Sunday, 18 June 2017

Tubeworks Real Tube 903 Modded Tone Stacks

So as most of you guys know when I'm studying for exams I tend to do a bunch of layouts when taking breaks to keep my sanity. So since I did a layout for the Tubeworks 903 I thought to myself if it's basically a tube pre-amp I thought why couldn't the tone stack be modded to that of some legendary amps. With that in mind, I modified the original layout I made with various tone stacks.

Original schematic can be found on Revolutiondeux.

Layout 1: Fender

Layout 2: Marshall

Layout 3: Vox

Layout 4: Hiawatt DR103

Layout 5: Sunn 1st Gen Model T

Layout 6: Orange OR120 MKII

Layout 7: Matamp GT120

Layout 8: 72 Ampeg SVT

Layout 9: Marshall Superbass

Layout 10: Dumble Overdrive Special 70's

Layout 11: Dumble Overdrive Special '97

Saturday, 17 June 2017

Tubeworks Real Tube 903

JohnK had made a layout for the 903 awhile ago, and since I did a layout for the 901 i thought I'd see if I could make a smaller layout for the 903 to make it easier to put this in a 1590BB with plenty of room. I took his switch wiring to make it true bypass, and removed the additional LED to tell you that it's got power, which I feel is unnecessary. Schematic can be found on Revolutiondeux.

Tubeworks Real Tube 901

JohnK had made a layout for the 903 awhile ago, so I thought I'd give the 901 a shot. The layout should be small enough to give you plenty of room in a 1590BB. I took his switch wiring to make it true bypass, and removed the additional LED to tell you that it's got power, which I feel is unnecessary. Schematic can be found on Revolutiondeux.

The 901 has higher gain then the 903.

Friday, 16 June 2017

Electro-Harmonix Signal Pad

With 1000 verified layouts in site, I figured I'd throw in something small, simple, and usable.

From the Source:

The Signal Pad is a passive attenuator that allows you to instantly switch to a different preset volume. It's like your guitar's volume knob, with a fully-passive and color-free circuit. Leave your amp's volume set high for overdrive, and use the Signal Pad to lower your level for a clean sound -- then switch it off to kick in your amp's natural overdrive. You can also experiment with the Signal Pad anywhere in your effects chain -- you'll bring out new tonal combinations from your favorite old pedals.

Basically a simple switchable volume pedal.

Monday, 12 June 2017

Mictester - Silicon Tonebender

Found this while searching for some schematics for Silicon Tonebenders I came across it on revolutiondeux. Miro posted a layout awhile ago for the Hot Silicon, which is pretty much the same, the difference being the trimmer off the gain control (abuse) which lets you set the gain rather then having a set resistor. Since my layout different then his, and the added trimmer I figured it was worth adding.

Here's mictester's advice on tweaking:

"Adjustment: set the 1k "Abuse" pot halfway. Play though it, and adjust 5k preset until "gating" just stops. That's it!

You'll find that it has plenty of output, that the "Abuse" control gives a good range of colour, the "Sparkle" control has a very wide range and the sound is remarkably reminiscent of early Jeff Beck (certainly not a bad thing!).

Possible mods:

Put small value capacitors from base to collector of the middle two transistors - start with 47pF. This "smooths out" the sound a lot, but reduces the treble available.

If you have radio interference, put 100pF from base of the first transistor to ground.

Experiment with the capacitor values in the tone control - the 8n2 could go as low as 3n3, which would give a ridiculous range of treble control!

Increase the value of the 47k feedback / bias resistor - try as high as 470k. The gain will rise, the touch sensitivity will disappear, and it will become a high gain screaming monster! "

Silicon Tonebender MKII

I saw a request for a Silicon Tonebender MKII based on a perfboard layout over on StompBoXed's page, which is the modified Tonebender MK II Professional. So after making a layout for it I started searching for other Silicon Tonebenders.The other 2 schematics can be found over at DIYSB.

