# Fuchsia Fuzz Transistor set advice



## cooder (Feb 13, 2020)

Howdy, I have a Fuchsia Fuzz in the works and wonder if you guys and gals can help me with some advice on what trannies to use.
I have a PN 4393 will that work equivalent to the MBF4393 specified on build doc?
Also: I do have BC550B and I think the BC550C specifiesd would have slightly higher gain on average, I think that's what the 'C'suffix stand for (correct me if I'm wrong, cheers). Will the BC550B still do the job, should I try to measure through a bunch to catch the highest gain or will it not make a difference in the circuit?
Also, last not least, where would I get a 2N1308 trannie or equivalent from, what's the recommended gain there and can I substitute other NPN Ge transistors?

Cheers for any advice!


----------



## cooder (Feb 16, 2020)

Bump.... anyone experience or ideas with this circuit? Cheers!


----------



## Nostradoomus (Feb 16, 2020)

You can always sub for different NPN GE transistors, all you have to watch out for is the pin out. Some circuits are sensitive to the leakage and hfe rating, it’s best practice to just socket it and try a whole mess of different ones til something really pops out.

PN4393 is the same as MPF4393, different manufacturer.

You’re correct about the B/C suffix, C will be the higher gain. Try a 2n5088 or MPSA18 if you have them. 2n5088 is my go to replacement for most transistors.


----------



## cooder (Feb 16, 2020)

Nostradoomus said:


> You can always sub for different NPN GE transistors, all you have to watch out for is the pin out. Some circuits are sensitive to the leakage and hfe rating, it’s best practice to just socket it and try a whole mess of different ones til something really pops out.
> 
> PN4393 is the same as MPF4393, different manufacturer.
> 
> You’re correct about the B/C suffix, C will be the higher gain. Try a 2n5088 or MPSA18 if you have them. 2n5088 is my go to replacement for most transistors.


Awesome thanks! I thought that the PN4393 was the same diff manufacturer/labelling, thanks for confirming. I'' do the NPN socketing and see how I go and I'll see with the BC550 I measured a batch and picked the slightly higher gain ones. Will compare with the 2N5088 recommendation, good one! Cheers!


----------



## Chuck D. Bones (Feb 17, 2020)

What Nostradoomus said!  Check the JFET drain voltage.  As long as it's between 5V and 7V, you're good.  The circuit is pretty forgiving of variations in the Si and Ge transistors.  Small Bear sells 2N1306's, that's what I put in mine.  AC127 is another good choice.  Russian Ge transistors will work, as long as they are not too leaky.  The collector voltage on mine is 2.0V, I would not go any lower than that.  My favorite fuzz.


----------



## cooder (Feb 21, 2020)

Chuck D. Bones said:


> What Nostradoomus said!  Check the JFET drain voltage.  As long as it's between 5V and 7V, you're good.  The circuit is pretty forgiving of variations in the Si and Ge transistors.  Small Bear sells 2N1306's, that's what I put in mine.  AC127 is another good choice.  Russian Ge transistors will work, as long as they are not too leaky.  The collector voltage on mine is 2.0V, I would not go any lower than that.  My favorite fuzz.


Awesome, thanks for the info! That'll help a great deal!


----------

