Dunlop - Eric Johnson Signature Fuzz Face EJF1  [traced]

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Chris Brown
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Post by Chris Brown »

Mouseydung wrote:
Chris Brown wrote:Also early on we figured out that 330E is too low for most of us... I ended up with somewhere around 500... other people went as high as 680 I believe.
What is this "330E" you're referring to? I've done a search and couldn't find anything.
Sorry I'm in the habit of say E instead of ohm... mouser uses E instead of O or Ohms on their resistor packaging.

If you up the 330 ohm resistor to somewhere between 470 and 680 ohms you will get a lot more output

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Post by Chris Brown »

Mouseydung wrote:My current BC183s aren't really right for this project, so I'm waiting for the delivery of some new batches (darn, I wrote "bitches" by accident! :hmmm: ), hopefully sometime this coming week.
:horsey:
My experience was that the wrong gain bc183 sounded more "right" than the right gains of other transistors.

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Post by Mouseydung »

New batch of 100 BC183s arrived today. Nothing close to the magical 217 :cry: Waaaah!
"If it wasn't for bad luck, I wouldn't have no luck at all"
Incidentally, they're all B-C-E pin configurations.
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IMG_5255 mod.JPG

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Post by DrNomis »

Mouseydung wrote:New batch of 100 BC183s arrived today. Nothing close to the magical 217 :cry: Waaaah!
"If it wasn't for bad luck, I wouldn't have no luck at all"
Incidentally, they're all B-C-E pin configurations.


You could try just using the highest gain BC183 for Q2 and your lowest gain BC183 for Q1 and see what results you get with that combination....... :thumbsup
Genius is not all about 99% perspiration, and 1% inspiration - sometimes the solution is staring you right in the face.-Frequencycentral.

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Post by Mouseydung »

Mouseydung wrote:Incidentally, they're all B-C-E pin configurations.
OOOOooops! I meant to say they're all C-B-E configurations! :mrgreen:

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Post by Mouseydung »

SUCCESS!! :horsey:

I just received another batch of BC183s and found two with hFEs of 218 and 549. I put them into my build, adjusted the trim that feeds Q2 to about 8.66 K Ohms, at which point the transistor voltages were as follows:
Q1:
C: 1.27
B: 0.59
E: 0.0
Q2:
C: 3.18
B: 1.27
E: 0.68

Voila! I now have a super fuzz pedal now with cello/violin tones that is highly responsive to my playing and to tweaks of the volume and tone knobs on my guitar.

Turning the fuzz knob down no longer causes gating or sputtering. Before, with the hFE values of both transistors between 480 to 500, the fuzz knob was like an off switch when I turned to 50% or below. None of that is happening anymore -- I can now turn it all the way down and it still works!

I think I'm gonna like this pedal a lot!

Thanks so much guys, for your support. It's been an adventure and I've learned a heck of a lot from y'all. :D :popcorn:

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Post by DrNomis »

Mouseydung wrote:SUCCESS!! :horsey:

I just received another batch of BC183s and found two with hFEs of 218 and 549. I put them into my build, adjusted the trim that feeds Q2 to about 8.66 K Ohms, at which point the transistor voltages were as follows:
Q1:
C: 1.27
B: 0.59
E: 0.0
Q2:
C: 3.18
B: 1.27
E: 0.68

Voila! I now have a super fuzz pedal now with cello/violin tones that is highly responsive to my playing and to tweaks of the volume and tone knobs on my guitar.

Turning the fuzz knob down no longer causes gating or sputtering. Before, with the hFE values of both transistors between 480 to 500, the fuzz knob was like an off switch when I turned to 50% or below. None of that is happening anymore -- I can now turn it all the way down and it still works!

I think I'm gonna like this pedal a lot!

