Rockett WTF Fuzz  [traced]

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mmolteratx
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Post by mmolteratx »

Found this picture online and decided to figure out what it was. The two 560k resistors were a dead giveaway that it was Bosstone based, so I figured I'd fill in the blanks. Not sure if this is 100% accurate (and I'd hazard a guess that it isn't since I don't know what the value of the Epcos cap and that little MLC cap are), but I built it up and it sounded pretty close to the sound in the demo videos I watched. I omitted switching and the boost function (just switches between two volume controls) on the schematic.

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My build (I also included an input cap switch and omitted the 18nF option at the output):

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Post by B3ar »

Does the Boost knob and switch just trace out to being an alternate volume control? That's showing up a bunch lately, like the lead switch in the Tym J Mascis fuzz.

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Post by mmolteratx »

B3ar wrote:Does the Boost knob and switch just trace out to being an alternate volume control? That's showing up a bunch lately, like the lead switch in the Tym J Mascis fuzz.
Yep. It's another 100kB pot in parallel with the normal one. I guess if you wanted to omit it and have the exact same response, you could use a 50kB volume pot. Sounds just fine with 100k though.

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Post by rabbitgonemad »

Thanks for the schematic and details about the design.
Would you be willing to post the vero layout you designed? I´m half way through comparing the WTF schematic with the existing Bosstone/Boss T-Bone schematics, but I´ve never done a vero layout that from scratch, sorry! I´d highly appreciate your help.
If this is not the right place to ask for this, sorry again, I´m new here.

As an avid PTD User I´d like to do some experimenting with this circuit (transistors, mods, etc.).
Thanks and best regards.

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Post by mmolteratx »

Layout was actually perf with a PC mount WTF pot. Don't have it drawn up, though I guess I can trace it out if I have time. Might as well design one from the ground up though.

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Post by IvIark »

Thanks Matt, here's a vero

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Post by storyboardist »

Here's a perf/PCB layout if anyone wants to go that route.

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Thanks to lvlark for sorting out the boost switch wiring. I think I would have been scratching my head on that one for a while...

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Post by IvIark »

Very nice and tight, great job there.
The vero is verified
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Post by Lawnchair »

Hey, Fuck you mother fuckers!!! :D

Nice job. Though not exactly as I do it. Go with a moderate 5088 and a T0-18 2907 for the tranny's.

You might find that .001 and .0022 make nice light presence cuts without throwing a blanket over it.

Yep. The boost is just my $1.50 boost. Nothing but a second Vol pot.

2k is a good minimum default for the sag. Anything less is pretty stiff.

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Post by Ripdivot »

Lawnchair wrote: Nice job. Though not exactly as I do it. Go with a moderate 5088 and a T0-18 2907 for the tranny's.

You might find that .001 and .0022 make nice light presence cuts without throwing a blanket over it.

Yep. The boost is just my $1.50 boost. Nothing but a second Vol pot.

2k is a good minimum default for the sag. Anything less is pretty stiff.
Cool, thanks for the input! What HFE's are we talking on those transistors? 5088 is Q1 and the 2907 is Q2?

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Post by Lawnchair »

I do have specific numbers I love for each tranny. It's a balance of dynamics, saturation and noise floor as Q2 is not just a buffer.
I use a BC183 in Q1 for some builds and Q2 is adjusted accordingly.

I would socket it up and find your sweet spot with your amp. My Classic 30 clean channel and my Hiwatt require completely different
tranny sets for best performance.

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Post by newly »

Very similar to SATISFACTION FUZZ....who is ripping who?

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Post by mmolteratx »

newly wrote:Very similar to SATISFACTION FUZZ....who is ripping who?
They're both Bosstone derivatives and the WTF (and preceding Trombetta fuzzes) have been out far longer than the Satisfaction.

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Post by MoonWatcher »

mmolteratx wrote:
newly wrote:Very similar to SATISFACTION FUZZ....who is ripping who?
They're both Bosstone derivatives and the WTF (and preceding Trombetta fuzzes) have been out far longer than the Satisfaction.
Then there's the Voodoo Lab Bosstone, which they started producing back in '97. That's almost twenty years ago.

I think some companies like adding the Bosstone to their fuzz circuit roster because it's fairly simple and only needs a pair of easily obtained silicon transistors. It's kind of amazing how much of it they leave verbatim, and then just slap another name on it. I am NOT including Trombetta in the "mostly verbatim" category - I really like those, and what they offer! But when some spendy boutique pedal has even the same 2N2222 and 2N3906 as a low-buck General Guitar Gadgets kit, it makes more sense to get the kit or a used Voodoo Lab pedal (or just do a DIY vero build! :thumbsup ). Like Lawnchair said - most of the magic is in going for the right PAIR of transistors - with so many to choose from (with such a simple circuit), why just stick to the same old same old 2N2222/2N3906 pair?

It's actually FUN to play with the Bosstone circuit and swap transistors. When you hit the sweet spot, you will know it! 8)

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Post by mmolteratx »

MoonWatcher wrote:
mmolteratx wrote:
newly wrote:Very similar to SATISFACTION FUZZ....who is ripping who?
They're both Bosstone derivatives and the WTF (and preceding Trombetta fuzzes) have been out far longer than the Satisfaction.
Then there's the Voodoo Lab Bosstone, which they started producing back in '97. That's almost twenty years ago.

