Tone Bender Mk2 Transistors?....

[PaulPauliePabloPaolo]

Hey Gang,

Just a quick one about what kind of Ge. transistors are you guys using for the Tone Vendor? I want one and some friends have asked me to build one for them also.
Ive looked through the forums and many of the places recommended such as Small Bear have sold out of the OC81D, or indeed any 'match sets' that they supply.
From my research I have found that many say that you could use many different types for this pedal and they really only have to satisfy some conditions such as Q1 & Q2 being ~ 60-70hfe, and Q3 ~120hfe.... and that Q3 should be 'leaky'.

So the question is... Where are you guys getting yours?... is there any up to date recommendations of where to get suitable transistors for this project?.
Are there any recommendations of other types of transistors to use for this?
Obviously I'll be socketing them, and I have an M Tester to measure.

And just for S&G's here are the pedals Ive made from PedalPCB... Who doesn't like pics right!?!?!

Thanks in advance
P.

 

[Big Monk]

Hey Gang,

Just a quick one about what kind of Ge. transistors are you guys using for the Tone Vendor? I want one and some friends have asked me to build one for them also.
Ive looked through the forums and many of the places recommended such as Small Bear have sold out of the OC81D, or indeed any 'match sets' that they supply.
From my research I have found that many say that you could use many different types for this pedal and they really only have to satisfy some conditions such as Q1 & Q2 being ~ 60-70hfe, and Q3 ~120hfe.... and that Q3 should be 'leaky'.

So the question is... Where are you guys getting yours?... is there any up to date recommendations of where to get suitable transistors for this project?.
Are there any recommendations of other types of transistors to use for this?
Obviously I'll be socketing them, and I have an M Tester to measure.

And just for S&G's here are the pedals Ive made from PedalPCB... Who doesn't like pics right!?!?!

Thanks in advance
P.

In truth, as long as Q1 has at least 15 microamps leakage, nearly any transistors with hFE around 70 for Q1 and 100 for Q2,3 will sound good.

As a parallel, the MK II with silicon transistors is also phenomenal. As long as you put either a 470k-1M from base to power or base to collector, Q1 will conduct.

Some of the best I’ve made had local feedback resistors from emitter to ground and medium gain silicon transistors.

 

[PaulPauliePabloPaolo]

In truth, as long as Q1 has at least 15 microamps leakage, nearly any transistors with hFE around 70 for Q1 and 100 for Q2,3 will sound good.

As a parallel, the MK II with silicon transistors is also phenomenal. As long as you put either a 470k-1M from base to power or base to collector, Q1 will conduct.

Some of the best I’ve made had local feedback resistors from emitter to ground and medium gain silicon transistors.

Thanks so much for the info.
Is there a place you would recommend buying them from?.

 

[andare]

In truth, as long as Q1 has at least 15 microamps leakage, nearly any transistors with hFE around 70 for Q1 and 100 for Q2,3 will sound good.

As a parallel, the MK II with silicon transistors is also phenomenal. As long as you put either a 470k-1M from base to power or base to collector, Q1 will conduct.

Some of the best I’ve made had local feedback resistors from emitter to ground and medium gain silicon transistors.

Does Q3 have to be leaky?

 

[fig]

Hey Gang,

Just a quick one about what kind of Ge. transistors are you guys using for the Tone Vendor? I want one and some friends have asked me to build one for them also.
Ive looked through the forums and many of the places recommended such as Small Bear have sold out of the OC81D, or indeed any 'match sets' that they supply.
From my research I have found that many say that you could use many different types for this pedal and they really only have to satisfy some conditions such as Q1 & Q2 being ~ 60-70hfe, and Q3 ~120hfe.... and that Q3 should be 'leaky'.

So the question is... Where are you guys getting yours?... is there any up to date recommendations of where to get suitable transistors for this project?.
Are there any recommendations of other types of transistors to use for this?
Obviously I'll be socketing them, and I have an M Tester to measure.

And just for S&G's here are the pedals Ive made from PedalPCB... Who doesn't like pics right!?!?!

Thanks in advance
P.

Hi Paul,

You’ll also want to make certain you get PNP-type transistors for the TBMKII.

