Hi all,
I recently started with my first DIY guitar effect: a fuzz face. I got the parts from a local electronics store, they did not have the preferred transistors for the fuzz face, so I took the only germanium transistors he got: AC187K.
The fuzz works, but to my opinion, not enough
The lower notes don't have much fuzz (olmost nothing). Also, when I play single notes (just 1 string), there is not much fuzz, even on the higher strings. When I play 2 strings together, there is much more fuzz, but again, only at the higher notes, not at the lower notes.
The guy from the store was saying something about these transistors beiing used for high frequencies. could it be that the lower frequencies are filtered out? According to the datasheet: fab MHZ Min = 1. Is this the minimal frequency for the transistor to work?
If this is true, it could explain why is't behaving like this. I can imagine that, when playing 2 strings at the same time, the output signal of the guitar is much more distorted, having much higher frequencies. Only at this point the fuzz would sound fully... Does anyone agree?
In the meanwhile, i'm looking for the right transistors, just trying to explain this strange behaviour
If anyone has advice, thanks!
Thomas
I recently started with my first DIY guitar effect: a fuzz face. I got the parts from a local electronics store, they did not have the preferred transistors for the fuzz face, so I took the only germanium transistors he got: AC187K.
The fuzz works, but to my opinion, not enough
The lower notes don't have much fuzz (olmost nothing). Also, when I play single notes (just 1 string), there is not much fuzz, even on the higher strings. When I play 2 strings together, there is much more fuzz, but again, only at the higher notes, not at the lower notes. The guy from the store was saying something about these transistors beiing used for high frequencies. could it be that the lower frequencies are filtered out? According to the datasheet: fab MHZ Min = 1. Is this the minimal frequency for the transistor to work?
If this is true, it could explain why is't behaving like this. I can imagine that, when playing 2 strings at the same time, the output signal of the guitar is much more distorted, having much higher frequencies. Only at this point the fuzz would sound fully... Does anyone agree?
In the meanwhile, i'm looking for the right transistors, just trying to explain this strange behaviour
If anyone has advice, thanks!
Thomas
Hi,
Th fuzz face is a very simple circuit. It's performance depends heavely on the few components it uses.. get some bc109 and build it again.. check the Hfe (current gain) of the transistor.. higher Hfe will give more fuzz..
Could you post a schematic of the circuit as you build it ?
grtz, Thijs
Th fuzz face is a very simple circuit. It's performance depends heavely on the few components it uses.. get some bc109 and build it again.. check the Hfe (current gain) of the transistor.. higher Hfe will give more fuzz..
Could you post a schematic of the circuit as you build it ?
grtz, Thijs
http://www.geofex.com/article_folders/fuzzface/fftech.htm
I looked at the data for the AC187K, it's an NPN with an hfe of 100-500, so not the end of the world, keep going.
tschrama, telling someone who put the effort into finding germanium transistors to quit and use silicon is like telling someone with a flat on their Ferrari to buy a Fiat.
I looked at the data for the AC187K, it's an NPN with an hfe of 100-500, so not the end of the world, keep going.
tschrama, telling someone who put the effort into finding germanium transistors to quit and use silicon is like telling someone with a flat on their Ferrari to buy a Fiat.
hehehe
but hee he seems to be a newbie with this stuff , so I was trying first to get him around the circuit in a Fiat..
He can always upgrade to a Ferrari later..
PS
the current ' Jimi hendrix Fuzz Face' is build around the BC109 .. that's why I came up with that particular type..
PPS
great link!
PPS nope.. not BC109 but BC108..see http://nl.youtube.com/watch?v=0EqrQPbOhDo
but hee he seems to be a newbie with this stuff , so I was trying first to get him around the circuit in a Fiat..
He can always upgrade to a Ferrari later..
PS
the current ' Jimi hendrix Fuzz Face' is build around the BC109 .. that's why I came up with that particular type..
PPS
great link!
PPS nope.. not BC109 but BC108..see http://nl.youtube.com/watch?v=0EqrQPbOhDo
Didn't the original Fuzz Face use a PNP germanium?
I'm planning to build a Fuzz Face clone myself, and picked up some GT308V PNP Germanium's off of Ebay for a very reasonable price ($20/50) They have very low leakage and had hfe's of 55-90 so should be good for the Fuzz Face circuit.
Another good site is:
http://fuzzcentral.ssguitar.com/fuzzface.php
- Gary
I'm planning to build a Fuzz Face clone myself, and picked up some GT308V PNP Germanium's off of Ebay for a very reasonable price ($20/50) They have very low leakage and had hfe's of 55-90 so should be good for the Fuzz Face circuit.
