Seymour Duncan - Tweak Fuzz  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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analogguru
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Post by analogguru »

Here is the:

Seymour Duncan Tweak Fuzz schematic
Seymour Duncan Tweak Fuzz schematic
Seymour Duncan Tweak Fuzz schematic
enjoy,
analogguru

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modman
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Post by modman »

Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

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lynessmy
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Post by lynessmy »

How are them compared? The link doesn't work...

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BeAR
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Post by BeAR »

Thanks to analogguru, I just built this stomp box. Schematic is spot on and sounds killer too!
Hope these help others. The ceramic on the bottom of the board just parallels up the 22pf on the top of the board as I didnt have a 47pf lying around.
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BeAR
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Post by BeAR »

Just another quick update if anyone cares, Ive been playing around with the 2 transistors in the tweak fuzz and Ive found a better combination . Q1 is now a BC550 and Q2 is a BS170. This gives a tighter more focussed fuzz without the wooly bottom end when the tweak knob is wound arount to the 2.2uf cap.

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marshmellow
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Post by marshmellow »

A BS170? You replaced a bipolar transistor with a switching MOSFET??

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Post by flood »

marshmellow wrote:A BS170? You replaced a bipolar transistor with a switching MOSFET??
:scratch: +1

holy p-n junctions, batman!
In the interest of full disclosure, I am Animal Factory Amplification.

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lynessmy
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Post by lynessmy »

What a nice PCB from BEar. I gonna make this PCB.

In fact, I had drawn one and tried on the weekend. But it doesn't work.
With the audio probe, i found that there are no signal passing thru the selectable CAP, no matter in which position.
Can anyone help me to understand what went wrong? I didn't pop in the 1M pull down resistor.

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BeAR
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Post by BeAR »

Yeah I know, strange but it works a treat. There is a discussion in the Workbench section about it. Some fets seem to bias just right as a direct replacement. As I said in that post, it shouldnt work, but it sounds better than any other option Ive tried.

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iggy23
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Post by iggy23 »

has somebody a vero layout???? :roll:

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Post by B3ar »

I got a good deal on a new Tweak Fuzz and am quite pleased with the implementation of SMD -- there are through-holes next to the SMD transistors and resistors, while the caps are already through-hole. Cheap to manufacture, easy to mod -- thanks, guys!

Folks mention that since it's a FF, mod accordingly, and apparently there's a popular easy variant on the Roger Mayer "volume" mods out there. (Remove R5, change R4 to 8k2.) I'm going to try some of the standard value tweaks over on R.G.'s Geofex page, especially those that are just resistor changes.

But I wanted to ask whether anyone has sub'ed out the stock SMD transistors, and whether it was particularly life changing. This is my first FF and I'm not unhappy with the base tone, but I want to be sure I'm not missing the boat.

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Post by holgar »

Thanx for the shem,
this Fuzz Face got the right name, because it is so easy to tweak.
For some more volume I lifted R4 to 1K. For biasing Q2 I took 10K at R5 (4,8V).
Instead of the useles C5 120n I took a Mullard 0,022uF, because I was missing a position 2,5 on the Tweak knob.
Of course the Mullard mojo oozes now through the whole circuit ;-)

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Post by biglouis »

Does anyone have the schematic?

The analogguru link is offline.

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Post by LooseCannon »

Same question here.

Does anyone have the schematic?

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karul
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Post by karul »

here it is
Attachments
SeymourDuncan_TweakFuzz.gif

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Post by LooseCannon »

Thanks!

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Post by stilwel »

FYI....I believe Q1 and Q2 are mislabeled in the schematic. If you trace out the circuit, Q2 on the PCB is actually the input buffer transistor.

I have 2 Tweak Fuzz pedals here, both have Rev A PCBs. Maybe they changed it on a later revision?

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Anyway, I'm in the process of looking for some BC183 BC183C transistors for this beastie and discovered this tonight...thought I'd share.

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Completed builds: Fuzzrite (Si and Ge versions) , univibe, companion fuzz, fuzz face(si version), FY-6 super fuzz, FZ-1S, Scrambler, Tone Bender MkI (nearly complete). I have modded my vox v847,Seymour Duncan tweak fuzz, my bass and my guitar ( slightly).
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Post by ljn »

I just tried the resistor values suggested by holgar on my tweak fuzz. It sounds better than ever.

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