 

[ICTRock]

I believe smallbear announced transistor kits were available again

 

[Big Monk]

Does Q3 have to be leaky?

Nope. It helps if you are keeping the original stock circuit because you want the collector voltage up over 7.5 vDC, but you can just tweak the Q2 or Q3 collector resistor.

Leakage is not a benefit unless for some reason you want to keep the stock vintage circuit unmodified.

In all other cases it’s a hinderance.

 

[Big Monk]

Hi Paul,

You’ll also want to make certain you get PNP-type transistors for the TBMKII.

NPN works just as well and you can ditch the voltage inverter.

 

[fig]

NPN works just as well and you can ditch the voltage inverter.

Yes sir. They’ll just want to make sure the transistors match the schematic.

 

[Big Monk]

Yes sir. They’ll just want to make sure the transistors match the schematic.

Yes.

Word of note: Whatever transistors are used, make sure all polarized components match that polarity.

Just did graphics for the Monk Bender MK II last night so this was on my mind!

 

[fig]

Here’s the SB link;

Transistor Set - TB Pro MK II PNP - Generic

Guitar pedals, pedal parts and electronics.

smallbear-electronics.mybigcommerce.com

 

[PaulPauliePabloPaolo]

Thanks Gents,

Here’s the SB link;

Transistor Set - TB Pro MK II PNP - Generic

Guitar pedals, pedal parts and electronics.

smallbear-electronics.mybigcommerce.com

Thanks for that!... I was just going to post that link to ask if they were OK.... You beat me to it!...

And maybe a shockingly silly or just plain remedial question regarding the included 'biasing resistors'.
How do I utilise these?...

Thanks again for the enlightening answers guys!.
P.

 

[ICTRock]

you follow the included schematic regarding placement within the circuit ... now I was so OCD that I merely used the same values of resistors but in the same metal film 1% I was using in the rest of the circuit so everything looked the same. if any of them are where a bias trimmer would be you can A) set the bias trimmer to that resistance value or B) put that value resistor in there instead of a trimmer.

 

[fig]

you follow the included schematic regarding placement within the circuit ... now I was so OCD that I merely used the same values of resistors but in the same metal film 1% I was using in the rest of the circuit so everything looked the same

I was typing that…LOL

Edit: You put it more succinctly

 

[andare]

Since I'm on a breadboarding binge and you got me interested in Germanium again.
Say I have a silicon fuzz face and i want to use PNP Ge transistors in it. I flip the electrolytic caps and swap the + and - jumpers. Is that all? Isolated power supply of course.

 

[fig]

Since I'm on a breadboarding binge and you got me interested in Germanium again.
Say I have a silicon fuzz face and i want to use PNP Ge transistors in it. I flip the electrolytic caps and swap the + and - jumpers. Is that all? Isolated power supply of course.

…and mind the pinout of the transistor.

 

[andare]

…and mind the pinout of the transistor.

I will. I promise!

 

[andare]

So I just breadboarded a TB Mk2 with the stock values and it sounds great through a Protoboard Micro w/power supply and reverse polarity cable. Here's what I got for transistors, more or less:

Q1 (AC125) hFE 55, Iceo 150mA, Q1c 7.7
Q2 (ASY34S) hFE 100, Iceo 44mA, Q2c 0.37
Q3 (ASY34S) hFE 100, Iceo 34mA, Q3c 6.7

It sounds like a good Ge Fuzz Face but it doesn't clean up as well. Just dime both knobs and go to town.
No RF either. I guess the 10n input cap to ground killed the radio star.

 

[Big Monk]

So I just breadboarded a TB Mk2 with the stock values and it sounds great through a Protoboard Micro w/power supply and reverse polarity cable. Here's what I got for transistors, more or less:

Q1 (AC125) hFE 55, Iceo 150mA, Q1c 7.7
Q2 (ASY34S) hFE 100, Iceo 44mA, Q2c 0.37
Q3 (ASY34S) hFE 100, Iceo 34mA, Q3c 6.7

It sounds like a good Ge Fuzz Face but it doesn't clean up as well. Just dime both knobs and go to town.
No RF either. I guess the 10n input cap to ground killed the radio star.

Voltages?

 

[andare]

Voltages?

Q1-2-3c are the voltages.