I've got a tonebender MK1.5 on the breadboard and trying different transistors and hfe,leakage combinations. I've never played, let alone heard an actual tone bender MK1.5 to base the sound on, so I ask what hfe, leakage, and voltage ranges should I work on to get close to an actual tone bender MK1.5 tone. So, far from the breadboard, it is not as trebly and gated than the MK1 and not as flabby, and muddy as a fuzz face.. Is this roughly how it should sound? Im using AC125 for this build.
(http://1.bp.blogspot.com/-IVgQG0XRTCw/T2mwj3f-BMI/AAAAAAAABKk/AiZ72qURaLw/s1600/mk15schema.jpg)
(http://i1261.photobucket.com/albums/ii594/bluesguitar65/IMG_0998_zps1fe02153.jpg)
I've never heard an original MK I. That said, the electrolytic caps in any antique that happens to still be running have probably shifted in value and leakage so much that the pedal does not sound today the way it once did. The circuit Is that of a classic FF, with a somewhat higher Collector load resistance for Q1. So I would suggest the usual "ideal" specs for the transistors: Q1 75 to 90, Q2 120 to 145, both with the lowest leakage you can find. Tweak the resistances for 4.5 Volts at Q2 Collector and see if the result makes your fur stand up.
Quote from: smallbearelec on April 05, 2013, 06:20:28 AM
I've never heard an original MK I. That said, the electrolytic caps in any antique that happens to still be running have probably shifted in value and leakage so much that the pedal does not sound today the way it once did. The circuit Is that of a classic FF, with a somewhat higher Collector load resistance for Q1. So I would suggest the usual "ideal" specs for the transistors: Q1 75 to 90, Q2 120 to 145, both with the lowest leakage you can find. Tweak the resistances for 4.5 Volts at Q2 Collector and see if the result makes your fur stand up.
Thanks!! So lower leakage just like tunning a fuzz face....makes sense since the circuit is identical to the fuzz face.