Gnat Fuzz sounds very gated

J

JFurgie

New member
I recently finished a build of the Gnat fuzz and I haven’t been able to get it to sustain or feedback in that classic Fripp style. The pedal seems to gate off my notes quite easily even when everything is cranked. Transistor hfe values are:
Q1 - 67
Q2 - 92
Q3 - 106
I know the recommended value on Q3 is around 120, could my problem just be a matter of replacing Q3 to a closer value? Or could this be another issue.
Appreciate any help on this
Thanks
 
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Buzzaround was not the only dirt pedal Robert Fripp used. I've heard rumors that he also used one of the Big Muffs. That would be consistent with some of the compressed, long sustaining, violin-like tones we hear on King Crimson, Eno & Bowie recordings.

As for the gating, It's all about the leakage in Q3. I built a similar circuit, a PNP version of the EQD Tone Reaper (Scythe). I put a low leakage transistor (2N1307) in the last stage (Q3 in the Gnat) and it was very gated and sputtery. I then switched to a Russian GT402B and it opened right up. The tone of this circuit is all about Q3. Try some different transistors there and you'll know when you have the right one.

Try this, measure the collector voltage on Q3 with the SUSTAIN & BALANCE turned all the way up. It should be around -1V or so. If it's close to -2V, then Q3 is not leaking enough current to bias itself on.
 
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Thanks so much for this great info! I’ve measured Q3’s collector to be at around -1.9V with balance and sustain at max so it would appear that is the culprit. I’ll try swapping this out for a higher leak transistor and update the results.
 
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Update:
I’ve got the pedal working beautifully. I shuffled around some different combos of transistors and settled on a combination I really dig. Getting about -0.9V on Q3 collector now. No more gating and much more sustain/feedback. Thanks again!
 
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Chuck D. Bones said:
Buzzaround was not the only dirt pedal Robert Fripp used. I've heard rumors that he also used one of the Big Muffs. That would be consistent with some of the compressed, long sustaining, violin-like tones we hear on King Crimson, Eno & Bowie recordings.
Click to expand...

Fripp: It really doesn't matter what kind of fuzz box you use. It has more to do with the state of mind.

But if somebody wanted to obtain the same sound you got, wouldn't it be important to know what type of fuzz you were using?

Fripp: No. I can get that same sound with every kind of fuzz box I've ever used. It's not a question of equipment.

Source: https://www.elephant-talk.com/wiki/Interview_with_Robert_Fripp_in_Guitar_Player_(1974)

In that interview he says he prefered the Buzzaround but it was not on his pedalboard in 1974, it was a Guild Foxy Lady, Guilds version of the Big Muff Fuzz.

fripp1974.jpg
 
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I think Mr. Fripp has thrown down the gauntlet. You mission, should you decide to accept it, it to find settings on a BuzzAround and on a Big Muff that produce the same tone, using a Les Paul. Clones are acceptable.
 
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Two years ago at the King Crimson Camp (https://www.threeofaperfectpair.com/) I had the pleasure to play Games Without Frontiers with Tony Levin. After us it was Adrian Belew's turn and he didn't have his Parker so he ask to borrow my Fernandes.

It didn't sound "normal" anymore, it sounded 100% Belew. It was a hard slap on my face and quite a reality check...

But I will still want to do a Buzzaround, and Muff from here even if equipment is not important. ;)

EDIT: Holy schnoute! I never had a peek at the build documentation and see that in fact many variant are possible with Muffin Fuzz PCB!

I'm not a pedal guru like you guys but when I check https://tagboardeffects.blogspot.com/2012/09/guild-foxey-lady-3-knob.html I see mention of 4 1N4148 and a 1N5817. The doc of Muffin Fuzz here has only 4 diodes... General Gadget (http://www.generalguitargadgets.com/pdf/ggg_foxy_lo.pdf) is also different.

