Matching silicon transistors for FF & TB clones

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

Dear Friends

I know a lot about matching germanium transistors thanks to posts over FSB and great R.G's article, but is there any rule of matching SILICON ones? What hfe range is right for maximum performance of silicon FuzzFace, and Tone Benders?

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Pawel

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Post by sinner »

One more thing, because there was no much responses to my questions in past, I will give a flower to first person who will answer my question ;) [smilie=a_sunflower.gif] [smilie=a_jester.gif]

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Post by KTB »

http://www.geofex.com/Article_Folders/ffselect.htm

Did you not believe RG ? :)
I get the matched pairs from small bear and they work great but I guess one day they will run out. Sometimes a little different hfe's give a sweeter harmonic content instead of just exact matches which is also stated in RG's text.

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Post by sinner »

KTB wrote:http://www.geofex.com/Article_Folders/ffselect.htm

Did you not believe RG ? :)
I get the matched pairs from small bear and they work great but I guess one day they will run out. Sometimes a little different hfe's give a sweeter harmonic content instead of just exact matches which is also stated in RG's text.
Dude, no flower for you sadly :( I'm asking about silicon transistors, and R.G. is writing about germaniums :) And yes, I believe in what he's saying :)

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Post by Nilvert »

Both are BJT's, they do the same thing so can be tested via the same method.

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Post by KTB »

http://acapella.harmony-central.com/arc ... 39788.html

:oops: Sure isn't my day.
They are different materials of course but both bjt and I can say the 2n3904's were not as good as the germaniums so must be some mojo there. I think I used some can type silicons that sounded much better than the TO-92 package type.

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Post by sinner »

Nilvert wrote:Both are BJT's, they do the same thing so can be tested via the same method.
dude

http://www.datasheetcatalog.org/datashe ... _109_4.pdf

as you see hfe of silicon BC108 is between 110-800 hfe, as an example NKT275 is 40-100hfe in data sheet, typical FF gain range should be 60-80hfe for Q1 and 100-120hfe for Q2, so my question is what hfe range of silicon is best for fuzz face and tone benders... I can't make it more clear :oops:

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Post by Jarno »

I did both a germanium and silicon muff a couple of weeks ago, and I checked the Hfe of a handful of silicon transistors to pick out the most suitable ones. Pointless exercise, I tested about 3 types (probably BC547, BC560, and 2N3904), and they were all about +/-5 to 10 Hfe in their respective group. Not nearly as much variation as ge transistors. The ones I bought have real gains that vary from about 95 to 260, all with low, but varying, leakage.

I don't think the Hfe range differs from ge to si, it's a matter of tweaking it to the sound you like. But if you would like to use slightly lower for the first one and somewhat higher for the second, I think your better off choosing two different types of BJT than buying a whole batch of a single type and sorting them.

And yes, the Hfe's mentioned in the datasheet vary by quite a bit, but the actual parts are quite close (at least in my experience).
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Post by Nilvert »

sinner wrote:
Nilvert wrote:Both are BJT's, they do the same thing so can be tested via the same method.
dude

http://www.datasheetcatalog.org/datashe ... _109_4.pdf

as you see hfe of silicon BC108 is between 110-800 hfe, as an example NKT275 is 40-100hfe in data sheet, typical FF gain range should be 60-80hfe for Q1 and 100-120hfe for Q2, so my question is what hfe range of silicon is best for fuzz face and tone benders... I can't make it more clear :oops:
the rules for matching them are the same, gain is measured with the same method, the rule for what sort of gain characteristics to use are determined by the rule of "this combination sounds best to me".

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Post by johnnyg »

In the npn si ff I made I tried out various low gain transistors. I bought quite a few as they're cheap enough and measured what I got with my multimeter - the types I found best are 2n222a; bc107a; 2n5551; 2369a. It's easy to find hfe in the range recommended for a ff with these types (and there are probably plenty more like these): something like c.100hfe for Q1 and 120-130 or a bit more for Q2... in fact, the 2369a was possibly too weak - some I have are around 40hfe (according to my cheapo multimeter). Remember the recommended gain for transistors in a fuzz face is just that: recommended. You should experiment a bit - maybe you like a weaker transistor in Q2 or a stronger one in Q1 etc. The good thing about silicon transistors is that they're cheap and plentiful - unlike Germanium!

Just buy a handful of such transistors, measure them, and try out the ones with the kind of hfe you're after - your ears will tell you what to pick. Think I went for a 2n222a in Q1 and a BC107a in Q2.

For a pnp circuit, I think you have less choice. I've recently got some with hfe <100 - 2n4125 - intend trying them in a TB MKII circuit. I've got a load of 2n3906 which measure below <200 - some as low as 130ish. But according to the datasheets it should be possible to get these at even lower gain.

