Tone Bender Mk2 Transistors?....

PaulPauliePabloPaolo

PaulPauliePabloPaolo

Member
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.
 

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Big Monk said:
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.
Click to expand...
Thanks so much for the info. ;)
Is there a place you would recommend buying them from?.
 
Big Monk said:
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.
Click to expand...
Does Q3 have to be leaky?
 
PaulPauliePabloPaolo said:
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.
Click to expand...
Hi Paul,

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

fig said:
Here’s the SB link;

smallbear-electronics.mybigcommerce.com

Transistor Set - TB Pro MK II PNP - Generic

New England's source for guitar pedals, pedal parts and electronics.
smallbear-electronics.mybigcommerce.com smallbear-electronics.mybigcommerce.com
Click to expand...
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.
 
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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.
 
ICTRock said:
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
Click to expand...
I was typing that…LOL

Edit: You put it more succinctly :)
 
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.
 
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andare said:
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.
Click to expand...
…and mind the pinout of the transistor.
 
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.
 
ICTRock said:
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.
Click to expand...
Thanks for the answer, and yea.... I too also suffer that kind of ocd when it comes to things like this...I'll be doing the same I'm sure!. ;)
I don't see any trimmers on the PCB for the Mk.2 from here, but maybe a picture of the inside of your build might help me understand where the biasing resistors go?. Im now presuming that specific resistors in the circuit will deal with biasing the transistors. SB are providing the resistor values that they recommend for those positions.
Hopefully all will become clear when things start turning up.

Thanks gang!... Stellar as always.
 
Big Monk said:
I wouldn't use those.

I had an email exchange with Steve when he was still running SBE and he admitted his bias points for the MK II follow the Fuzz Central voltages which are wrong.

When the transistors come on, post here on the forum and we can help you determine the best values to get Q1 and Q3 up over 7 vDC.
Click to expand...
Thanks very much! :)
 
So.... This was interesting!...
I ordered (and paid) 3 sets of transistors yesterday for the builds for myself and my friends with an online stock of 10sets.
Today I get an email from SBE saying they can only ship two, and how would I like to proceed with the additional money they took from my account?...Store credit or wait for availability of next shipment (whenever that might be!)?.
Not a great first experience with SBE!???... and what happened to all the other sets?. you b'stards!. haha

Should I...
A. Cancel the whole order out of protest of the 'treatment'.
B. Wait for them to get more stock?.
Or...
C. Just smash the place up, and then realise its only guitar pedals and have a beer.

Answers on a postcard! ;)

*I actually just read the email again in not so much of a fury and they said their head engineer is away until the 11th and will make more sets from then.

**And just a few hours after my response, I got another e-mail saying they have found another set.
I guess they are good guys after all as they put in the extra effort to rectify the situation and get another set together.
Bravo SBE. panic averted, the mission is still on!.
 
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