I love my experience so far with PedalPCB and would prefer to stuck with it. Any recommendation to which Muffin Fuzz would be closest to Guild one?
 
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None of them are the Guild Foxey Lady component values. I found this schematic on Kit Rae's Big Muff Pi page. If anyone knows Big Muffs, it's Kit. In the caption above this schematic he identifies this as the design used for the Guild Foxey Lady. You can sub 470pF or 510pF for the 500pF caps. Sub 3.9nF for the .004µF cap. I'd use log taper A100K for VOLUME and linear B100K for SUSTAIN and TONE. Do not feel obligated to use carbon comp resistors, they are noisy, use metal film. Use film caps for 3.9nF, 10nF & 100nF. I prefer silver mica or film over ceramic for the 500pF caps. Any high-gain low-noise Si transistor will work; the usual suspects are: BC109C, MPSA18, 2N5088, 2N5089, 2N5210. 1N4148 is equivalent to 1N914. The 1N5817 is not shown in the Muffin BOM, but it is on the board and on the schematic. For RLED, use 4.7K if your LED is red. Use 2.7K if your LED is green or blue.


V1_Big_Muff_67_No_1_schematic.jpg
 
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Chuck D. Bones said:
None of them are the Guild Foxey Lady component values. I found this schematic on Kit Rae's Big Muff Pi page. If anyone knows Big Muffs, it's Kit. In the caption above this schematic he identifies this as the design used for the Guild Foxey Lady. You can sub 470pF or 510pF for the 500pF caps. Sub 3.9nF for the .004µF cap. I'd use log taper A100K for VOLUME and linear B100K for SUSTAIN and TONE. Do not feel obligated to use carbon comp resistors, they are noisy, use metal film. Use film caps for 3.9nF, 10nF & 100nF. I prefer silver mica or film over ceramic for the 500pF caps. Any high-gain low-noise Si transistor will work; the usual suspects are: BC109C, MPSA18, 2N5088, 2N5089, 2N5210. 1N4148 is equivalent to 1N914. The 1N5817 is not shown in the Muffin BOM, but it is on the board and on the schematic. For RLED, use 4.7K if your LED is red. Use 2.7K if your LED is green or blue.
Click to expand...

Hello @Chuck D. Bones , I'm trying to follow you recommandations but I'm a bit lost...

From Muffin Fuzz (https://docs.pedalpcb.com/project/MuffinFuzz.pdf) I see 3 different BOM that got pieces you mentioned related to BigMuffPage schematic but since I don't know nothing about electronic it would be helpful if you could suggest one of those to start and change values:

Green Russian
Civilian
Triangle
Double G
Martian Fuzz
Bigger Muffin
Stomp '75
Mask Us

Thanks in advance,
Dali
 
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For a new builder I recommend starting by building a project without changing the values to avoid making the project more difficult. You should be able to find PCBs for some of the more popular ones, and that is a great place to start. Here is a link to a pcb with a build document that walks you through some changes you can make to it, but evev this can be more confusing than starting with one specific board.

check out the detailed build document first: https://guitarpcb.com/wp-content/uploads/2018/06/BD_BMP-MUFFN-2018-V3.pdf

board: https://guitarpcb.com/product/big-muff-pi-classic-muffn-10-variant-7-mods/
 
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I agree with zgrav. Unless you have experience modding pedals, I'd build one exactly per the build docs. Most of the Muff variants are not going to sound all that different. If you build the Triangle, you'll be pretty damned close to the Foxey Lady.
 
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Robert said:
Docs have been updated to include "The Fox" variant.
Click to expand...
Greatest customer service ever. Thanks a lot!

May I suggest you point out in the description that 9 variations are included. It will help people find it. ex:

"Compare to EHX Big Muff Pi (9 variations in the building docs)"

or even better because the keywords will give weight:

"Compare to EHX Big Muff Pi (also included in the building docs: Russian, Foxey, Triangle and 6 others)"
 
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