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I adjusted a few resistors and caps, and the Q3c voltage is like -8.05v
I don't what to make of Q2C: it really depends from the voltage divider, so i tried 180k (-1,2v) and 430k (-5v); i don't know what i like more, i can't decide.

Q1 is the strange one: it has very low hfe and leakage, but everything works. i tried to reach the suggested voltage (around -1v) changing the bias resistor, but i only get to -0,4v with a 4,7M resistor. There is a noticeable effect though, it doesn't SAG anymore.
With 1M on Q1B i had a HUUUUGE Sag, i wasn't expecting this (but i like it).
Is this suppose to happen?

I forgot: my transistors are

Q1 = MP40B, 30hfe, 20mA L

Q2 = gt308b, 64hfe, 5mA L

Q3 = MP42 , 52hfe, 50mA L

Hfe depends on collector current at which current Hfe was measured.
The unit for the leakage current is certainly Microamps not Milliamps.

I know it’s stretching back a long time... (10 years!) but I was wondering if anyone has a copy of the schematic for the silicon MK1 sonicVI posted back on page 7, I’ve tried using the internet way back machine to get a copy of it but sadly the link is dead .

you could probably trace it from the gutshot in this reverb listing

Ever since I got to play through a genuine MK I Tonebender, I have been chasing that sound. There are lots of pedals that come close, but none sound and feel like an original MK I. Unfortunately I don't have thousands to fork out for an original specimen, so I set out to build one. It has turned out to be a monumental task. I've been building pedals for a few years now so I figured it wouldn't be THAT tough right? Wrong! The circuit itself is easy....it's the tuning of said circuit that is a pain in the ass.
I have heard people talking about "simulating leakage" with a 1M resistor to help with biasing. Could someone please explain how to do that? ....and how it works exactly? Also, I haven't really been able to find any information about voltages or gain (hfe) targets. ANY information or tips concerning this circuit would be greatly appreciated!

Use this method to work out how and leakage of your transistors.

http://tagboardeffects.blogspot.com/201 ... r.html?m=1

Then add resistance across the base and collector until the leakage reading is in the correct range. Check hfe during the process.

andy-h-h wrote: ↑26 Oct 2020, 08:21 Then add resistance across the base and collector until the leakage reading is in the correct range. Check hfe during the process.

Thanks!
I have a transistor tester that gives me hfe and leakage readings.....so I assume I can use it while adding resistance across the base and collector to adjust leakage?

Yep - even better if you have proper test gear.

Remember the Stones' Statisfaction was only released June 5th of 1965...

In September of 1965 the Sola Sound Tonebender features prominently in Beat Instrumental magazine, with a full page ad and a big Fuzz giveaway:

And one of the winners of that competition was tracked down more recently by Macari's, who reacquired the pedal for their own collection.

There's more general (and verifiable!) historical information about the 'MKI' here: https://fuzzboxes.org/tonebendermki

nightraven wrote: ↑05 Nov 2021, 15:14 And one of the winners of that competition was tracked down more recently by Macari's, who reacquired the pedal for their own collection.

Contact these people to hopefully score one of these yourself

As if not enough stompbox collectors were bothering those people

I was really joking, just to find my own post reported to myself by nightraven for exposing these people while he's already contacted 3 of them himself.
I did not publish the names, the magazine did. Now at least the hunt is open to everybody rude enough to bug these old people...
This is the whole schematic hysteria all over again. Over a stupid square wave fuzz...

There's nothing to hunt -- if any of the other (surviving) dudes on the list still owned the pedals, then the pedals would've prized away by Ant Macari or me by now. It really is just a courtesy thing, because they're already aware of the mistake they made, not holding onto what are now £5000+ artifacts, without getting spammed any further.

nightraven wrote: ↑06 Nov 2021, 22:31 There's nothing to hunt -- if any of the other (surviving) dudes on the list still owned the pedals, then the pedals would've prized away by Ant Macari or me by now. It really is just a courtesy thing, because they're already aware of the mistake they made, not holding onto what are now £5000+ artifacts, without getting spammed any further.

What about the 12 other pedals? Please share some information!

modman wrote: ↑06 Nov 2021, 23:11

nightraven wrote: ↑06 Nov 2021, 22:31 There's nothing to hunt -- if any of the other (surviving) dudes on the list still owned the pedals, then the pedals would've prized away by Ant Macari or me by now. It really is just a courtesy thing, because they're already aware of the mistake they made, not holding onto what are now £5000+ artifacts, without getting spammed any further.

What about the 12 other pedals? Please share some information!

Are you referring to the contest in Melody Maker, in Spring 1966? I'd imagine that the 'MKI' had been discontinued by then, because we know for certain (based off an verifiable owner's testimony) that the 'MK1.5' was already available. I don't think the winner's list was published for that one though.

You gotta love the internet sometimes. It's great for digging up old documents.

I know I'm a bit late with this post, but I've gone through the thread multiple times and I'm seeing conflicting reports on ideal Q2 leakage: some are reporting that Q2 works well with very low leakage (if Q1/Q3 are sufficiently leaky), while others have suggested that Q2 requires moderate leakage, or even high leakage.

In my current build-in-progress, I have Q1 at 65 with 350uA leakage, and Q3 at about 100 with 400uA leakage. If my Q2 is very low leakage (100uA or lower) but is sufficiently high in gain (120-130 Hfe), would that work well within the circuit? I should note that I'm using a 470K for the Q2 to power rail.

I'd appreciate clarification and thoughts here. Thanks.