I almost didn't post this one, as it's really really close to the Hot Silicon Fuzz - but I was curious after seeing the post on FSB and I haven't done a regular / still in production circuit for a while.
Josh Scott says that sonically it's an approximation of his favourite seventies MKIII Tone Bender, it's roughly a silicon MKII up front, with a transistor acting as a buffer to separate it from the tone control. The JHS switch changes some resistance to ground on the Attack pot and adds an additional path around the tone control to the volume pot. Anyways, check out the FSB post for the schematic, and you can see for yourself.
JHS BENDER, LONDON 1973 - VERO LAYOUT
It's worth considering how the 4k7 and 1k8 resistors attached to the fuzz pot & switch are wired to ground. The one above has them connected to pin 2 of the fuzz pot, with pin 1 not connected (which is according to the schematic traced).
It has been suggested that it would be better to have these on pin 1 - and there's certainly some merit to this idea. I've not built this - so I guess give it a try and see what works for you.
15 comments:
I saw the post of FSB and serendipitously found your blog. I love the Mictester and the BA Scarab so I was interested in trying this recipe too. It sounds like the circuits that inspired it. Couple corrections though. Q2 should be a 2n2222a, Tone 2 connects to switch lug 3 and the 100nf connected to the collector of Q4 should connect instead to the emitter of Q4. Curiosity satisfied. Thanks for the layout man.
Thanks - I messed that one up pretty well. Will repost with corrections.
Not really. Your skills are beyond mine. Appreciate your sharing. Thanks again.
Where does the 2.2M resistor go to (row 6)? Does it just terminate to nothing?
Should be on the input to ground.
Layout updated - just a resistor to ground from the input.
Thanks for demistifying this one, so not based on a MK3 at all!
It's still a good sounding fuzz, and if it's giving Josh MKIII vibes, then who am I to judge.
I've built the basic audio scarab, so i guess the only benefit of building this is to have fewer knobs. Actually,that seems reason enough. Great site by the way, thank you. BTW i couldn't find the FSB post, any chance of sending me the link? Cheers
https://www.freestompboxes.org/viewtopic.php?f=7&t=32807&p=296320#p296320
that 100nF cap at the top of column 8 - does that span rows 1 to 2 or 1 to 3? It looks like it is right between them. Thanks
Never mind - figured it out 😁
Cool - yep, 1 & 2. Just some extra filtering on the power supply.
Hi, tank you for the layout. What should be the hfe of each transistor?
Hello - have a look at the datasheets. BC108C is on the higher side, 2N2222A is low.
Post a Comment