Silicon Tonebender MKII

Silicon Tonebender MKII Professional


Silicon Tonebender MKII Professional Mod

Saturday, 10 June 2017

Rockett 10 Ton Hammer

"The Rockett Pedals 10 Ton Hammer is a perfect distortion pedal for players who have a clean amp, like a Fender. It may not play nicely with high gain amplifiers, thats just the nature of the high gain game. This is a highly responsive pedal, and with some creative use of your guitars volume and tone knobs, you can even achieve some bluesier tones for added versatility. But really, subtlety isnt this pedals primary job. It is here to crush, kill, and destroy, but in a very musical and harmonically rich way. Get back in tune with the old school overdrives that made you wanna rip some killer riffs and leads in the first place. The Rockett Pedals 10 Ton Hammer will unleash a pummeling tone with all the intensity of a monstrous wall of distortion"
Original FSB thread and schematic available here.
Layout Updated! Connected 10K resistor from Bass 1 to Ground instead of Vb.

Sunday, 28 May 2017

Darkglass Microtubes B3K

"The Microtubes B3K is an unusual tool - a perfect combination of brutality and clarity. It delivers defined and powerful saturation in an intuitive format. There are no rules and no limits, so dig in and unleash your tone.

Level: Sets the volume of the overdriven signal.
Drive: Sets the amount of saturation in the overdriven signal.
Blend: Mixes the clean input signal with the overdriven signal. The clean signal remains at unity gain while the volume of the overdriven signal is set by the Level knob, allowing for fine control of the blend ratio.
Grunt Switch: Sets the amount of low frequency content to saturate by selecting between three different bass boost levels before the clipping stage.
Attack Switch: Sets the amount of treble content to saturate: The œBoost setting emphasizes the treble content extra clarity and presence. The œFlat position leaves this register untouched while the œCut position will reduce the amount of high frequencies being saturated. This new addition helps to keep the treble portion of the signal under control, specially useful when playing with new strings and/or cabinets with tweeters.

You can find the original FSB thread and schematic here.

The layout (like the Friedman BE-OD) has been verified as "working" in the forum section but the original has been built using SMD components and there's been some "guessing" in some of the values.
I don't know how close it is to the B3K (it may be 100%) but this is the best schematic we can get at the moment.

Friday, 26 May 2017

Locobox Mysto-Dysto Distortion Unit

Very little info around on this late 70's / early 80's unit. Check the FSB thread for details. I snatched the image off from fxdb...

Now. What's this all about.. The way i see it, we have a buffered OD250/Dist+ gain stage (including clipping diodes shunt to ground), followed by a sort-of active BMP tone stack and an output buffering. It may not sound all that great as it is, but there is a lot of room for your own improvements. First of all, one could up the input cap for 47n or 100n and up the 47n coming from distortion control for 220n or even 470n to get a lot more lows through. Next, the tone stack is quite abysmal. I would probably double the cap values there too. Then the unity amplifier making the tone stack active is what it is - an unity amplifier. Either lower the input resistor from 100K to 47K or up the feedback resistor from 100K to 220K. That should make the circuit roar. Also, for added stability, up the filter caps to choice. And finally, try on a few different diode setups for the clippers. Not all of these may be required to nail your new favorite tone, but most of them should be worth a try. Anyway. Maybe you should try and have your way with this one.

Tuesday, 23 May 2017

Noah'sArk Distortion "M"

Not much info around of this japanese "Marshall in a box" type distortion. It does sound pretty good though.. Junko seems a bit nervous on the demo.

Thursday, 18 May 2017

Catalinbread Katzenkönig

Damn i like this brand. Cool, great sounding designs and lots of them. And i was surprised the schematic was up at their site. I only have a few originals, but i'm strongly tempted to get more..

Info from Catalinbread:
We combined the best elements of a Tone Bender MkII fuzz with a Rat distortion to create something that sings like a fuzz but is tight like a distortion. It loves humbuckers and single coils. It loves your cranked amp and your super-clean amp.

