spacecadetcharlie
New member
Here's some info on my ReproFuzz build... I've made one pedal before this but have knowledge from modifying guitar amps and repairing home hifi amps, so not a total stranger to components and builds.
TL;DR: Mods -
R1 2k4 ohm (original 3k3)
R10 22k ohm (original 4k7)
Bass pot A200k (original B250k)
At first I built this to spec. It sounded "okay." Another thread here (by HamishR) quotes:
Agreed 100%. This thing also has an absurd amount of bass... anything about 9 o'clock is too much in my rig. So, no mids, too much bass, highs that are both veiled and extended.
I was already well aware of the Fender tone stack this thing uses. A while back I added a mid control to my Princeton. But I also read through the excellent Chuck D. Bones analysis... well worth multiple reads it if you are looking at this pedal.
I suspected that the blanketed quality of this pedal was the mid scoop. It's not an exact replica Fender tone stack; some of the cap and resistor values have been changed (in my humble opinion to its detriment). As many have noted, the mid scoop is higher and deeper in this iteration, and to my ear not enjoyable. However, I tweaked, swapped resistors here and there, pulled parts, etc. and ended up with this result, which I think makes this pedal excellent and musical in a wide variety of configurations.
The first thing I wanted to do was tackle the mid scoop. There are many ways to do this, but I knew from my Princeton that adding an A25k variable resistor pot as a mid control is a common mod (sometimes called a Nashville mod). I swapped R10 (4k7) to a 10k. It sounded better with treble and bass at 0, but I still felt there was too much scoop and that the treble and bass pots weren't useable. I put a 22k in and voila. It brought the mids up to a point where the treble and bass pots had musical range.
The second thing I did was tackle the touchy bass pot. This would be easier solved by using an A200k pot, but I had already ordered a B250k pot, so I improvised. I soldered a 220k resistor across 1 and 3, making the total resistance of the pot ~111k. The control of the B taper bass pot is still touchy but much less absurd now. However, if ordering fresh supplies, I would use an A200k pot here just to have the smoother control of the A taper.
The last thing I tried was messing around with the input resistor, R1. I wasn't entirely sure what this would do, although I understand the most basic fundamentals of impedance. I noticed that original fuzz faces don't have this resistor... instead, the input goes straight to a capacitor and into the first transistor. However, a common mod for Fuzz Face pedals is called the Fuller mod (via Mike Fuller), which adds a 50k variable resistor pot in front of this capacitor in the originals... this is a good explanation of this circuit and the mods.
So first, I tried R1 bypassed (a la the original Fuzz Face) and noticed a thicker, wetter, heavier fuzz, with a touch more mids and low mids than the stock 3k3. Then, I went the other way, and put a 10k in R1, and noticed the fuzz got more brittle, scratchy, and fizzy, but I lost the bottom end I had carefully tailored with my tone stack mods. Both of these sounded good, so I think it could be up to personal taste. Ultimately, I went with a 2k4 in R1, which warmed the whole presentation just a touch.
Having done these mods, this pedal went from a giveaway to something that's going to be on my board for good. I really like this pedal! And I'm sure my next build will be a bit cleaner, too.
TL;DR: Mods -
R1 2k4 ohm (original 3k3)
R10 22k ohm (original 4k7)
Bass pot A200k (original B250k)
At first I built this to spec. It sounded "okay." Another thread here (by HamishR) quotes:
Agreed 100%. This thing also has an absurd amount of bass... anything about 9 o'clock is too much in my rig. So, no mids, too much bass, highs that are both veiled and extended.
I was already well aware of the Fender tone stack this thing uses. A while back I added a mid control to my Princeton. But I also read through the excellent Chuck D. Bones analysis... well worth multiple reads it if you are looking at this pedal.
I suspected that the blanketed quality of this pedal was the mid scoop. It's not an exact replica Fender tone stack; some of the cap and resistor values have been changed (in my humble opinion to its detriment). As many have noted, the mid scoop is higher and deeper in this iteration, and to my ear not enjoyable. However, I tweaked, swapped resistors here and there, pulled parts, etc. and ended up with this result, which I think makes this pedal excellent and musical in a wide variety of configurations.
The first thing I wanted to do was tackle the mid scoop. There are many ways to do this, but I knew from my Princeton that adding an A25k variable resistor pot as a mid control is a common mod (sometimes called a Nashville mod). I swapped R10 (4k7) to a 10k. It sounded better with treble and bass at 0, but I still felt there was too much scoop and that the treble and bass pots weren't useable. I put a 22k in and voila. It brought the mids up to a point where the treble and bass pots had musical range.
The second thing I did was tackle the touchy bass pot. This would be easier solved by using an A200k pot, but I had already ordered a B250k pot, so I improvised. I soldered a 220k resistor across 1 and 3, making the total resistance of the pot ~111k. The control of the B taper bass pot is still touchy but much less absurd now. However, if ordering fresh supplies, I would use an A200k pot here just to have the smoother control of the A taper.
The last thing I tried was messing around with the input resistor, R1. I wasn't entirely sure what this would do, although I understand the most basic fundamentals of impedance. I noticed that original fuzz faces don't have this resistor... instead, the input goes straight to a capacitor and into the first transistor. However, a common mod for Fuzz Face pedals is called the Fuller mod (via Mike Fuller), which adds a 50k variable resistor pot in front of this capacitor in the originals... this is a good explanation of this circuit and the mods.
So first, I tried R1 bypassed (a la the original Fuzz Face) and noticed a thicker, wetter, heavier fuzz, with a touch more mids and low mids than the stock 3k3. Then, I went the other way, and put a 10k in R1, and noticed the fuzz got more brittle, scratchy, and fizzy, but I lost the bottom end I had carefully tailored with my tone stack mods. Both of these sounded good, so I think it could be up to personal taste. Ultimately, I went with a 2k4 in R1, which warmed the whole presentation just a touch.
Having done these mods, this pedal went from a giveaway to something that's going to be on my board for good. I really like this pedal! And I'm sure my next build will be a bit cleaner, too.
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