Your favorite silicon transistor?

[caiofilipini]

Just wanted to ask folks what are their favorite silicon transistors for a classic fuzz sound. I just finished building an NPN Sunflower as I had a few BC108C lying around, but I'm not sure I like how they sound. I think they might be a tad too gainy for my taste.

I ordered some BC108B and BC183, but I figured I should ask here and maybe get some other options.

Thanks!

 

[Thirsty Ant]

BC173

 

[HamishR]

It's so circuit dependant. What works wonderfully in one circuit may be awful in another.

 

[caiofilipini]

It's so circuit dependant. What works wonderfully in one circuit may be awful in another.

Good point. It's a Sunflower (Fuzz Face) in this case.

 

[Chuck D. Bones]

HFE affects the bias in a FuzzFace, up to a point. Once the HFE gets high enough, it doesn't matter any more. Since the Sunflower contains internal and external BIAS controls, you should be able to dial-in the sound you want with just about any Si transistor. I prefer the low-noise transistors like BC549, BC550, MPSA18, 2N5088, 2N5089 & 2N5210. BC108 and BC109 are not particularly low-noise, but they show up in plenty of good-sounding pedals. Vintage pedal builders had a much smaller number of transistors available compared the the options we have today. You can always install sockets and audition the various transistors. I would expect a BC108B and BC108C to sound pretty much the same in a Sunflower once the bias is dialed-in.

 

[caiofilipini]

HFE affects the bias in a FuzzFace, up to a point. Once the HFE gets high enough, it doesn't matter any more. Since the Sunflower contains internal and external BIAS controls, you should be able to dial-in the sound you want with just about any Si transistor. I prefer the low-noise transistors like BC549, BC550, MPSA18, 2N5088, 2N5089 & 2N5210. BC108 and BC109 are not particularly low-noise, but they show up in plenty of good-sounding pedals. Vintage pedal builders had a much smaller number of transistors available compared the the options we have today. You can always install sockets and audition the various transistors. I would expect a BC108B and BC108C to sound pretty much the same in a Sunflower once the bias is dialed-in.

I did install sockets and did experiment with both the internal and external bias controls, as well as the internal clean trimpot. I'll experiment some more and test the new transistores when they're here. I believe I have some BC549 around here somewhere too, I'll make sure to include them in the tests. I'll report back in a few days.

Thanks, Chuck!

 

[Betty Wont]

the 2n3700 is my favorite for this type of application.

 

[caiofilipini]

the 2n3700 is my favorite for this type of application.

Thank you!

 

[Chuck D. Bones]

For a little added fun, try a BS170 or 2N7000 for Q2. It will bias ok, just mind the pinout.

 

[caiofilipini]

For a little added fun, try a BS170 or 2N7000 for Q2. It will bias ok, just mind the pinout.

Oh interesting, I have some BS170s around too, I'll put them in the testing mix. Thanks!

 

[Iago]

Just wanted to ask folks what are their favorite silicon transistors for a classic fuzz sound. I just finished building an NPN Sunflower as I had a few BC108C lying around, but I'm not sure I like how they sound. I think they might be a tad too gainy for my taste.

I ordered some BC108B and BC183, but I figured I should ask here and maybe get some other options.

Thanks!

For a silicon FF: BC108B, BC109B or 2N2222 (never tried too many of the modern transistors though)
For a Big Muff: BC550C (I find these usually too gainy for FF's)

But as other people mentioned, it's more like a matter of Hfe: In my experience, higher HFE = gainier and brighter, sometimes too bright
Lower hfe = lower gain and darker, smoother - but sometimes too low gain.

It's all about finding the balance you want, often by mixing and matching. I have an AC125 and GT308 on my DIY '69 Fuzz build.

I like Hfe's between 200-350 for a Si Fuzz Face. Hfe's of old transistors may vary quite a bit. I've found that more modern transistors like 2N5088 or 2n5089, BC549, BC550B or C, BC184's, 2N3904 don't vary so much and are more dependable. Old ones are sometimes quiet, sometimes noisy.

 

[caiofilipini]

For a silicon FF: BC108B, BC109B or 2N2222 (never tried too many of the modern transistors though)
For a Big Muff: BC550C (I find these usually too gainy for FF's)

But as other people mentioned, it's more like a matter of Hfe: In my experience, higher HFE = gainier and brighter, sometimes too bright
Lower hfe = lower gain and darker, smoother - but sometimes too low gain.

It's all about finding the balance you want, often by mixing and matching. I have an AC125 and GT308 on my DIY '69 Fuzz build.

I like Hfe's between 200-350 for a Si Fuzz Face. Hfe's of old transistors may vary quite a bit. I've found that more modern transistors like 2N5088 or 2n5089, BC549, BC550B or C, BC184's, 2N3904 don't vary so much and are more dependable. Old ones are sometimes quiet, sometimes noisy.

Thanks, @Iago, that's very helpful!

 

[caiofilipini]

Quick update here although I'm not done yet: got the BC108Bs, BC183s and 2N3700s today. Tested a bunch of them. They all sounded better than the other options I had before, to my ears at least. Really digging the BC183s!

I'll post some clips when I get a chance.

 

[Coda]

For stability, reliability, and availability, I Am really starting to appreciate 2N5088...

 

[caiofilipini]

I'll get some whenever I need more parts, thanks @Coda!

 

[Untro]

Hey all im pretty new and i really want to learn how different transistors sound so i can start understanding what related variables in a circuit effect sound and gain. Whats a good pedal to build to have some fun with transistor sockets? I have a Sabbath pcb i havent started, a rat problem and a few misc OD. Do you audition in a test box, or just fiddle with it after mounting in enclosure? Anything i should keep in mind before i blow out any ICs?
thanks in advance.

 

[music6000]

Good point. It's a Sunflower (Fuzz Face) in this case.

The Sunflower is designed for Germanium PNP Transistors using a Polarity Inverter so standard power supply & daisy chain can be used!

The Silicon version has some different values in it.

 

[Chuck D. Bones]

The Tone Benders are very sensitive to the transistor parameters, particularly the last transistor. Check out the Soul Vendor, Gnat & Scythe. Also, take a look at the Percolation Station.

Then there are the JFET pedals...
SOB
Corduroy
SOFTii
Covert
Deofol
M800
and so on...

Installing sockets on the board is the safest and easiest way to audition transistors.

 

[music6000]

Hey all im pretty new and i really want to learn how different transistors sound so i can start understanding what related variables in a circuit effect sound and gain. Whats a good pedal to build to have some fun with transistor sockets? I have a Sabbath pcb i havent started, a rat problem and a few misc OD. Do you audition in a test box, or just fiddle with it after mounting in enclosure? Anything i should keep in mind before i blow out any ICs?
thanks in advance.

With any Transistor other than recommended in the Build sheet, Make sure your check the Pinout, others will work but you might have to flip them 180 degrees.
Always look up the datasheet to see if the hFE is in the same region as the one your trying to replace if recommended Build is unavailable.
If you want more Gain (Higher hFe) or less Gain then look for the apprpiate transistor.

With the Sabbath, Build with PN4393 or MPF4393 only, save youself some heartache!
Mouser # 610-PN4393