I think some companies like adding the Bosstone to their fuzz circuit roster because it's fairly simple and only needs a pair of easily obtained silicon transistors. It's kind of amazing how much of it they leave verbatim, and then just slap another name on it. I am NOT including Trombetta in the "mostly verbatim" category - I really like those, and what they offer! But when some spendy boutique pedal has even the same 2N2222 and 2N3906 as a low-buck General Guitar Gadgets kit, it makes more sense to get the kit or a used Voodoo Lab pedal (or just do a DIY vero build! :thumbsup ). Like Lawnchair said - most of the magic is in going for the right PAIR of transistors - with so many to choose from (with such a simple circuit), why just stick to the same old same old 2N2222/2N3906 pair?

It's actually FUN to play with the Bosstone circuit and swap transistors. When you hit the sweet spot, you will know it! 8)
Agreed. Which is how I wound up with a 2n404 for Q1 and 2n5133 for Q2. Playing with the emitter resistor on Q1 is also fun.

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Post by MoonWatcher »

mmolteratx wrote:
MoonWatcher wrote:
mmolteratx wrote:
newly wrote:Very similar to SATISFACTION FUZZ....who is ripping who?
They're both Bosstone derivatives and the WTF (and preceding Trombetta fuzzes) have been out far longer than the Satisfaction.
Then there's the Voodoo Lab Bosstone, which they started producing back in '97. That's almost twenty years ago.

I think some companies like adding the Bosstone to their fuzz circuit roster because it's fairly simple and only needs a pair of easily obtained silicon transistors. It's kind of amazing how much of it they leave verbatim, and then just slap another name on it. I am NOT including Trombetta in the "mostly verbatim" category - I really like those, and what they offer! But when some spendy boutique pedal has even the same 2N2222 and 2N3906 as a low-buck General Guitar Gadgets kit, it makes more sense to get the kit or a used Voodoo Lab pedal (or just do a DIY vero build! :thumbsup ). Like Lawnchair said - most of the magic is in going for the right PAIR of transistors - with so many to choose from (with such a simple circuit), why just stick to the same old same old 2N2222/2N3906 pair?

It's actually FUN to play with the Bosstone circuit and swap transistors. When you hit the sweet spot, you will know it! 8)
Agreed. Which is how I wound up with a 2n404 for Q1 and 2n5133 for Q2. Playing with the emitter resistor on Q1 is also fun.
There's just so many parts of the Bosstone circuit that I don't see evidence of established companies ever experimenting with. It's almost like there's even a lack of curiosity. That may be the wrong way to perceive it, but I just have to admit that it's the way it looks to me.

Along with the knee-jerk default transistor pair, why do we always see some stuff like the pair of 560k's on Q1's base? Or the 150k to from base to ground? It's been mentioned that Q2 is more than an output buffer, so how can we change things at it, or before/after it? Is it really groundbreaking to throw some caps on a switch that are parallel to the pair of diodes?

While it's just meaningless spitballing, I think it would be a lot more innovative to play with something like just the IDEA of maybe substituting Q2 and Q3 in a Big Muff with the entire Bosstone circuit. By itself, that's kinda dumb and wouldn't probably amount to anything good sounding, but I think it represents a better starting point. Well, this assumes you're going to spring for what the WTF retails for. Again - not saying it's money wasted, and I generally like Rockett's stuff. I'd just like to see more evidence of things going farther. But I'm just a nut with a hot soldering iron in my hand, so I probably expect more than someone who just plugs stuff in and uses it.

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Post by B3ar »

Anyone care to share their fave hfe pairing for Q1 and Q2? (I've been doing listening tests on clipping diodes, and after a lot of time on that I'm thinking I should get the right transistor pair first and then do the diodes--I'm getting a bunch of suboctave stuff on most diode sets, and not much subtler range. My Q1 is probably 160ish and Q2 300ish.)

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Post by mictester »

B3ar wrote:Anyone care to share their fave hfe pairing for Q1 and Q2? (I've been doing listening tests on clipping diodes, and after a lot of time on that I'm thinking I should get the right transistor pair first and then do the diodes--I'm getting a bunch of suboctave stuff on most diode sets, and not much subtler range. My Q1 is probably 160ish and Q2 300ish.)
BC109B and BC178B. Works every time and has lots of mojo (little metal-canned types).
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Post by B3ar »

I'd have to get out the magnifying glass to check the types, but I settled on 160 hfe for the NPN and 140 on the PNP. Getting a good pair made everything better. Cheap plastic cased stuff from Tsyda, no mojo here other than the right values.

I've settled on 1n4148 and Tayda 1n34a symmetric pairs on the on sides of an on-off-on, and may leave LEDs in the on-board sockets I installed or may go au natural in the middle--both are very nice nice. My base treble cap is a 220pf and I've got a 2k2 resistor to the sag control, but otherwise in line with the schematic. Still picking the tone switch caps--those sockets are indispensable in tuning this guy.

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