Katzenkönig was tuned to offer a huge range of response – from a really beautiful singing tone, to tight, harmonically-rich crunch, all the way to fuzz mayhem.
A simple, four-knob control scheme allows you to dial in your sound quickly and without much fuss:
INPUT – Controls the input sensitivity. Turn it down when using higher output pickups and humbuckers or to dial in your wah sound (more on that later). Turn it up for lower output pickups or for when you want to go over-the-top!
GAIN – Controls the gain of the second gain stage. It is not a conventional gain control, rather, it controls the amount of negative feedback in that stage. What does that mean for you? It means you get a wide ranging gain control that sounds great throughout it’s entire rotation!
FILTER – Allows you to dial in your final tone from smooth and creamy all the way to bright and cutting. You can quickly find the sweet spot for your rig with this control. If you are familiar with the Filter control on a Rat then what you’ll find is that this is an even better version of that idea!
VOLUME – Standard volume control. You’ll find that Katzenkönig sounds great turned down quiet or cranked up and loud!

To get familiar with your new Katzenkönig, let’s begin by plugging it straight into your amp set to a clean sound with no other pedals in the chain.
Set the controls as follows: Volume – noon, Filter – noon, Gain – minimum, Input – minimum.
Now play a bit to get a feel for how it responds. Go ahead and mess with the Filter knob to see how it works. You’ll notice that unlike most fuzz and distortion pedals, Katzenkönig sounds great at minimum gain settings.
Now go ahead and start experimenting with the Gain and Input controls. You’ll notice that they both increase gain but in different ways. Leave one at minimum and start turning the other up. Then leave the other at minimum and turn the other one up. And yes, cranking them both up leads to extreme fuzz, sustain, and saturation!
At lower Gain and Input settings, Katzenkönig’s response is tight, like a great distortion pedal. You can play chugging, palm-muted riffs that you wouldn’t be able to get away with on a standard fuzz pedal. But turn up the Gain and Input, and you can get those epic harmonic blooms that you normally associate with a great fuzz pedal!


Monday, 15 May 2017

Friedman BE-OD

"Designed by tone-guru-to-the-stars David Friedman, the BE-OD overdrive pedal faithfully captures the sonic impact of Friedman’s legendary BE-100 amplifier–known in some circles as the Brown Eye, and favored by serious musicians the world over. The BE-OD overdrive delivers authentic tube amplifier sound from a compact pedal with the controls needed to shape your tone, including volume, gain, tight, bass, treble and presence. These responsive knobs will take you from light, slightly broken-up overdrives to straight-up gain nirvana"
Original FSB thread and schematic available here.

09/06/17 Layout updated! Schematic and layout have now been corrected. Thanks to Ciaran, Pakrat, Destro and the others on FSB for all their work.
If you've already built the previous layout and want to correct it:
- Remove C2. The remaining 10n cap that connected to it becomes 100n and needs to go to ground instead of V+.
- Change the 120p between the TL074's pins 1 & 2 to 47p.
- Change the 100R resistor to 10R.
- C1 is now 47p.
- The 10n cap next to the trimmer is now 100p.
- The link under the trimmer (from lug 1 to lug 2) needs to be moved up one row (between lug 2 and lug 3). Eliminate the cut under the trimmer by jumping it left to right.

Saturday, 13 May 2017

J. D. Barbato Buttercup Fuzz

Description and info at freestompboxes. Seemed like a nice vintage fuzz adaptation and thus, a cool addition to our library.

Wednesday, 10 May 2017

Black Arts Toneworks Revelation Super Lead

From the source:

A revelation. Stripped down all out amp pusher. The Revelation has a trio of controls. Pre Gain, Gain, and Volume. LOTS of volume. Pre Gain sets the overall gain level of the device, the gain control dials in the correct amount of distortion and the volume knob absolutely slays the front end of your amp. Think of the Revelation as an extension of your amp’s pre section. Use it to push your amp into super creamy saturation, use it to boost your riffs into full and thick exaggerations of your amp’s base tone. The Revelation does not alter your tone, just makes MORE of it. Choose the Revelation to hammer your amp.