Another good site is:
http://fuzzcentral.ssguitar.com/fuzzface.php
- Gary
Might want to build this if more fuzz needed
just finished this diy fuzz factory in arion enclosure but with a difference to original
http://uk.youtube.com/watch?v=hr99z456exA
just finished this diy fuzz factory in arion enclosure but with a difference to original
http://uk.youtube.com/watch?v=hr99z456exA
If this is your first project, I recommend buying a pair of matched transistors from Small Bear and building the circuit with quality trimpots for all the resistors. That way you can the resistors in the circuit to the values supplied with the transistor pair so that they will be biased properly. I also recommend using a 1k linear pot in place of the 8k2 bias resistor so that you can tweak its value to compensate for different operating temperatures or just to get different sounds.
The first fuzz face I built was a stock circuit with transistors measuring around 95 (q1) and 140 (q2) hfe, and it sounds good, produces more fuzz than a tweaked circuit at the expense of cleaning up less as the guitar volume is rolled back.
The first fuzz face I built was a stock circuit with transistors measuring around 95 (q1) and 140 (q2) hfe, and it sounds good, produces more fuzz than a tweaked circuit at the expense of cleaning up less as the guitar volume is rolled back.
ThomasDIY said:
The fuzz works, but to my opinion, not enough
I doubt that the transistor itself has anything to do with what you are experiencing.
First, you need more gain. That can be achieved by using a higher hfe transistor, but any means of pre-fuzz amplification will do.
Second, it's a common practice to put an EQ pre and post fuzz, so that you can shape your signal. In this case you would boost bass a bit in the pre-fuzz EQ so that lower frequencies would clip earlier and therefore buzz more.
If you use a booster circuit between the fuzz circuit and the guitar, it will make the fuzz circuit respond a lot differently than if it were connected directly to the guitar, though (it would sound more like a high gain distortiong such as a Big Muff than like the classic Fuzz Face sound). I'd recommend getting higher gain transistors myself. The hfe 90 one should be perfect for Q1, so you really only need a single transistor with an hfe between maybe 95 and 115 for Q2. You can use the lower gain one that you already have in a Dallas Rangemaster clone (which is a really nice pedal to have around) or similar.
new fuzz face not working
I also recently built a fuzz face using the original schematic except with an led and transistors from small bear. it works in bypass, and when i engage it, the led comes on, but there is no sound. Also, I tested every connection with an ohmmeter and used an audio probe to try to see where the sound was stopping, but it didn't even work when I just connected it to the input jack. it worked when i did that in bypass, but not when it was engaged. does anyone have any tips?
I also recently built a fuzz face using the original schematic except with an led and transistors from small bear. it works in bypass, and when i engage it, the led comes on, but there is no sound. Also, I tested every connection with an ohmmeter and used an audio probe to try to see where the sound was stopping, but it didn't even work when I just connected it to the input jack. it worked when i did that in bypass, but not when it was engaged. does anyone have any tips?
Hi there!
although I do not disregard what the others have said, and while I am not an expert on the subject, I would suggest that you change the value of the second transistor's emitter capacitor, the one that is on the wiper of the fuzz control. You need to make it bigger. I believe the original value is 22uF, is it not? Make it 33uF. also make the input capacitor bigger, say, 4,7uF.
this is why your high frequencies are more distorted: the impedance of a smaller value cap is higher at low frequencies than a bigger value cap. the secret is to play with these values. But if you do change the transistors, you might end up with overall higher gain which will do the same.. but my suggestion is simpler.
Also, like another user said, this effect is sensitive to pickup variations, if you have weak pickups, it will not distort as much. This is probably why he suggested using a preamp.
As for me...
My fuzz face replica works just fine and dandy with Vintage TI 2N291 transistors and old electrolytic capacitors scrounged off an old reel to reel tape deck. I followed the basic schematic on the Geofex website.
Mind you I never heard a real vintage Dunlop fuzz face, straight into an amp.
but,
I'm telling you people, nothing beats vintage parts.
although I do not disregard what the others have said, and while I am not an expert on the subject, I would suggest that you change the value of the second transistor's emitter capacitor, the one that is on the wiper of the fuzz control. You need to make it bigger. I believe the original value is 22uF, is it not? Make it 33uF. also make the input capacitor bigger, say, 4,7uF.
this is why your high frequencies are more distorted: the impedance of a smaller value cap is higher at low frequencies than a bigger value cap. the secret is to play with these values. But if you do change the transistors, you might end up with overall higher gain which will do the same.. but my suggestion is simpler.
Also, like another user said, this effect is sensitive to pickup variations, if you have weak pickups, it will not distort as much. This is probably why he suggested using a preamp.
As for me...
My fuzz face replica works just fine and dandy with Vintage TI 2N291 transistors and old electrolytic capacitors scrounged off an old reel to reel tape deck. I followed the basic schematic on the Geofex website.
Mind you I never heard a real vintage Dunlop fuzz face, straight into an amp.
but,
I'm telling you people, nothing beats vintage parts.
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