SOLVED BC108 Fuzz Face Issues

[Fontelroy]

I'm getting a super awful ticking sound when I have the bias set at a normal level

https://soundcloud.com/ej-crough%2Farbiter-fuzz-issues

I've had this happen with 2 BC108 fuzzes now and I felt like I had to ask y'all for some help here...
When I set the bias by ear to get the ticking to go away it's quite low and causes that starved spitting sound which isn't my thing. Is this something related to the specific BC108b's I'm using?

 

[Big Monk]

It sounds like low level motorboating/oscillation.

Which board is this?

 

[Fontelroy]

SiliSmile Fuzz - PedalPCB.com

Compare to Arbiter Fuzz Face (Silicon)

www.pedalpcb.com

it's this guy but it's also happened to me on the BC108 side of the twinface

 

[Big Monk]

SiliSmile Fuzz - PedalPCB.com

Compare to Arbiter Fuzz Face (Silicon)

www.pedalpcb.com

it's this guy but it's also happened to me on the BC108 side of the twinface

What are you voltages like on Q1?

When it’s doing the bad sound, what’s the bias at on Q2?

Is the bad sound where the actual fuzz sounds the best?

Is the bad sound affected if you back the Fuzz control off ever so slightly?

 

[jesuscrisp]

From the picture it looks like the emitter of Q1 isn't properly soldered.

 

[Big Monk]

From the picture it looks like the emitter of Q1 isn't properly soldered.

Good eye.

@Fontelroy Snap some pics of the underside of the board for us as well and a close up of the Emitter on Q1.

 

[Fontelroy]

I double checked Q1, i think it's just a weird pic, the transistor is in there and i reflowed it just in case

 

[Fontelroy]

wait a minute!! that totally worked! it must have been that solder joint!!!

 

[Fontelroy]

I am getting some radio signal when I roll back my guitar's volume all the way now.... hmm....

 

[steviejr92]

I love reading these responses! @Fontelroy Awesome job on figuring it out!

 

[steviejr92]

Well i want to say Fuzzes are great Radio Receivers but that shouldn't be happening....

 

[Fontelroy]

https://soundcloud.com/ej-crough%2Fno-volume-issue

this is the sound now, sounds great!! but at the end when I dump my guitar's volume to zero its got some issues... could this be another solder issue?

 

[Big Monk]

I am getting some radio signal when I roll back my guitar's volume all the way now.... hmm....

That’s normal. Unbuffered Fuzz Faces do all kinds of weird shit.

 

[steviejr92]

I want to say that might be the nature of the beast....but i will let someone with more knowledge chime in!

What @Big Monk said!

 

[Big Monk]

https://soundcloud.com/ej-crough%2Fno-volume-issue

this is the sound now, sounds great!! but at the end when I dump my guitar's volume to zero its got some issues... could this be another solder issue?

No. That’s sounds like normal old school volume rolled off Fuzz Face behavior to me.

 

[steviejr92]

No. That’s sounds like normal old school volume rolled off Fuzz Face behavior to me.

Yup and this is why i thought the same thing. My FF does the same thing when the Volume is rolled off.

 

[Fontelroy]

well i reflowed some solder joints and the ticking is back... probably shoulda left it alone with the radio stuff lol

 

[andare]

well i reflowed some solder joints and the ticking is back... probably shoulda left it alone with the radio stuff lol

Clean your board, check the solder joints and reflow them again. Use heat sinks on the transistor legs. In the future maybe use sockets.

To "kill the radio star" you can put a small capacitor from input to ground, usually anything between 1n and 100n will work, cutting more and more high end as you go up in values. Play around.

 

[Fontelroy]

I've actually since switched q1 to a 2n3906 and it fixed everything! I had someone mention that bc108b can be too much gain and after testing out some different transistors in q1 I think I agree!

 

[Coda]

Clean your board, check the solder joints and reflow them again. Use heat sinks on the transistor legs. In the future maybe use sockets.

To "kill the radio star" you can put a small capacitor from input to ground, usually anything between 1n and 100n will work, cutting more and more high end as you go up in values. Play around.

On an Si FF the tradition is a very small value (I like less than 100p) from C to B at Q2. The higher the value, the more high end you’ll lose. Of course, at the same time, you want to make sure that you have a high enough value to stop/diminish the noise…