The SuperLead version of the Revelation is a rawer, more aggressive take on the circuit. A bit gnarlier, mid focused, aggressive sound. Specifically tuned for guitar, and baritone guitars, choose the SuperLead for a fuller, fatter, more saturated and aggressive sound.

While there is no schematic for this one I did some comparison between the Black Arts Toneworks Revelation Super Bass and the Pharaoh, and what I noticed is that the values are identical, with the tone control removed. This leads me to be fairly certain that the Black Arts Toneworks Revelation Super Lead is the same concept, but with the values for the LSTR, since the tonal description matches that of the comparisons between the Pharaoh and LSTR. So I figured since I had the layout out to modify it to match the Oath (Black Arts Toneworks Revelation Super Bass without pots) I might as well take the time to change it over to the Black Arts Toneworks Revelation Super Lead as well.

So it's a striped down LSTR without the tonestack.

Black Arts Toneworks Oath

Essentially the oath is the Black Arts Revelation Superbass without any knobs. After VisualFuzz found an image of the Oaths board, and having to enhancing it to see the resistor values without the image being distorted I'm pretty certain that I've got the values and placements for the resistors to replace the pots.


Tuesday, 9 May 2017

Barcus Berry 3000A Buffer Preamp EQ

I know, I know. Another day another layout from me. I mean Jez, can't I let one of the other guys post a new layout for once this month? You guys must be sick of seeing my name pop up with a new layout... Anyways, this time I decided to do something different the the massive amounts of fuzzes I've been doing.

I've seen a few posts in the requests over the years for people looking for a preamp for Piezo pickups. The Barcus Berry 3000A is designed to work for acoustic piezo pickups but is also a buffer, preamp, and EQ. This is the only info that I could find on it:

The Barcus Berry 3000AE Piezo Buffer Preamp with EQ is specifically designed to work with all Barcus-Berry electret microphone systems. Features external bass, treble and volume frequency controls to allow a wide range of adjustment. Includes a belt clip for unrestricted movement.

 Barcus Berry 3000AE Piezo Buffer Preamp Features: 

• Designed to work with all Barcus-Berry electret condenser mic systems.
• Features external bass, treble and volume frequency controls for a wide range of adjustment.
 Barcus Berry 3000A Product Specifications:
Input (EQ) Flat
Input Interface: RCA unbalanced
Input Impedance: 2.2 Meg Ohms
Maximum Input Level: 2.0 vrms
Output (EQ Flat, Volume Max)
Interface: 1/4" unbalanced
Impedance: 2K Ohms
THD: .008% @ 1kHz
Noise: -92dBu
S/N: 100dB
Bass: +/- 12dB @ 50Hz
Treble: +/- 12dB @ 10kHz
Frequency Response: 5 Hz - 30kHz (+/- 1 dB) Power Supply

From what I see from the schematic I have no question that it will work with any Piezo pickup, as there doesn't seem to be anything really special to tell me it can only work with theirs. Mostly it's just marketing to get you to buy their pickup.

Sunday, 7 May 2017

Emanating Fist Electronics Black Dust - Tone Distorter

From the captain:

Dig it. Black Dust. The Black Acid pre-set to fold air. Fuzz and drive, wide open. Maximum attack, minimized footprint. Fuelled with the same PCB as the Black Acid, British made Magnatec BC109's, Arcol carbon comps, BC/Vishay capacitors, prime cuts all the way.

For those not familiar with this circuit type it has a very similar tonal qualities to the old Meathead Dark though I'd say a more refined approach with a more traditional overall tone than that of any Meathead. The mids are quite flat the lows considerably boosted and the highs pretty natural and open sounding. Heaviness, it is some.

