Hi there,
Yes, there will be a DIY Bone Bender, while for now I am currently waiting on parts to build some and define the circuit and also there will be a little tour through the circuit and a bit of history.
For the Sparkle Face and Bone Bender research projects I have taken the approach of setting bias so that transition from seemingly clean to distortion is gradual and symmetric, which in use means sounds can be set for near clean to full fuzz and gradually so with as low as possible static noises in the decay of a note.
The idea is to make a close to linear amplifier circuit that would overload symmetrically and gradually- that’d be a behavior you more expect from a tube amplifier than a fuzz pedal, but then back in the dawn of fuzzdom one of the things musicians wanted replicated with a fuzz pedal was an overdriven amplifier.
Now, back in the 1970’s there were theories of getting the tube amp response with germanium diodes and that due to the bended transfer curve that in a small segment could be likened to the transfer curve of a triode.
Indeed as the amplification is formed by the development of current through the emitter diode, germanium transistors would be able to get close and further since the bandwidth of germanium transistors is low and the raw gain is fairly low ( as compared to silicon transistors), the power bandwidth at full square output would result in slightly softened corners and that symmetrically to a square wave - much like suggested in the 1970’s the most desirable distortion of tube amplifiers would be: and thus a tube sound was suggested to be a square wave with rounded symmetrical edges and further to be dynamically controlled.
Oh yes I have seen this in some tube amps and most of the early tweed amps would do this: and thus transform from seemingly clean to square output with gently rounded corners.
So my approach to fuzz sound with these research projects is to recreate a desirable function albeit one from the dawn of fuzzdom.
Further specifically for the Bone Bender I also wanted to get a sustain of 2 seconds or longer
Most of the early fuzz and benders were crude in design meaning that they could differ greatly from unit to unit and generally the sound would be totally at the mercy of the transistors used.
For this reason I have serviced a number of fuzzes in my days were bias has drifted with the years locking the circuit……
Yes there would be less artifacts in the decay of Bone bender as compared with typical MK1 circuits and that due to some stabilization techniques that I have used to make a slightly cleaner sound but also longer sustain.
In industrial designs with transistors there’s been a number of stabilization networks developed to limit the influence of variance in the transistors used and with this in mind I have taken the approach of trimming each unit for the behavior I desire.
Note on Sparkle Face is that it comes with a trimmer so that behavior can be set as outlined above, and this can be done with a scope or simply by adjusting Q2 Collector to rest at 4,4 Volts or half the potential that collector return sees.
I have for the germanium circuits also used some filtering techniques mainly to limit wide band noise and thus get more fuzz and less noise at high volume levels
Note on Bone Bender is that it also comes with trimmers and those are set for longest a clearest sustain - as desired by Vic Flick a few pages back
However, quirks and artifacts in the decay can easily be set with the trimmers and e.g. by setting Q3 so that it is normally locked and only opens with signal- then you get switching noises from Q3 as it turns on and off.
At my age and having played so many old things and also recalling what I was thinking then about what I’d really want in sound: I really like to get less tape flutter from the tape delay and clearer decay from my fuzzes and…..
But yes I enjoy playing today some old fuzzes that make mostly noise……….the third element of music….
For the research projects in this thread I have built the fuzzes on Bearfoot pcb’s - a couple of multi boards that were developed with the benevolent and excellent aid of Bill Sicaras who made layouts for these with drawn circuits that had too many components and connections to allow several different circuits and thus there would not be one definite circuit flow but maybe ten different possible depending on what key would be used.
Arguably I’d possibly would build swifter on a perf board but a further idea for the research is that eventually some of the more popular choices should be able to be had also prebuilt and complete from Bearfoot- while that is looking into the future and first research and DIY with circuit explanations.
Right so while listening heavily to Hendrix will making fuzz pedals
I got thinking I’ll make a silicon FF too. Yes and Analoghog I was contemplating also your thoughts.
For that I decided to use transistor BC109C, which is an old favourite in Europe from the BC107, 108,109 series popular in the late 60’s and 70’s and then replaced by BC237,238 and 239 series, that also later was superceded by the BC547,548,549 series.
The series start with e.g the BC107A and B that are meant for high current switching and driving, and goes on with BC108A,B,C that are the general purpose medium types and lastly the BC109B and C that are the lower voltage and lower noise types meant for audio applications.
As a workhorse I usually use the BC550C that is an industrial type that can take high voltage and has low noise, but for Sparkle Face it might just look good with some metal cans
and so I made a unit with BC109C and for that employed a little different techniques of noise and quirks reduction, but I will say I feel the silicon version gets closer to what I am hearing with Hendrix- only something that has always amazed me is how Hendrix got a fuzz sound that was so clear and defined at points and then seemingly at will a wall of noise………but some of his rythm fuzz sounds are to my ear just amazing and something I could use for any type of music and that was my guiding start with the silicon version. Some of those will also be built and made DIY with explanations and I look forward to the feedback on all that eventually.
I’d say I’d rather like to make fuzz and bender sounds as I can hear them in my head than recreating faithfully old circuit diagrams- that much because I recall as a musician wanting to get the sounds out of head meanwhile playing gear that was almost there most of the time and sometimes that provided something magical but seemingly only so when the stars would align on an ordinary Tuesday.
That spurred the idea of controlling the the small things in sound that I find and found inspiring.
Much more to come and in the meanwhile have great fun
BJ