Hope that helps a bit.
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Post by sinner »

Little late but huge thanks guys for all replays, specially for you Johnny. I know you like hybrid FF a lot, so maybe you, or others will recommend me silicon NPN for my SI/GE project?

I have few types, all are low gain:
- 2N2369
- 2N3440
- 2N5133

Any experience with the fallowing transistors?

This will works in pair with NPN CV7112 hfe approx 110
johnnyg wrote:Think I went for a 2n222a in Q1 and a BC107a in Q2.
2N222A maybe you mean 2N2222A? :)

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Post by mojoh »

excuese the noob question...but how do you actually measure the hfe (or whatever) for the transistors with a multimeter?
i have a nice fluke mm but no idea how to measure transistors.

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Post by sinner »

This is the thing I'm using, and I love it! must to have for germaniums http://www.peakelec.co.uk/acatalog/jz_dca55.html

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Post by johnnyg »

mojoh wrote:excuese the noob question...but how do you actually measure the hfe (or whatever) for the transistors with a multimeter?
i have a nice fluke mm but no idea how to measure transistors.
I've heard of Fluke, but never encountered one - on the multimeters I have you should either have a little transistor socket on the body of the meter or sometimes a separate socket that you connect to the leads from the meter. The socket will be labelled for npn and pnp with the letters 'cbe/ebc' perhaps. You may have to look for datasheets to determine the correct pin out of your transistors... or you could just stick them in one way then another to determine the pin out along with the gain/hfe,

That will work for silicon transistors. If you want to measure germanium ideally you will have the amazing Peak analyser like Sinner mentions. Otherwise look for Mr (or Miss/Mrs? :P ) RG Keen's Geofex article on the issue.
sinner wrote:Little late but huge thanks guys for all replays, specially for you Johnny. I know you like hybrid FF a lot, so maybe you, or others will recommend me silicon NPN for my SI/GE project?

I have few types, all are low gain:
- 2N2369
- 2N3440
- 2N5133

Any experience with the fallowing transistors?

This will works in pair with NPN CV7112 hfe approx 110
johnnyg wrote:Think I went for a 2n222a in Q1 and a BC107a in Q2.
2N222A maybe you mean 2N2222A? :)
Yeah 2n2222a - sorry! Too many twos involved (as in this sentence)!

I've tried out 2n2369 and, I'm pretty certain, 2n5133 as well... but since writing that post above I've decided my favourite npn si transistor is the BC108. I didn't mention it above as those I had at the time were all pretty high gain. Since then I've got some as low as 120ish. I need to make it clear that my experimenting and tinkering is very limited!!! :oops: Others on here will know better than me! Plenty of transistors sound ok or good - but to date, in the various yaffs I've built the BC108 always sounds great... as you might expect given that's the type used in the original si fuzz faces! So I'll be sticking with that from now one - with the massive gain range of them there's a bit of luck involved getting some in the range you're after (if you can find graded ones - a, b, c etc that helps).

You probably need to experiment yourself though matey! Can you build a FF with sockets separate from any fancier builds you plan on doing to test things out (if you don't want sockets in your better builds)?
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Post by IvIark »

Save those 2N5133s for a muff. They're the ones Skreddy used in the Pink Flesh and Mayo, and are pretty rare now.
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Post by KindaFuzzy »

In a tonebender I like the 2222's the best, somewhere between 100-200hfe for all sounds best to me, but I usually leave the fuzz knob on 10 all the time and play with a danelectro (super weak pickups). The 2369s are better in a fuzz face, the ones I have are around 60-100 hfe and again I like the higher gain ones in there. I did sub in a bunch of random salvaged transistors with lowish gains, and couldn't really tell a difference, they all sound good as long as they're not 5089s or something with tons of gain. Too much gain got kind of oversaturated sounding, but not in a nice big muff way.

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Post by sinner »

Thanks guys, I forgot that I have some 2n3440's AFAIR from you KF :D I need to check what is in my boxes often that I do :oops: :roll: They are in range of 77-82hfe, so it seems like perfect choice for SI/GE build. I'll let you know

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Post by KindaFuzzy »

I'll have to get a few more of those 3440s and try them too, I didn't realize they were low gain. The one tranny I do have measures 58hfe, which is probably a little too low for fuzz.

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Post by sinner »

KindaFuzzy wrote:I'll have to get a few more of those 3440s and try them too, I didn't realize they were low gain. The one tranny I do have measures 58hfe, which is probably a little too low for fuzz.

I tried to select the highest one, as the only germanium NPN trannie I have measures 153Hfe of gain and no leakage (whoohoo!!!), so this gonna be bad mother fucker...

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Post by KindaFuzzy »

Bitchin'

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