Who's played with different transistors in the SHO?

Frequently asked question on transistors: types, substitutions, how to test, use and misuse them.
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wesc
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Post by wesc »

I had a few misc transistors lying around and I just finished another SHO w/ added volume and tone controls (here's another question, the tone control sucks. I am using a 47uf cap for it and I much prefer this circuit without any tone knob. Has anyone put a good tone circuit to roll of a bit of high end for certain applications?). I socketed the transistor this time, so I tried swapping it with what I had lying around. I honestly didnt research to see if the pinouts were right or anything because I really didnt care if these transistors got fried. The stock BS170 is great, but I think I found a better one with more gain on tap. First I tried and MPF102 which had less gain (this is a JFET right? Those have less gain right?). Then I tried one that says C549C on it and this this sound much better with this. It appears to be a low voltage mosfet after looking up the datasheet. Has anyone else found any other good matches for this circuit? I kind of want to make a breadboard of this with tons of different transistors and maybe try different diodes. Any suggestions? These SHO pedals with the master volume are seriously the greatest OD pedals Ive ever played because of the transparency and dynamics.

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Drzeus
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Post by Drzeus »

Bs170's were used by zvex in the start,tho 2n7000's work well.Any n-channel mosfet should be ok?Best to have a terminal,and get a few likely suspects,and see how they sound?
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wesc
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Post by wesc »

Do the 2n7000s sound similar or more or less gain. The c457c I tried has about twice the amount of gain as the original.

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Drzeus
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Post by Drzeus »

IMHO,the bs170 has a little more gain,and is a little 'rougher'?
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Zokk
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Post by Zokk »

I've tried regular BS170s and one BS170P from Zetex (pretty expensive), and even if it's really subjective I prefered the "P" version but it has very little differences from the regular BS170 which don't justify the price I think; maybe a bit more gain and a bit cleaner when the pot is at max setting... and different pinout of course!
So if I build another one I will stuck on the regulars and save my money.

Anyway I think I've made a good upgrade in my SHO while using a big 100V 10uF wima like cap instead of the electro, that's way better with this cap but it's huge.
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SHO, zener version
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Seiche
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Post by Seiche »

in my build i found the 2n7000 that I tried a little grittier, than the BS170 that seemed cleaner. I tried a BS170p and they all basically sound the same with marginal difference. But of course BS170 are all supposed to sound different from each other, so those differences between different kinds of transistors might be less than the actual tolerances when using the same kind of transistor.

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