Thanks so much guys, for your support. It's been an adventure and I've learned a heck of a lot from y'all. :D :popcorn:



Just been working on my build, tried setting the trimpot to 8.66k as per your post, i found one transistor which had an Hfe reading of 549 so i used it for Q2, i had trouble finding a transistor that had an Hfe reading of 218 so I ended up using one that gave an Hfe reading of 310 for Q1, when i measured the voltages most of them were very close to what you have listed except for Q2's collector voltage, I measured 4.0 V, next I tried using the trimpot to adjust the 4.0v back to 3.18V, the other voltages measured exactly like yours so I tried my build out to see what it sounded like, it sounded more like Eric Johnson's signature Fuzz face, going to keep working on my build till I nail it....... :thumbsup
Genius is not all about 99% perspiration, and 1% inspiration - sometimes the solution is staring you right in the face.-Frequencycentral.

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Post by Mouseydung »

DrNomis wrote:Just been working on my build, tried setting the trimpot to 8.66k as per your post, i found one transistor which had an Hfe reading of 549 so i used it for Q2, i had trouble finding a transistor that had an Hfe reading of 218 so I ended up using one that gave an Hfe reading of 310 for Q1, when i measured the voltages most of them were very close to what you have listed except for Q2's collector voltage, I measured 4.0 V, next I tried using the trimpot to adjust the 4.0v back to 3.18V, the other voltages measured exactly like yours so I tried my build out to see what it sounded like, it sounded more like Eric Johnson's signature Fuzz face, going to keep working on my build till I nail it....... :thumbsup
I tried to get as close to the original traced values as possible. I've put the traced values in parentheses below, for comparison with mine.
Q1:
hFE: 218 (217)
C: 1.27 v (1.26)
B: 0.59 v (0.56)
E: 0.0 v (0.0)
Q2:
hFE: 549 (547)
C: 3.18 v (3.19)
B: 1.27 v (1.26)
E: 0.68 v (0.68)
I think there is most definitely something about the sound of BC183a they produce. It's more musical to my ears. I've tried putting some different transistors in that had somewhat close hFE values, but the sound just wasn't the same. Chris Brown wrote:
Chris Brown wrote:My experience was that the wrong gain bc183 sounded more "right" than the right gains of other transistors.

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Post by DrNomis »

Mouseydung wrote:
DrNomis wrote:Just been working on my build, tried setting the trimpot to 8.66k as per your post, i found one transistor which had an Hfe reading of 549 so i used it for Q2, i had trouble finding a transistor that had an Hfe reading of 218 so I ended up using one that gave an Hfe reading of 310 for Q1, when i measured the voltages most of them were very close to what you have listed except for Q2's collector voltage, I measured 4.0 V, next I tried using the trimpot to adjust the 4.0v back to 3.18V, the other voltages measured exactly like yours so I tried my build out to see what it sounded like, it sounded more like Eric Johnson's signature Fuzz face, going to keep working on my build till I nail it....... :thumbsup
I tried to get as close to the original traced values as possible. I've put the traced values in parentheses below, for comparison with mine.
Q1:
hFE: 218 (217)
C: 1.27 v (1.26)
B: 0.59 v (0.56)
E: 0.0 v (0.0)
Q2:
hFE: 549 (547)
C: 3.18 v (3.19)
B: 1.27 v (1.26)
E: 0.68 v (0.68)
I think there is most definitely something about the sound of BC183a they produce. It's more musical to my ears. I've tried putting some different transistors in that had somewhat close hFE values, but the sound just wasn't the same. Chris Brown wrote:
Chris Brown wrote:My experience was that the wrong gain bc183 sounded more "right" than the right gains of other transistors.


I was having a bit of a think to myself and I'm thinking that maybe the reason why I've been finding it hard to gey my build sounding right is that I've been going about it the wrong way, before I'd put the two transistors in their sockets and then adjust the trimpot for the right Q2 collector voltage, it always ended up with my build not having alot of output level, I tried it the way you described and the results were alot better..... :thumbsup


I'll have to see if I can buy some more BC183 transistors on eBay soon..... :thumbsup
Genius is not all about 99% perspiration, and 1% inspiration - sometimes the solution is staring you right in the face.-Frequencycentral.