There were 2 versions, a big box version (older) and smaller (newer).

Big Box Version:

Small Box Version:

Emanating Fist Electronics Black Acid - Tone Distorter

From the captain:

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.

Emanating Fist Electronics Dope Priest - Frequency Sustainer

From the captain:

Take 3. D*A*M Ram Head -> Emanating Fist Electronics XB-70 -> Emanating Fist Electronics Dope Priest. Same shit just a little more refined with an air of maturity, if the Ram Head was a bottle of Jim Beam the Priest is a bottle of Wild Turkey. As with the XB-70 the core circuit influence here is my slowly decaying 1977 Guild Foxey Lady though this time the circuit blue print is tailored to my own ears and tastes rather than just replication. I've taken some influence from V3 Sovteks and the Triangle Muffs, basically lowered background noise, tighter projection and greater ability to cut through dense frequencies. It ain't no reinvention of the wheel just the delivery of sounds that I dig in regards to this circuit type presented in way that appeals to me more than our past incarnations.

Original Pedal:

With a Mids Switch:

Emanating Fist Electronics XB-70

Direct from the captain:

The origin of the idea was to be able to make some Ram Head's at some point with and greater ease. I don't really care to do that to be quite frank, old shit is old, so I have opted for this route. The XB-70 is a Big Muff, but to be precise, a clone of my Guild Foxy Lady...that I think is from around 1977!?!? I can't quite recall to be honest. The year ain't important, though the fact it sounds like torn leather soaked in piss and salt smushed lovingly into ears does. It is a brute of a pedal, has a really intense roar at full tilt, like any good Big Muff really. Though my Guild has the extra added bonus of insanely loud background noise and batshit crazy amounts of feedback ladened sustain. So the XB-70 takes this particular Guild box as a reference point though assembled so it's a little more polite but still packing mucho fire in tah belly. As much fun as it would have been to clone that throwing shit at the walls amount craziness into these for the most part the old Guild sounds that way because one of the transistors is fucked. In other words, most sane folk would consider a pedal that they had purchased that sounded this way to be very defective.

So to summarize. The X8-70 is a Guild Foxey Lady replica, from around the time EH were knocking out the Ram Head Muffs, that has a bad attitude but will play nice and not hurt your feelings.

Original Pedal:

With Mids Switch:

Saturday, 6 May 2017

Black Arts Toneworks Revelation Super Bass

Direct from the source:

A revelation. Stripped down all out amp pusher. The Revelation has a trio of controls. Pre Gain, Gain, and Volume. LOTS of volume. Pre Gain sets the overall gain level of the device, the gain control dials in the correct amount of distortion and the volume knob absolutely slays the front end of your amp. Think of the Revelation as an extension of your amp’s pre section. Use it to push your amp into super creamy saturation, use it to boost your riffs into full and thick exaggerations of your amp’s base tone. The Revelation does not alter your tone, just makes MORE of it. Choose the Revelation to hammer your amp.

The SuperBass version of the Revelation is a rounder, more dynamic take on the circuit. A bit bassier, gruffer, throatier sound. Works equally well for guitar or bass, choose the SuperBass for a fuller, fatter sound.

After looking at the schematic it seems like a really stripped down big muff, and I mean stripped down. In particular it's basically the Pharaoh without the tonestack.

On Bass:

On Guitar:

Friday, 5 May 2017

Sola Sound Zonk II

Since I posted layouts for the Hornby Skewes Zonk Machine, version 1 and 2, Will Kenworthy posted links to 2 other schematics that were traced and posted over at the DAM forum for a version of the Zonk II under the Sola Sound name back in the 60's. I figured why not make layouts for them as well.

Version 1

Version 2

Thursday, 4 May 2017

Diaz Texas Square Fuzz

Another day another fuzz. While we have a lot of fuzzface layouts on the site, you can never have too many fuzzface. There seems to be a bunch of different versions, at least a lot of different colors of them. I don't remember where I found this schematic, but it's a pretty good sounding fuzzface, IMHO, that's supposed to sound like SRV's tone.

