bc109 trannys and old Gibson/Maestro FZ-1A Fuzz tone !

[bluedreamin]

Hey all , got some questions ..what is the deal with bc109b transistors ? I have tried them in my wah and they are wimpy to say the least ! The pinout is correct but they sound terrible ! I have heard so many good things about them , what could be the problem ? I've also dug out this old Fuzz Tone from the closet which I have forgotten about ...gettin old I guess ...it doesn't "fuzz" anymore ! The switch does work , it just doesn't have the fuzz ! Transistor maybe ? Any help would be greatly appreciated ! Thanks     

[formerMember1]

..what is the deal with bc109b transistors ? I have tried them in my wah and they are wimpy to say the least !

that is scary for me, cuz those are the transistors that i was planning on using in my wah wah, which is one of my next projects.
I always heard that they were great, sure nothing else is wrong valued in the rest of the circuit?

[bluedreamin]

The stock trannies work well and the wah then sounds like it should but with the bc's in there , hardly any wah sound ! Everybody seems to love them and says how much they wake up their wah ..not here !

[Yun]

No satisfaction for you anymore eh 

Ummmm, is it just a clean signal that comes through on your fuzz-tone eh?  Hmmmm

Are they NPN or PNP's eh? 

PM me, man.  i might trade youse a Maestro super-Fuzz tone for your old broken one.  If that'd be cool with youse  ....PM me either way and let me know Yeah, or Neah so i know what's up, you know?

[bluedreamin]

  Thanks for the offer but I've had it for many years and would like to get it up and running again , have any ideas ? Yes , all I get is a clean signal , I don't know if the trannys are npn or pnp ?? Do you think they may be the problem ? Thanks !                                                                                                                           

[gez]

   Yes , all I get is a clean signal , I don't know if the trannys are npn or pnp ?? Do you think they may be the problem ? Thanks !                                                                                                                           

Take a DMM to it and check that power is getting through to the circuit.  Might be something as simple as dry joint, break in battery lead(s) or input/output lead etc...

[bluedreamin]

Hello there Gez , I do have power to the board although the wire used in this is not stranded but solid and very brittle . What would be your first suspect in this situation ? Also , any thoughts on why these bc109 transistors just aren't doing what I had expected , seems like many people love them ! ? Thanks for your time !

[Paul Perry (Frostwave)]

OK, you have replaced the original transistors with BC109Bs... what were the original transistors, and how did the unit sound before you replaced them??
I fthe original circuit is http://www.geofex.com/FX_images/fz1sch.gif then, you have replaced PNP by NPN.. that ain't gonna work, nohow.

[gez]

Hello there Gez , I do have power to the board although the wire used in this is not stranded but solid and very brittle . What would be your first suspect in this situation ?

The schematic for the 1a is here (scroll down a bit):

http://www.muzique.com/schem/index.html

Work though it with an audio probe and you should be able to find if there are any breaks in the chain before/between/after stages.  Tap the emitter of Q1 and the collectors of Q2 and Q3 to see if you're getting signal. 

If nothing obvious shouts out to you why it's not working take voltage measurements for all the trannies (emmiter, base and collector) with reference to ground (the + connection of the battery) and post them, though bias will vary from device to device so it's only a little helpful…

[gez]

PS Replace those 1u polarised caps first, they must be ancient!

[bluedreamin]

I will do this Gez ! Hello Paul ...sorry the bc109's I speak of are what I tried in my wah and was not impressed at all , whats all the fuss about them ?   

[Mark Hammer]

On my wah (which uses MPSA18 rather than BC109b), I was initially very disappointed.  I learned from a number of postings, however, that I needed to adjust the gain of the first transistor by tweaking the value of the emitter resistor to ground.  You'll find a whole lot of variation in the values posted for different designs, but they generally all end up being under 2k and often under 1k in value.  Might be worth sticking a 220R fixed resistor and 2k trimpot in there so you can find what works best in your own pedal.  I know it made one heck of a difference in my case.

[bluedreamin]

Mark, would that be the resistor that controls bass/gain or another one ?

[bluedreamin]

Hey Gez , I could use non polarized 1uf caps , correct ? 

[gez]

Hey Gez , I could use non polarized 1uf caps , correct ? 

No problem...

[Paul Perry (Frostwave)]

Ah, I was confused by the subject heading (  bc109 trannys and old Gibson/Maestro FZ-1A Fuzz tone ! ).
For some inexplicable reason I thought it might be about bc109 trannys IN an old Gibson/Maestro FZ-1A Fuzz tone.
It's very very unlikely that the transistors are the problem in the fuzz, if it has just broken (without being hacked at with a soldering iron). Broken wires, bad contact or short in the jacks much more likely. Partly dried electrolytics should still let some signal thru.

[bluedreamin]

Sorry for the confusion...I should have posted them seperately ! I do get signal just no fuzz whatsoever , do these 1uf caps HAVE to be electrolytic ...can they be film ? As always , thanks for your time guys !!!

[Paul Perry (Frostwave)]

Film is fine, it's just the expense and bulk. The more I think about it, it could well be the caps, if nothing else is obviously damaged/missing.

[gez]

I do get signal just no fuzz whatsoever

Ah, didn't realise this so there was no need for the audio probe advice.  As Paul said, try the caps first.  Failing that the pot which controls the amount of fuzz might be playing up. 

[bluedreamin]

Well guys , the caps did nothing for the fuzz and it appears the pot is working fine and does work ! I'll give it one more go if you all have any other suggestions ? What is really frustrating is how brittle everthing is , especially the solid core wire ...ya can't even look at it wrong and it breaks !