# Woodpecker Tremolo Q2 2N2646 Orientation



## TCHarley (Feb 22, 2019)

Hi guys.

I am building a woodpecker tremolo and Q2 is a 2N2646. I ordered this part from Small Bear Electronics because that is the only place I could seem to find it. When it came time to solder it in it came to my attention that in order for the tab and the pins to match the printing the PCB, I would have to insert my 2N2646 in from the bottom of the PCB.  Is this what I should be doing? 





The "bottom view" shown there matches what is o the top side of the PCB, identifying the pin holes. If I insert from the top of the board as I would have expected it to go, the tab would be on the wrong side and Base 1 and Base 2 would be swapped.

Thanks in advance


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## Robert (Feb 23, 2019)

This one has been a total nightmare.    

Ignore the metal tab on the silkscreen, it is not a reliable way to determine the correct orientation.   The 2N2646 _apparently_ has more than one pinout.  

For the one sold by Smallbear you can bend the Emitter lead back between the B1 and B2 leads to make it fit on the top of the board properly.


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## TCHarley (Feb 23, 2019)

Robert said:


> This one has been a total nightmare.
> 
> Ignore the metal tab on the silkscreen, it is not a reliable way to determine the correct orientation.   The 2N2646 _apparently_ has more than one pinout.
> 
> For the one sold by Smallbear you can bend the Emitter lead back between the B1 and B2 leads to make it fit on the top of the board properly.


I thought that it might have been trouble based on the differences between the pcb diagram and the pcb itself. Thanks a lot for the help!


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## jjjimi84 (Mar 20, 2019)

Does yours make a percussive tap all the time? Kinda loud no matter the settings?


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## TCHarley (Mar 20, 2019)

jjjimi84 said:


> Does yours make a percussive tap all the time? Kinda loud no matter the settings?


Yes it does! I just finished it the other night and tested, and haven't had a chance to go back to it. Any idea what to do?


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## jjjimi84 (Mar 20, 2019)

TCHarley said:


> Yes it does! I just finished it the other night and tested, and haven't had a chance to go back to it. Any idea what to do?



I was hoping someone else had an idea. I am not a big tremolo guy so this just went onto the shelf.


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## chongmagic (Mar 20, 2019)

I have the same issue. I have built two with the same result.


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## Robert (Mar 20, 2019)

This one has been nothing but a struggle.... There have been a few successful builds, but far more failures than successes....

I received PCBs for the new version (V4) yesterday, just waiting for parts to arrive so I can build one and check it out.

The circuit has changed a bit, this one uses an in-production transistor instead of the 2N2646.


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## TCHarley (Mar 20, 2019)

Robert said:


> This one has been nothing but a struggle.... There have been a few successful builds, but far more failures than successes....
> 
> I received PCBs for the new version (V4) yesterday, just waiting for parts to arrive so I can build one and check it out.
> 
> The circuit has changed a bit, this one uses an in-production transistor instead of the 2N2646.


So is there nothing I can do with the one I've got?


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## chongmagic (Mar 20, 2019)

I


TCHarley said:


> So is there nothing I can do with the one I've got?


In regards to the ticking?


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## TCHarley (Mar 20, 2019)

chongmagic said:


> I
> 
> In regards to the ticking?


Yeah, the popping in mine is quite loud


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## Robert (Mar 20, 2019)

TCHarley said:


> So is there nothing I can do with the one I've got?



No no, I wasn't suggesting that.

I don't have one of these built at the moment to try this myself, but if you're feeling experimental....

Try each one of these modifications one at a time, test it after each one and see if there is any improvement.


Remove R3 (100K)
Disconnect lug 3 of the Depth pot, reconnect it using a 1uF electrolytic cap. (Positive lead to the Pad, Negative lead to Lug 3 of the pot)
Increase the value of R7 (currently 470R) to 1K - 2K2.
Increase the value of R6 (currently 39R) to 100R
Let me know if any of this helps.


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## TCHarley (Mar 20, 2019)

Robert said:


> No no, I wasn't suggesting that.
> 
> I don't have one of these built at the moment to try this myself, but if you're feeling experimental....
> 
> ...


Okay will do.


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## jjjimi84 (Mar 21, 2019)

It took every mod to get mine sounding with less ticking. I also think R5 sound be R7.


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## Robert (Mar 21, 2019)

jjjimi84 said:


> It took every mod to get mine sounding with less ticking. I also think R5 sound be R7.



Ahh you're right.  Corrected.  

So how much of an improvement did this make?   Is it "acceptable" now, or still ticking?


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## jjjimi84 (Mar 21, 2019)

It is acceptable, I think there is some inherent wonkiness with this pedal. I think the 1uf helped the best and on the slow speeds it sounds pretty good the other side of the rate switch isn't my bag.


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## Dice1012 (Mar 27, 2019)

Got the same ticking problem with the one I just finished.


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## Dice1012 (Mar 27, 2019)

Robert said:


> No no, I wasn't suggesting that.
> 
> I don't have one of these built at the moment to try this myself, but if you're feeling experimental....
> 
> ...


what were those resistor locations? I just want to clarify before I start any modifications.


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## Robert (Mar 27, 2019)

The ones listed in post #12 should be correct now.


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## Dice1012 (Mar 27, 2019)

Robert said:


> The ones listed in post #12 should be correct now.


Thanks


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## chongmagic (Mar 27, 2019)

I will try these on my build and will report back as well.


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## Dice1012 (Apr 14, 2019)

Robert said:


> No no, I wasn't suggesting that.
> 
> I don't have one of these built at the moment to try this myself, but if you're feeling experimental....
> 
> ...


Ended up doing all the mods listed. Still has audible ticking noise.


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## falzhobel (Nov 21, 2019)

I've built 4 of those and no ticking in mine. Is the new PCB revision the answer to the trouble ?


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## chongmagic (Nov 21, 2019)

falzhobel said:


> I've built 4 of those and no ticking in mine. Is the new PCB revision the answer to the trouble ?


The new revision solves the issue. It gets rid of the picky transistor, the 2n2646 with a modern tranny.


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