BJFE Bone Bender 1 - Verified

[BetterOffShred]

Great Man! I cut a board for this today and then got side tracked with the fuzzbud.. Which is also super amazing.  I built Johnk's version with the tone pot.  

I have some 404B's too.  I'll build it tomorrow

[Mulekicker]

Too funny, my next build is a fuzzbud with a colorsound inductorless wah in one box. I'm hoping I can just use a pot instead of a treadle to get some cocked wah fuzztones. Great minds...

[BetterOffShred]

I got 11 of Tayda 4700uh inductors that I series on a piece of strip for 51ish mH inductor for the fuzz wah ;)  also on my list.  

I'm really trying to have 1-3 of each mark tone bender.  I built the silicon mk2.. and a mk3 .. It's a good pedal to have around.  Need to build an OG mk1 too.  

[Mulekicker]

I haven't been brave enough to build a true mkI yet but I'm gonna give the DAM 673 a go. So far I've made this, a 1.5 with the Super Bee switch, a silicon mkII, a Marshall Supa Fuzz, a Buzzaround, and a 4 knob Park from Rocket's layout. The Park is my fav but I like em all. This is a close 2nd.

[anders]

Me and Sphere80 have tinckered with some of the mods suggested by Björn I've added two more layouts, one with external bias control w. treble cut switch and an all germanium version.

[Sphere80]

I built the version with J113, external bias pot, and switchable treble cut. I used GT404B's.
Like the other Bjorn fuzzes, it cleans up very well and gets great low to high gain tones when the Saturation is backed off.

At max this is a monster of  mushy fuzz and sustain but with it, I get the oscillation others reported. It's quiet when placed after a buffered pedal though. I'll know for sure when I box it up with insulated wires.

Also, earlier in this thread Iggy asked about a PNP conversion.  I don't know the details but there is also a PNP (AC128) commercial version of this.

[moterrac]

I built the middle layout and i'm getting really bad oscillation and noise like the others report with the jfet, I've double checked my vero to the layout and i'm confident it's correct. I'm going to pull the transistors out and try a diffrent layout if I can't get it working, I'm not discounting having dodgy jfets so I need to test them on their own as a buffer or something to see if that's the issue.

[Sphere80]

I built the middle one first and the noise was too much.  I then just built the 1st one as I didn't care about the extrernal bias pot and it's quieter. I don't  know why.  There is still some squeal at max fuzz, but it's better.

How hot are your transistors? You can also raise the value of the ceramic caps. That was recommended as a mod in th original project

[moterrac]

They weren't too hot, around 90 if i remember rightly. I was just looking at the schematic for the bjfe bone bender and theres some weird changes from a normal MkI.  Q2 stage is more similar to a WEM Pep box with a 1M resistor from voltage to base but the collector is 15k, more akin to q3, then we have basically the same setup for q3 with another 1m from voltage to base and another 15k collector resistor. I guess the 1m to base on each of the stages allows for a range of transistors to be used rather than only leaky germs. I honestly have found a standard mk1 easier to build than this if you trim q3 base to ground and dial out the noise. I'll pull my parts off the board and try make a standard one before giving up on this, i'm a sucker for a MKI.

[Sphere80]

Now that I soldered the transistors in as close as I could to the board, most of the noise is gone. I previously had them in sockets and the legs must have been picking things up.

Further reading here, the development blog thread:
https://bjornjuhl.com/forum/viewtopic.php-f=4&t=5456.html