Not strictly my layout, as this is a copy of the original Sola Sound Tone Bender MKII board.
This is a little different to most MKII schematics, as it has a 10k resistor from base to ground on Q1, and a 47k on the collector of Q2. I've read that this is best for leaky OC75 transistors (which I have a few of). The 100k bias resistors were mainly used for OC81s.
SOLA SOUND TONE BENDER MKII PROFESSIONAL - VERO LAYOUT
If I were to built this with OC81D-like HFE, what gain would I be looking for? I read somewhere that building an MKII with the combination 50-55/55-60/70-90 is possible, right?
ReplyDeleteBtw, where do you get these beautiful vintages veros? I can't find them here in Germany.
Hello.
DeleteI buy my vero from RS in Australia. Nearest I could find for you is RS in the UK. They only have one board with the vintage size pitch (3.8mm)
https://uk.rs-online.com/web/p/stripboards/0433832
Another online store in the USA sells pre-cut boards. https://www.tubesandmore.com/products/pcb-vintage-style-circuit-board-mkii-fuzz
I’ve never made a MKII using OC81 transistors, so I can’t say for sure. Sorry if I have asked you this before, but do you have a breadboard? Highly recommended for testing transistors in circuits.
You’ve probably seen the values in the component values table, but you must change some resistor values for OC81 transistors. This layout only works for OC75 or similar leaky transistors.
Thank you! :-) Then I'll get myself a breadboard. I normally built the circuit and use sockets for the transistors and relevant resistors to test them, but a breadboard would be easier of course.
ReplyDeleteSomething else, as you have many Germanium circuits on your website, would you be willing to make a layout of the Red Witch Fuzz God V1, which is Germanium?:
https://www.freestompboxes.org/viewtopic.php?t=1584&start=20
Fair enough. I had some early failures with transistors falling out of cheap sockets from Tayda, so I gave up on them and changed to a breadboard for testing. Also provides a chance to tweak a few other values, which can be fun.
DeleteFuzz God looks interesting - I’ll get on to that later.
I won’t do a layout for the fuzz god until I get around to breadboarding it. I’m unsure about the schematic and I don’t want to post something that might not work.
Delete