Sandspur Fuzz BC183- can’t bias Q2

[Had2Much2Think]

Trouble Biasing Q2 BC183 Sunface (PedalPCB Sandspur)

So I just got some more gain sorted BC183’s in and I decided to pull the BC108’s out of my Sandspur Fuzz (my first build btw, I think I’ve done about a dozen or so since then) and pop them in to see if I like it better than the BC108’s.

Q1 is a BC183A with an Hfe of around 180 and Q2 is a BC183L with an hfe of around 210-220. The highest I can get Q2 collector to bias to is 4.36v and that’s with the “sundial” external bias dimed as well as the internal bias trim.

I’d like to be able to get somewhere near 4.5v at 12 o clock on the sundial to give me a nice range of over/under bias to play with. How can I get it to bias higher? I’m not dying to desolder too much with this one but I will if I have too.

Any ideas on how to get some more juice to that Q2 collector? I haven’t actually played through it yet- I usually like to get the bias somewhere in the ballpark first and then plug it in and tweak it to taste. I’m pretty sure I got it too bias just fine with BC108’s- funny enough I think I struggled to get the 183’s to bias in my Twinface (Ge/Si switchable fuzzface) recently as well, I think I finally got it too bias with a 2N222 as Q2 but I’d like to use 183’s for both as I’ve heard good things about them.

Thanks y’all!

I appreciate any suggestions you can give me.

 

[DGWVI]

Are your transistors in backward?

 

[Had2Much2Think]

Are your transistors in backward?

I tried flipping them and Q2 read 9.2v and the bias controls wouldn’t touch it. I should probably go ahead and look up the 183 pin out though just in case as I’m not as familiar with them.

 

[Had2Much2Think]

I tried flipping them and Q2 read 9.2v and the bias controls wouldn’t touch it. I should probably go ahead and look up the 183 pin out though just in case as I’m not as familiar with them.

Are your transistors in backward?

The answer appears to be yes. Now I feel dumb.

Are your transistors in backward?

 

[DGWVI]

The answer appears to be yes. Now I feel dumb.

I asked because the 183s I have on hand are opposite pinouts from most of my 2N series transistors

Glad you got it workin

 

[harmaes]

The pinout of the L is indeed different

you can also try 2x BC183C of Around 500hfe or use a BC183B around 250hfe and a BC183C around 500hfe which is similar to the EJ fuzz which can biased cold around 3v or higher of course.

 

[Had2Much2Think]

The pinout of the L is indeed different

you can also try 2x BC183C of Around 500hfe or use a BC183B around 250hfe and a BC183C around 500hfe which is similar to the EJ fuzz which can biased cold around 3v or higher of course.

Aha! So the L is a different pinout from the A I’m using in Q1? I have some 183B’s- also some A’s and L’s- got a couple 184B and C that I got for the Sabbath Distortion that have very high Hfe’s- might be worth experimenting with. I’m kind of a lower gain fuzz guy, I usually prefer Ge but silicon has its place for sure!

 

[Had2Much2Think]

The pinout of the L is indeed different

you can also try 2x BC183C of Around 500hfe or use a BC183B around 250hfe and a BC183C around 500hfe which is similar to the EJ fuzz which can biased cold around 3v or higher of course.

The pinout of the L is indeed different

you can also try 2x BC183C of Around 500hfe or use a BC183B around 250hfe and a BC183C around 500hfe which is similar to the EJ fuzz which can biased cold around 3v or higher of course.

Yes! That solved it- had to bend the middle leg over and switch it with pin 3 and now it’s biasing just like it should. Thank you, I wouldn’t have even considered that the collector was in the middle and the base is on the side. Now let’s see how it sounds!