Pedals w/ clipping diodes: Matching vF?

[fuzz]

So, I read a couple posts about how some pedals with multiple transistors need to be matched (for octave properties) but what about clipping diodes? I suspect I am overthinking on the subject along with a lack of knowledge on said subject...

What about a pedal that has 2 x Ge clipping diodes. I have a drawer of Ge diodes and their vF's are all over the place. For a basic fuzz pedal with two transistors and two clipping diodes, is there a rhyme or reason to matching diodes? Any benefit?

 

[Brett]

With silicon diodes, you'd match them if you wanted tightly matched symmetry or a specific asymmetrical configuration.

With germanium, you can match the forward voltage but you'd also want to consider (and match) leakage if attempting to do the same as above.

 

[fuzz]

Ah man, I never even thought to test leakage lol. I don’t think my Peak tests this…

 

[Cybercow]

So, I read a couple posts about how some pedals with multiple transistors need to be matched (for octave properties) but what about clipping diodes? I suspect I am overthinking on the subject along with a lack of knowledge on said subject...

What about a pedal that has 2 x Ge clipping diodes. I have a drawer of Ge diodes and their vF's are all over the place. For a basic fuzz pedal with two transistors and two clipping diodes, is there a rhyme or reason to matching diodes? Any benefit?

IME, clipping elements (diodes, transistors, etc) with manually matched forward voltage drops make little difference from simply matching the part numbers. While test equipment can measure minute differences, the difference will never be audibly noticalble. Such is the nature of dirt circuits that employ clipping elements.

Matching transistors and/or diodes in dirt circuits is typically reserved for ring modulator and octave builds. With regard to fuzz, distortion or other dirt circuits that use clipping devices, even Ge diodes of the same type ID but varying Vfd's, the ability to discern the difference between "matched" and unmatched elements is an exercise in cork sniffing. Due to the amount of random harmonics and distortion, I don't see (hear) how it's possible to tell the difference in a dirt circuit.

What really makes an audible difference in clipping elements is an intentionally asymmetric configuration of clippers as opposed to a symmetrical configuration.

So, IMO, you are correct in that you may be overthinking it.

 

[fuzz]

So, IMO, you are correct in that you may be overthinking it.

 

[jwin615]

Some good info here on octave up fuzzes

David Morrin - Octave Up

Octave Up Fuzz Topologies Transformer to Diode Frequency Doubler Fuzz Push-Push Amp Frequency Doubler Fuzz BJT to Diode Frequency Doubler Fuzz Ring Modulator Fuzz? Op Amp Frequency Doubler Fuzz A Brief History of the Octave Up Fuzz Effect Purple Haze (1967) In early 1967, Roger Mayer was helping

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