Tone Bender Mk2 Transistors?....

[PaulPauliePabloPaolo]

Hey Gang,

Thought Id show you what turned up today after its 3358m trip.... 3 sets (2 pics each as I turned the packets round so you could see the transistor).

Wondered if you guys could 'clue me in' to what I have, and what you think about the sets. Which set you'd prefer, and why?.
Seems like a few different types going on here, but some of the usual suspects turned up OC71, OC75, OC77 (mil spec?).
Which set would you keep for yourself?. and why!?!?!?!
Seems like they're all obeying the ratios of gain that have been discussed here.... Q1&2 ~ 60 and Q3 ~ 120.

Waiting for the PCBs to get here so I can start putting these beaut's together and make some sweet sweet solo's.

Let me know what you think.... and thankyou again for the wealth of knowledge and comedy that I have found here!.
P.

 

[PaulPauliePabloPaolo]

Hey Ya'll,

I just wanted to check the values for the biasing resistors and see if there was any advice on doing this?... before I get too excited and start soldering things in....
Im starting with the set below (set 3 from previous. post).
I did notice that the resistors use a slightly different designation from the schematic provided for the build docs and the one listed on the packet below. (prob. cause of the power inversion network).
A. R3 on the Transistor packet (47K) seems to correspond to R5 on the build docs (100K).
B. R4 on the Transistor packet (100K) seems to correspond to R4 on the build docs (100K).
C. R6 on the Transistor packet (8K2) seems to correspond to R7 on the build docs (8K2).

So my question would be what to follow on the first resistor?... And how to determine this. Obviously I think the general opinion would be to follow the Transistor packet and use a 47K for R5?.

Hope you can help.... my trigger finger is itchy.

 

[andare]

While we wait for the experts to chime in I'll just suggest you breadboard the circuit and see for yourself. I did and the 3 transistors I chose from my stash, with somewhat standard gain, all bias in the ballpark and the circuit sounds great.

Breadboarding is a game changer. You can build any circuit quickly and non destructively. If it sounds bad you can reuse the components and never buy the PCB for a pedal you won't enjoy. The tutorials on this forum are what got me started.

 

[PaulPauliePabloPaolo]

While we wait for the experts to chime in I'll just suggest you breadboard the circuit and see for yourself. I did and the 3 transistors I chose from my stash, with somewhat standard gain, all bias in the ballpark and the circuit sounds great.

Breadboarding is a game changer. You can build any circuit quickly and non destructively. If it sounds bad you can reuse the components and never buy the PCB for a pedal you won't enjoy. The tutorials on this forum are what got me started.

Thats a really good point!.... I don't have a breadboard but I will get one. These smaller circuits seem like they wouldn't be too complicated to lay out, and as you say... I actually could have a listen prior to soldering.
Also just popped into my mind... You guys all socket the transistors?.

 

[ICTRock]

Thats a really good point!.... I don't have a breadboard but I will get one. These smaller circuits seem like they wouldn't be too complicated to lay out, and as you say... I actually could have a listen prior to soldering.
Also just popped into my mind... You guys all socket the transistors?.

I don't but you certainly can. Some guys take the transistors with them when they find a good set.

 

[andare]

I socket transistors but I'll probably stop soon unless they're really expensive or hard to find.

 

[PaulPauliePabloPaolo]

Are we saying that the procedure for finding the correct values is to breadboard the circuit first?
As I currently don't have a breadboard (I will get one and learn how to use it), would another solution be to put sockets on the R5 resistor lugs and experiment between 47K and 100K until I find what I like sonically?.... (or until the voltage is correct?... best values to get Q1 and Q3 up over 7 vDC.).

 

[Coda]

Are we saying that the procedure for finding the correct values is to breadboard the circuit first?
As I currently don't have a breadboard (I will get one and learn how to use it), would another solution be to put sockets on the R5 resistor lugs and experiment between 47K and 100K until I find what I like sonically?.... (or until the voltage is correct?... best values to get Q1 and Q3 up over 7 vDC.).

Yes. Make sure that you correctly identify the pcb component, though. Compare the schematics so you know which component is which; the ID’s for the PPCB board may not match the schematic used to bias your transistors…

 

[PaulPauliePabloPaolo]

Ahhh ok.... As I said, I don't have one, and I don't know how to use one, but I will get one and go through the instructional material.

Good point about identifying the components, I did go through them with my limited knowledge and experience and I came up with....

A. R3 on the Transistor packet (47K) seems to correspond to R5 on the build docs (100K).
B. R4 on the Transistor packet (100K) seems to correspond to R4 on the build docs (100K).
C. R6 on the Transistor packet (8K2) seems to correspond to R7 on the build docs (8K2).

Could anyone confirm that?.

Anyone got any thoughts on how to proceed without a Breadboard? is Socketing R5 a viable 'workaround'?.
I do have a DMM and an M tester.

 

[PaulPauliePabloPaolo]

Hey gang,
Just wanted to make sure I get the orientation of the transistors correct.
Very kindly SBE gives the red dot as the collector.... but on the silkscreen there is no CBE markings, but there is a 'tab' next to the socket like you would have on metal can transistors. As stated before I am not using OC81's, but OC75's and an OC71.
They are not the metal can type but I do see on the web that the 'tab' is usually next to the emitter.

I just wanted to make sure before I install them.
Also I tested them quickly with an M Tester and they all test as resistors.... Is this something 'normal'... just seemed a little strange as Ive tested a few Si transistors and they tested fine and gave me the pin out correctly.

Thanks in advance, and I will await the wisdom of the forum!.
P.

 

[PaulPauliePabloPaolo]

Thanks guys!... Victory!.... I just can't believe how great it sounds!!!... Instant Page, Ronson & Townshend!....
PPCB are undoubtably my favourite source for all things like this, unbelievable quality at a price that makes it possible for 'normal folk' like me and my friends to enjoy these circuits without a 2nd mortgage!.
I am in heaven tonight!.... and no stairway required!.

 

[andare]

Thanks guys!... Victory!.... I just can't believe how great it sounds!!!... Instant Page, Ronson & Townshend!....
PPCB are undoubtably my favourite source for all things like this, unbelievable quality at a price that makes it possible for 'normal folk' like me and my friends to enjoy these circuits without a 2nd mortgage!.
I am in heaven tonight!.... and no stairway required!.

So you managed. Enjoy!