A description of one of the sellers of the pedal:

The Texas Square face was originally designed as a replacement for Stevie Ray Vaughn's fuzz faces, which were always dying. Cesar built his circuit into one of SRVs dead fuzz face boxes and Stevie used it until his unfortunate death.

The square face is NPN not comes with two germaniums but it has transistor sockets and two silicons are included for more gain. They can also be combined, for different tones. Changing positions will also help!! You can really hear it on the SRV album "IN STEP"

Caline Englishman

Came across the schematic for this one over at FSB, and it's a pretty good marhally sounding OD/Distortion. Made by a company Caline, a Chinese company that sells direct. It's actually stupid cheap, to buy, seen them for sale $35usd new. You may be asking, "well if it's so cheap why spend time making a layout and build it myself?" The answer is simple, we can always improve upon it and use quality components. I mean really, who wants to waste money on something that made to be as cheap as possible.

Wednesday, 3 May 2017

LEHLE Sunday Driver

From the Source:

The Lehle Sunday Driver SW is a compact-format high-end preamp for all types of electrical and acoustic instruments - a preamp that enables electric guitars and basses, acoustic guitars, and also other stringed instruments (such as violins, cellos and double basses) to realize all of their musical potential. The switchable version expands the classical Lehle Sunday Driver's features by an On/Off footswitch. 

The Lehle Sunday Driver SW, with its high-quality JFET technology, provides two operating modes. In D (= Driver) mode, the input signal is amplified with zero modification, to eliminate the signal losses that long cable routings and/or effects chains can cause. The signal remains powerful and clear, and retains its dynamics. Mode S (= Sunday) multiplies input impedance by four, bringing out previously inaudible details and, as gain increases, imparting to the guitar a characteristic and unmistakable warmth. There is no distortion at any stage, and the signal always stays clean, even at a maximum gain setting of 15 dB. Thanks to its studio-standard signal-to-noise ratio of better than -100 dB, the Lehle Sunday Driver SW is totally free of background noise. To exploit the dynamics of tube amplifiers to the full, the input voltage is also rectified from the power supply socket, then filtered, stabilized and doubled to 18V. 

In OFF status, the Lehle Sunday Driver SW provides two different modes of operation - in TB (= True Bypass) mode, the input and output are linked with zero losses to one another via a switch with gold-plated contacts. True Bypass mode is the best option for a small set-up with short cable routings and for when a treble-booster or a classical fuzz pedal is looped in after the Lehle Sunday Driver SW. The line-driver function, located at the start of the train or in an effect chain, is the better solution for long cables and for complex effect board configurations. Switch the Lehle Sunday Driver SW to TS (= True Sound) mode, and it is active as a buffer, without amplifying or modifying the signal in any way. In this mode, the Lehle Sunday Driver SW operates as a totally neutral line-driver – equivalent to Mode D with the gain pot turned all the way to the left. The Bypass mode option enables the Lehle Sunday Driver SW to integrate ideally into any set-up, whether as a battery-operated stand-alone unit, or in an existing pedal board. 

Note: I removed the odd power network, which consisted of a diode rectifier and regulator, which should not be needed since it's supposed to run on +9VDC not +9VAC. According to the site, they claim there's a TB/Buffered switch which is not included on the schematic, nor did I see it on the PCB over at FSB when it was reversed engineered.

Tuesday, 2 May 2017

Hornby Skewes Bass Boost

Another super rare Hornby Skewes pedal, so rare in fact I can't even find a video for it. Similar to the treble booster, but boosts the bass frequencies instead of the treble. I'm certain just like any other vintage Hornby Skewes pedal it's gonna sound great.

