Friday, 30 March 2012

Vintage Treble/Bass Boosters - I can't find the Germanium!

*This page also has a schematic for the Fred Briggs Rangemaster*

So, we all know there are many vintage treble/bass booster designs out there that were developed in the 1960s which were designed to give your tube amp the extra kick it needed to get some lovely tube saturation. Even with the huge number of modern stompboxes that promise to give you the ultimate booster people still love the old designs and cherish the tones they provide. But here's the problem; the increasing rarity of the key germanium transistors which are required to give them their original vintage vibe. Anyone who has built a germanium based pedal recently can testify that finding germanium transistors with the correct gain and leakage characteristics can be a frustrating (and expensive!) experience.

So, what to do? Easy, come up with a new design that still gives all those vintage tones but uses easy to source parts. However, before we start lets have a look at some of the more popular vintage boosters that are out there. Firstly the legendary Dallas Rangemaster:


And the Apollo Treble/Bass booster:

The Hornby Skewes Selectatone Treble/Bass Booster:


The Hornby Skewes Treble Booster:

This unit also built with an OC44 Ge Transistor

And the Orange / Vox / Apollo Treble/Bass Booster:


Ok, so what am I suggesting we do? Find some germanium, that's what we need to do - easily obtainable germanium. Impossible? No. The Russians were using germanium for a long time after the West stopped and their production methods produced transistors that were a lot more consistent than our attempts.

For example I have a pack of 50 MP14b transistors I bought on a whim from ebay for about £10. I tested them all and 95% of them came back good with gains from 25-40hfe and leakages of less than 200mA (most were less than 100mA!). Very nice, but the gains are a little low. Luckily there is a little trick in transistor land called the "darlington configuration": http://en.wikipedia.org/wiki/Darlington_transistor

Configuring transistors like in essence creates a single transistor which has a gain equal to the product of the gain's of the two individual transistors. Ok, so if I have two transistors each with a gain of only 25hfe I end up with one transistor with a gain of 625... Hmmm, far too much, but there is a way to force the circuit to think the gain is lower. Pete Moore of Diystompboxes.org did this:


Using a low gain (~50hfe) OC44 and a medium gain silicon transistor) he created a hybrid Rangemaster he called the "Rangepig". It sounds great and using the 100k trim pot you can blend in the amount of germanium "dirt" you want while still gaining the bite and gain characteristics of the silicon transistor. Does it sound like an original Rangemaster? Well, no, not completely but it does sound pretty damn good and it really adds an extra dimension to the age old design.

MartyMart makes this comment on the circuit:

"Pete posted this up a week or so ago and it's a wonderful circuit. Built with an OC44 and a 2N3906, I used 47n in/out caps, so it's a bit more of a full range pig! Great "twist" on a rangemaster, which has a gorgeous clear sparkle to it, like a nice "sheen" to chords/picking. The 100k trimmer lets you dial in some Ge "grit" or you can leave it very smooth. A great "boosting" tool for sure.

10/10, thanks Pete for a simple/great sounding gift!"

Another option is to not use germanium at all and go for easy to obtain silicon transistors. Here's a circuit presented by Will Firstbrook (strangely enough also called the Rangepig!):


This circuit uses piggybacked (where have we seen those before?!) silicon transistors to emulate the lower gain of germanium devices. Another advantage of this circuit is that is NPN negative ground so can be used with a standard power supply without causing problems when you connect other pedals. You could of course build Pete Moore's Rangepig as NPN but germanium npn transistors are hard to find...

I've tried both of these circuits and played around with them both a bit too on a breadboard. So, which do I prefer? I prefer Pete Moore's Rangepig. I think it allows you to still get the classic germanium tone while also allowing you to dial in some more gain if you like. Using cheap but consistent Russian germanium transistors let you get the same result everytime without having to spend mega bucks on sourcing some ultra rare decent OC44s. Don't get me wrong though, Will's Rangepig still sounds damn good, it just doesn't have quite the same tweak-ability that I enjoy so much about Pete's design.

