Tone Vendor MKI HFE

RCZ

Member
Where can I buy the 2SC381 ??

Wich HFE I must use in Q1, Q2 and Q3??

Could I use three OC75 instead 2SC381 ?

Thank you all, is my first fuzz
 

Mir9

New member
I hope you get some help here as the MK1's can be tough to get right, especially for a first fuzz. Leakage will matter here. You may want to buy a set already auditioned for you and even then, use sockets to keep experimenting.
 

Chuck D. Bones

Well-known member
You picked a good one to learn on. 😬 Q1 & Q3 are leakage-biased. Q1-E and Q3-C should be somewhere between -3V and -6V. The collector voltage on Q2 varies with the ATTACK setting. With ATTACK at zero, Q2-C should be near -9V. With ATTACK at 10, Q2-C should be somewhere in the middle, depending on what sounds good to you. Part number is unimportant, leakage and hFE are what matters. I agree with Mir9, buy a transistor set that was selected for a Tone Bender MK1. Otherwise, you will need to buy a bunch of them and select them yourself. Definitely install sockets.
 

RCZ

Member
You picked a good one to learn on. 😬 Q1 & Q3 are leakage-biased. Q1-E and Q3-C should be somewhere between -3V and -6V. The collector voltage on Q2 varies with the ATTACK setting. With ATTACK at zero, Q2-C should be near -9V. With ATTACK at 10, Q2-C should be somewhere in the middle, depending on what sounds good to you. Part number is unimportant, leakage and hFE are what matters. I agree with Mir9, buy a transistor set that was selected for a Tone Bender MK1. Otherwise, you will need to buy a bunch of them and select them yourself. Definitely install sockets.
Where can I Buy one set?
 

RCZ

Member
I know one shop in Spain who can sell me three OC75 with the hfe I need. Someone know what hfe it's okey?
 

Chuck D. Bones

Well-known member
You need two transistor parameters to be matched to the circuit: HFE & Icbo (leakage). Better buy 10 and hope you get three with the right properties. Or maybe build a different circuit. Consider the Scythe (Earthquaker Tone Reaper). I has only one Ge transistor and can produce similar tones to the Tone Bender MK 3.
 

zgrav

Active member
Note - "wanting to learn more about fuzz" can refer to building a pedal or to playing a fuzz pedal. A good fuzz to build if you want to learn about how to make it work, is not the same thing as a "good fuzz" to build if you want an easy project to build that will sound good. Learning how to make something work can be a project that will require more time and learning on your part. It can be more rewarding if you understand that is what you are choosing to do.

For a first fuzz project I would take CDB's suggestion to look at the Scythe.
 

Chuck D. Bones

Well-known member
Or build a Big Muff. Everybody ends up owning some of those. They're iconic and not hard to build and make work. Listen to some demos first, because the various versions are tuned differently.
 
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