Layout 1: Original PNP

Layout 2: NPN Version

Hornby Skewes T.B. 2 Selectatone

Another classic. Not much info on this one either. It's super rare, just like 99% of the Hornby Skewes pedals. Essentially, it's a set booster that you can switch between either bass or treble boost. Rumor has it that it was used by Ritchie Blackmore during the 1960s up until 1974, as well as Jethro Tull on Aqua Lung. Schematic is over at FSB.

 Layout 1: Original (PNP)

Layout 2: NPN

Monday, 1 May 2017

Hornby Skewes Zonk Machine II

Best info I could find on this creamy classic fuzz goodie.

The 1967 John Hornby Skewes Zonk Machine II is an extremely rare, and vintage pedal enthusiasts have long coveted both the original Zonk and its successor, the Zonk II. The Zonk II was the result of a re-engineered Zonk Machine I, which was based upon the Sola Sound MK I Tone Bender circuit. Featuring (2) PNP M2N 4403 Silicon transistors, instead of the earlier (3) Germanium transistor based Zonk Machine I, the Zonk Machine II is more stable, smoother, and less dark sounding. Effectively designed to be a complete and practical unit, the Zonk II’s predecessor was intended to be used in conjunction with the JHS Treble Booster unit (essentially like a Rangemaster) as to enhance the articulation and clarity of the otherwise muddy Zonk. Interestingly, John Hornby Skewes did offer both units within one box, and it was re-branded as the famous Shatterbox.

The rolled steel casing with a blue Hammerite finish is very reminiscent in design to the gold MK I Tone Bender: with two basic controls on top, and the input and output next to one another on the back, the straight-forward aesthetic is a reflection of the absolute perfect simplicity of the circuit within. It is loud, robust, full-range, and complementary with most any rig. It is sweet, subtle, and sings with sustain. Completely inspirational to play through, the Zonk II offers endless enjoyment, and tone otherwise unavailable via a reissue, clone, or kit.

Layout 1: Original PNP

Layout 2: Original NPN

Nocentelli MMR Fuzz

Description for this outide-the-box-thinking fuzz circuit is up at freestompboxes with the original schematic. Seems rather nice.

Hornby Skewes Zonk Machine I

Well got time for another study break, so it's that time for another layout. Just like the last layout I posted, here's another uber rare fuzz, a gift from the fuzz gods that no worshiper of fuzz should be without IMHO.

One of the more famous Tone Bender MKI influenced fuzz boxes and now almost as legendary as its golden cousin was the John Hornby Skewes Zonk Machine. A little more wacky in the graphics department, but not as heavy duty or robust as the MKI, the Zonk Machine was almost identical in its circuitry. Made between 1965 and 1966 in Leeds, England, the Zonk Machine like the MKI was only made in small numbers before the pedal was updated with a more modern and easier to produce unit.

Layout 1: Original PNP

Layout 2: Original NPN

Some suggested gains and tips I found over at DIYSB:

One suggestion with the leakage:

Values taken from an Original Unit
Q1=TI AO2 650 Hfe= 180, leakage= 0.12mA.
Q2=Mullard OC75 Hfe= 78, leakage= 0.29mA
Q3=OC44 Hfe= 58, leakage= 0

Tips for other builders interested in the Zonk Machine:

1. Socket all transistors because you’re likely to go through a bunch of them before you find some that work well.

2. The Zonk is very bright. Play around with the input cap and try values between .001uF and .01uF. Maybe even set up a three way switch to toggle between different values.

3. Definitely use a log/audio taper “Fuzz” pot. I used linear at first but it greatly limits the useful range of the pot. The name “Fuzz” is a bit of a misnomer as it doesn’t really fulfill most people’s definition of a fuzz control. It essentially adjusts the bias of Q2. The Sola Sound Tonebender Mk1, which is a topographically identical circuit (sans the 33K resistor), called this pot “Attack” which is a bit more appropriate IMO.

4. Set up an SPST switch to bypass the 2.2M resistor for nasty, all-out craziness!

5. Some came with 25k Log Fuzz pot, and 220k resistor instead of 470k.