The Black Acid is
basically a fuzz face clone (circa 2012). It is a pool of thought and
ideals. All the little iddy biddy nuggets of information learned from
screwing around with this circuit over the last 10 years. Nothing
revolutionary and no reinvention of the wheel just a different slice of
the same cake.
The destination on the trip: The Black Acid has substantial weight and heavy saturation without having a complete strangle hold on the lower frequencies. It has the same perceived amplitude as the old Meathead Dark but with the lows being tighter with greater clarity. It has considerably more output than a stock Fuzz Face but I'd say that it retains more of the vintage nature than any of the Meatheads, I guess you could say the frequency spread is more even. The highs and lows are nicely balanced so the projection is good plus with the mids not being as forced the clean-up from the guitars volume control is very pleasant, though pleasant wasn't really plan here.
The construction style and the internal arrangement is the same as with the Priest. A much simpler circuit with components specially selected to get the job done. At the heart of the Acid is a pair of Magnatec BC109's. UK made transistors don't you know. A great quality component that really complements this circuit set-up. Even running flat-out and blowing the barn doors wide open there is cleanliness or crispness to the tone. Don't get me wrong, it's as sludgy as fuck but sludgy without having cotton wool forced into your ears.
The controls are pretty damn obvious but I'd say the rule of attenuation applies to this pedal, as in I'd advise starting out with the Drive and Fuzz controls wide open and them bringing them back to where you'd like be at. The Fuzz is as you'd find on any Fuzz Face or the Tone Benders Attack control, it's only really gonna kick-in with the heavy on last quarter of the turn. There be plenty of scope for cool tones and amp blending but if you want the heavy open it up. The Drive is basically the pre-gain of the pedal. It's like having your guitars volume control on the floor. The point of this is that it's a great way to un-flab the lows when you're driving the thing hard into the front end of a driven valve amp. It also gives up some great overdrive tones and just makes the box a whole lot more of a flexible tool. The Drive and Fuzz controls also have a pretty sweet interaction thing going off. The Black Acid ain't as 'yeah! lets fucking party!' as the Priest is on the controls front but put the time in and the rewards will be plentiful.
The destination on the trip: The Black Acid has substantial weight and heavy saturation without having a complete strangle hold on the lower frequencies. It has the same perceived amplitude as the old Meathead Dark but with the lows being tighter with greater clarity. It has considerably more output than a stock Fuzz Face but I'd say that it retains more of the vintage nature than any of the Meatheads, I guess you could say the frequency spread is more even. The highs and lows are nicely balanced so the projection is good plus with the mids not being as forced the clean-up from the guitars volume control is very pleasant, though pleasant wasn't really plan here.
The construction style and the internal arrangement is the same as with the Priest. A much simpler circuit with components specially selected to get the job done. At the heart of the Acid is a pair of Magnatec BC109's. UK made transistors don't you know. A great quality component that really complements this circuit set-up. Even running flat-out and blowing the barn doors wide open there is cleanliness or crispness to the tone. Don't get me wrong, it's as sludgy as fuck but sludgy without having cotton wool forced into your ears.
The controls are pretty damn obvious but I'd say the rule of attenuation applies to this pedal, as in I'd advise starting out with the Drive and Fuzz controls wide open and them bringing them back to where you'd like be at. The Fuzz is as you'd find on any Fuzz Face or the Tone Benders Attack control, it's only really gonna kick-in with the heavy on last quarter of the turn. There be plenty of scope for cool tones and amp blending but if you want the heavy open it up. The Drive is basically the pre-gain of the pedal. It's like having your guitars volume control on the floor. The point of this is that it's a great way to un-flab the lows when you're driving the thing hard into the front end of a driven valve amp. It also gives up some great overdrive tones and just makes the box a whole lot more of a flexible tool. The Drive and Fuzz controls also have a pretty sweet interaction thing going off. The Black Acid ain't as 'yeah! lets fucking party!' as the Priest is on the controls front but put the time in and the rewards will be plentiful.
Fuzz 3 to input?
ReplyDeletethanks
no. when i uploaded the layouts from an older version of DIYLC it moved some things and i didn't catch it. the layouts have been fixed and updated.
Deletewow that was fast. thanks, im building right now.
DeleteBuilt and testing against my Meathead Deluxe clone. Similar feel, but the tone is different like it says on the description up top.
ReplyDeletesweet. cheers on the verification.
DeleteDone. Sounds great, no gating in the note decay like my meathead. Great OD when guitar volume is rolled back. Sounds best with fuzz cranked and the drive knob basically adds or subtracts wooliness. Love it. Used bc109b and 109c.
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ReplyDeleteIs the trimmer strictly a tune-by-ear thing or is there a target voltage? Right now I have the voltage on the collector of (I assume) Q1 on 1.44 and it sounds about right.
ReplyDeleteBTW I like this one. Thanks for the layout!
I have Bc108b. Should be better high hfe? 400 or 200 aprox?
ReplyDeleteI was somewhat underwhelmed with my build at first. Maybe I'll have to try out different transistors and mess with the bias. Any suggestions for what transistor hFE and biasing voltages to aim for?
ReplyDeleteThe fuzz also seems to be limited to the very last part of the rotation, so maybe a C1k pot could be better?
With the right transistors this thing is awesome! Went through a bunch of different transistors and ended up with a pair of BC549/BC109 with HFEs close to 300/500. With careful biasing this thing just roars, perfect for heavy riffing. Backing up the drive pot tightens up the fuzz nicely. I'd very much suggest using a C1k pot for fuzz, since the linear pot is somewhat useless around 80 per cent of the rotation. Very good fuzz face with a vintage vibe, but also capable of big heavy riffing.
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ReplyDeleteIs there some way I could do a transistor mod on this, like the switched transistor thing you suggested on the DAM meathead? If so, which transistor would I run to a switch- Q1 or 2?
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteSounds awesome with high gain (about 160 and 295) 2N404As too.
ReplyDeleteHi, I built one of these, but there's no output.
ReplyDelete(I'm assuming Q1 is on the left and Q2 is on the right) I'm getting voltages on Q1 EBC: 0V, 0.58V, 1.44V. Q2 EBC: 1V, 1.44V, 9.57V.
When I audio probe it, Q2e and Q2b are sounding good (fuzz good, level good), but Q2c has significantly lower output than everything else and as a result the volume pot is getting a lower signal. What could be the issue? I'm using BC109 for both transistors, and a 1.5K & 820R in parallel for the 560R.
Only seven years on! Your Q2 voltages are too high, the collector voltage is as high as your supply voltage. Check that your tracks aren't shorting. As an aside, i don't think it's clear that one of the trimmer legs should be removed or an additional cut between the legs leading to Q1 collector (perhaps it's just me!).
DeleteMy mistake, i can now see the orientation of the trimmer is different to what i thought, no need to remove a leg etc.
DeleteThe drive control is an input cap blend, no?
ReplyDeleteAnyone have any idea how to get more volume out of this? It sounds great (built stock to the layout with BC109B/C) but the volume seems a bit weak.
ReplyDeleteconstruction jobs are on the rise again these days because the recession is almost over’ Electronics Quality Engineering
ReplyDelete