*UPDATE* Here's a schematic for my version of the Rangemaster, incorporating Pete's darlington transistors and a few circuit mods that are about for the Rangemaster:


Nine Volt Nirvana - Fuzz Pedals and Boosters


Nine Volt Nirvana Fuzz pedals have been around since the late 1990s, some of Joe Gagan's designs were what got me interested in stompboxes back in the early 2000s. Now Nine Volt Nirvana is no longer around, luckily Joe drew out circuit schematics around for his pedals so that clever DIYers like yourselves could make your own.

Here's the schematics for his coolest stuff:

Firstly the "Bronto Booster" - this one is a favourite of many gain freaks and does everything from straight boost through to great fuzz tones. Here's a demo of the Bronto Boost in action:



The "Easy Face" was a really popular build in the early days of the DIY scene and was capable of creating some really cool Fuzz Face tones. The combination of a silicon transistor for Q1 and a germanium transistor in Q2 set the foundation for many boutique Fuzz pedals for the years that followed.

Here's a demo of the GT Fuzz  and Dino Drive in action:



The "Sky Ripper" Fuzz was one of the first pedals I ever built and I've still got it around (Somewhere!). I built this one as I couldn't find a schematic for the then uber-secret Zvex Fuzz Factory. It's so tweakable it's mindbending when you get into it. I think I spent three weeks playing this pedal solidly and I still didn't find all the tones that it was capable of. When I built the Zvex Fuzz Factory a few years later it was a close match between these two as to which I liked best. I never really decided and I have both in my Fuzz collection. The Sky Ripper could almost count as a synth on it's own!



So there they are, some of Nine Volt Nirvana's best pedals. If you've got a stash of germanium transistors get building some of them (especially the Bronto Boost, the Easy Face and the Sky Ripper) - you won't be disappointed :-)

Wednesday, 28 March 2012

Fred Briggs - Unknown Fuzz



A new fuzz design from myself. It's silicon transistor based but with a difference. I've been playing around with the old Vox Tonebender circuit for a while and this is what sprung from those experimentsTaking inspiration from the Fred Briggs Fuzz I made a few years ago that used "piggy-backed" silicon transistors to emulate lower gain germanium devices I used a couple of piggy backed high gain silicon trannys in the first stage with the hfe set to 25. This first stage pushes a NOS BC108 transistor in the second stage - it sounds great, there's no ear shredding like the usual silicon fuzz boxes just a nice fat low end and a warm mid section. The three controls are for 1; a bass cut, 2; a width control (which adjusts how "wide" and gainy the fuzz sounds) and the third is just a volume control. As you can see there is no "usual" gain control, that's because the only gain control you need is your guitar's volume knob, it'll do everything from mild overdrive right through to full on FuZzZzZzZz.

So, here's the schematic for you:


*NOTE* - To further control the high end and upper mids I would recommend you add in a 2n2 cap in parallel with the 22K resistor and 100kB "Width" pot. It really calms down the harsh frequencies. I included the 2n2 cap on my final build!

*NOTE 2* - Piggy backed transistors are a little picky, you may have to pair up a few 2N5088 transistors before you find a couple that are happy together :-)

I'll be updating this with a sound sample as soon as possible!




Tuesday, 27 March 2012

Tim Escobedo - Tytewadd Fuzz


Here's another one of Tim Escobedo's great "circuit snippets" - the Tytewadd Fuzz. As you can see it's reminiscent of his Syrupp Booster:
Using that top jfet as a simple current regulator bangs up the gain in the circuit and allows this single transistor gain stage to create some epically big fuzz tones. I had a play with this the other day and really enjoyed it's tone and simplicity - I would certainly recommend this build for anyone who enjoys Big Muff-ish tones.

Toadworks - Mr Squishy Compressor


I'm a fan of compressors, in my opinion they are the unsung heroes of great guitar tone - they level it all out and give you tone a consistency and sustain that would be impossible to achieve without a compressor. Toadworks have been around for a while now and offer their own compressor the "Mr Squishy". Here's a description from the Toadworks Website:

"ToadWorks Mr. Squishy is an analog compressor pedal that combines purity of tone with tight, punchy squeeze-on-demand. Mr. Squishy has been tested with a wide range of amplifiers, including tube, solid state and hybrid, and it delivers the goods every time.