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Post by Chris Brown »

Mouseydung wrote:SUCCESS!! :horsey:
Congratulations! I knew you'd end up with a killer fuzz. The initial build is only half of the equation with these things... swapping parts until it's perfect is how beauty emerges.

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Post by Skreddy »

...so I checked a few transistors in the big bag of BC183's on which I had previously written "<300 hfe". I don't know how that got on there; these things are all in the high 700's! Oh well. :scratch: Sorry for the false alarm.

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Post by Chris Brown »

Skreddy wrote:...so I checked a few transistors in the big bag of BC183's on which I had previously written "<300 hfe". I don't know how that got on there; these things are all in the high 700's! Oh well. :scratch: Sorry for the false alarm.
bc183 can sometimes be temperature sensitive... usually not that much though... did you test them in a blizzard and then again in the desert perhaps? :block:

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Post by Mouseydung »

If I were to mount a LED indicator directly onto the PCB and not via the 3PDT footswitch, where is a good place for this to go so that it'll turn on like it should only when the pedal is engaged?

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Post by Chris Brown »

Mouseydung wrote:If I were to mount a LED indicator directly onto the PCB and not via the 3PDT footswitch, where is a good place for this to go so that it'll turn on like it should only when the pedal is engaged?
It really doesn't work that way... you are going to need a 3PDT.

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Post by Mouseydung »

Chris Brown wrote:It really doesn't work that way... you are going to need a 3PDT.
Hmm.. I've seen a coupla fuzz kits and many other pedals where the LED goes directly onto the PCB and it turns on only when the pedal is engaged. Perhaps one of the wires from the 3PDT to the PCB goes directly to the current-limiting resistor + LED anyway, and the 9V+ is channeled to the LED and then to the ground, but it's all done neatly on the PCB.

Check this out: http://moodysounds.com/download/moody%2 ... matics.pdf

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Post by modman »

Mouseydung wrote:
Chris Brown wrote:It really doesn't work that way... you are going to need a 3PDT.
Hmm.. I've seen a coupla fuzz kits and many other pedals where the LED goes directly onto the PCB and it turns on only when the pedal is engaged. Perhaps one of the wires from the 3PDT to the PCB goes directly to the current-limiting resistor + LED anyway, and the 9V+ is channeled to the LED and then to the ground, but it's all done neatly on the PCB.
Check this out: http://moodysounds.com/download/moody%2 ... matics.pdf
Thanks for contributing your voltages and taking time to fussy about transistors. But this thread is already 20 pages...
Switch-wiring questions are answered here:
Switchin & Wiring FAQ
and what you'll need here is this:
http://fuzzcentral.ssguitar.com/faq/switchwiringnpn.gif
if the transistor is npn

If the led is board mounted, it is wiring back to the switch...
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

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Post by Mouseydung »

modman wrote:Thanks for contributing your voltages and taking time to fussy about transistors. But this thread is already 20 pages...
Gotcha! I copied the links you shared in answer to my question. Please delete all my posts from today!

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Post by polifemo »

Skreddy wrote: BC109's are very full and open; just need to tweak the resistors and caps to dial in the right balance and touch; with the right bias, they almost sound "clean" when in full fuzz mode.
What do you consider "the right bias" to be for a pair of BC109s in order to obtain this "clean fuzz tone"?
(Tried your BC109 Fuzz today and really liked the tone!)

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Post by jalmonsalmon »

polifemo wrote:
Skreddy wrote: BC109's are very full and open; just need to tweak the resistors and caps to dial in the right balance and touch; with the right bias, they almost sound "clean" when in full fuzz mode.
What do you consider "the right bias" to be for a pair of BC109s in order to obtain this "clean fuzz tone"?
(Tried your BC109 Fuzz today and really liked the tone!)
+1
BC109 fuzz is awesome :thumbsup

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Post by Skreddy »

I use the standard 33k emitter resistor for Q1
Q2's bias is set thusly: an 820R to 9v, which is where I tap the output signal to the volume pot (and I use a .047uf cap to make a 100k pot sound the same as a .01 cap into a 500k pot) and a 1.8k resistor in series with a 10k bias pot.

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