I spent the last three weeks with this thing on the breadboard trying different collector resistances. I would make an adjustment then come back a a day later to listen again.  I have to say that the effort payed off. This is the best sounding fuzz I've ever built. I
also ended up using bias pot for Q2. I found a thread where Jon had mentioned that this method is better than the more common bias pot on Q3.

Anyway, enough rambling, here it is. I've included a schematic for anyone who is interested. By the way, the HFEs that I used are 71, 74 and 79
Title: Re: Tone Bender MKII
Post by: jalmonsalmon on April 27, 2015, 09:59:48 PM
 Nice one!
I love tonebender mk II's
I have a few of thos gt308's as well and I may have to try some of those on the ol breadboard!

Title: Re: Tone Bender MKII
Post by: cooder on April 28, 2015, 02:38:30 AM
Nice classic one there, great build!
Title: Re: Tone Bender MKII
Post by: Matt on April 28, 2015, 03:07:40 PM
Quote from: jalmonsalmon on April 27, 2015, 09:59:48 PM
Nice one!
I love tonebender mk II's
I have a few of thos gt308's as well and I may have to try some of those on the ol breadboard!


Quote from: cooder on April 28, 2015, 02:38:30 AM
Nice classic one there, great build!
Thanks! 
That's cool, let me know what you think. It'll be nice to have someone else's opinion.
Title: Re: Tone Bender MKII
Post by: lincolnic on April 28, 2015, 05:56:42 PM
Thanks for including your schematic for the Q2 bias pot -- I have a half-finished Tonebender build where I initially wired the bias pot for Q3, and I didn't totally love the result. I'll redo it for Q2 and hopefully be happy enough to box it up!