MKI Bender and NGD

[JakeFuzz]

This is my third attempt at getting the MKI right and man does it sound good this time around. I could never get along with the misbiased gated sound of the past ones I had made. After very carefully choosing the transistors though (and waiting for the temperature to be just right  ) you can get a great sounding fuzz. Seriously a 10 degree temperature difference will make this thing sound gated and weak which made choosing transistors from one day to another difficult.

The wiring is messy as it is transplanted from another build. The case is hammertone verde green from Rustoleum. The transistors I settled on were Q1 = GT308V, hfe~55, leakage~very low; Q2 = GET113, hfe~120, leakage~400uA; Q3 = OC80, hfe~80, leakage~650uA. My notes on transistors for this circuit are as follows:

Q1: Low leakage provided much less gating in the circuit. Gain is not critical as long as it is above about 40.
Q2: This is the one to play with. Leakage should be moderately high and gain should be as high as possible. I tried to use low leakage in this position but it would never bias properly. I almost ended up using an OC305 with hfe~200 and leakage~600uA but it sounded too bright. This one has a large effect on the frequency response and the GET darkened and smoothed things up nicely. AC125's were a close third in this position.
Q3: Also super finicky. I tried many in this position. It seems to only like high leakage transistors. The OC80 and several OC79's sound very good. Gain should be fairly high or sustain starts to lack. AC125's and Japanese 2SB's were close but the OC80 definitely had something special.

Overall this circuit is just crazy sensitive to what you put into it. I probably tried 20+ different transistors in Q2 and Q3. I also put 150pF smoothing caps from collector to base on the last two transistors to remove this funky oscillation at both low and high frequencies. When it gets colder in the room the circuit starts to gate a little bit. It is probably a good idea to test with the guitar you intend to play with the most. I found it is fairly sensitive to the output of your pickups. With buckers I get a lot of that slamming into a wall sound. I would say it is worth it though if you have a stash of transistors to play with. It just sounds so damn gnarly and raw.
[soundcloud]https://soundcloud.com/jakefuzz/ziggy-fuzz[/soundcloud]




And I have been working on a guitar I bought a few months ago and finally finished it and used it for this demo! This is the very rare color seafoam green OLP MM1. I got it for about $100 and the neck was beat to hell. I re-profiled and refinished what was a really chunky weird feeling neck. I also leveled and crowned the frets and put in a brass trem block. The neck pocket looked like someone gouged it out with a chisel (apparently many OLP users have reported similar pocket finish quality) so I bedded it in epoxy. Sounds, looks and plays like a teenage dream   (Oh Katy!)

[nzCdog]

Man oh man... great tone and playing paul... congrats on the new axe and build, both look lovely

[Haberdasher]

whew, that sounded great!

[JakeFuzz]

Thanks guys! I am having a hard time not playing Ziggy Stardust... I think my roommate is about to kill me 

[slimtriggers]

That really does sound excellent.  Nice work!