ToadWorks Mr. Squishy provides great compression without oppression, remaining transparent enough that you never lose the original tonal qualities that made you love your axe in the first place. For years, guitarists have sought a natural sounding compression that did not diminish their tone, and ToadWorks has delivered.

Don't you just hate when you kick on the compressor, and your guitar sound changes? Compressors aren't supposed to do that. ToadWorks Mr. Squishy is the anti-compressor - your tone stays crystal clear and unblemished.

Mr. Squishy provides plenty of squish where you want it, and none where you don't. The Gain, Squish & Level controls allow you to compensate for all manner of differences between guitars, pickup types, etc. Mr. Squishy has a nice, tight attack, and a long, slow release, giving you the best of both worlds. Mr. Squishy won't distort unless you want it to; there is no buffer, the Op-Amp can be overdriven, but that's what the Gain control is for. And when you listen to the sound clips, notice that the Level is always around six... want to guess what happens if you turn off the Squish, crank the Gain, and set the Level at 10? A very serious clean boost that will overdrive your amp's input. Yes, that's right - Mr. Squishy can double as perfect clean boost, with power to spare."

And here's a demo of the Mr Squishy in action:


Well, thanks to phibes and aegert over at freestompboxes.org the Mr Squishy has been gutted and here's the schematic: http://www.box.com/s/194dc32665d393373c68


As you can see the circuit is a tuned variation of the original Dan Armstrong "Orange Squeezer" opamp/jfet based compressor:


This type of compressor is a good option if you are looking for a more transparent compression with a less evident "squish" on the tone (a quick attack/release time). You can get some distortion caused by overloading the input and forcing the attenuation jfet to clip but overall this compressor design works well for it's simplicity.

For further reading here's the freestompboxes.org forum topic: http://freestompboxes.org/viewtopic.php?f=7&t=16760

Thursday, 22 March 2012

Sola Sound / Vox - Tone Bender 3 Knob (MKIII) / Fulltone - Soul Bender

[NOTE - This post also contains details of the Fulltone Soul Bender]

Vox Tone Bender Mark III
Introduced in 1968 the Sola Sound Tone Bender MKIII is the last in the line up of the classic Tone Bender circuits. It produces a more mellow, less aggressive fuzz than the MKI & MKII Tone Bender circuits. Once again it uses a 3 transistor design but the structure is significantly different to previous incarnations of the Tone Bender. As you can see below the Tone Bender MKIII came in various guises:

Sola Sound Tone Bender MKIII
Colorsound Tone Bender MKIII
Another Sola Sound unit
Sola Sound Tone Bender MKIII Gutshot
Now although the fuzz produced by the MKIII isn't as agressive as previous Tone Benders it can still produce an unholy amount of Fuzz. Here's a demo video of the MKIII Tone Bender circuit in action (Note - it's a Pigdog MKIII):


Here's the schematic for the most widely distributed version of the Sola Sound Tone Bender MKIII:


In the original the transistors were unmarked PNP Germanium and the diode was a 1N270. I'd recommend using a pair of lower gain (40-60 hfe) for Q1 and Q2 and a higher gain 90-120hfe for Q3. If you want to see the variations on the Tone Bender MKIII design then check out: http://fuzzcentral.ssguitar.com/3knob.php, there are details on the Park Fuzz Sound and Prescription Electronics Yard Box there.

Here's a vero layout created by Electric Warrior (Note - he used a 250K Volume pot):


And here's some images of his completed build:


And here's some info regarding the Fulltone Soul Bender:

And a description:

"Our Soul-Bender is based on the legendary Colorsound and Vox Series III ToneBenders made by Sola-Sound/England in the late '60's that was used by Beck and Page on much of their circa 1968-70 recordings.

Equipped with 3 gain-matched germanium transistor for a FAT, searing lead tone, I also made the Tone control response and range more usable and much less shrill sounding... Full clockwise is SMOOTH sounding.

The Soul-Bender cleans up when you back-off on the guitar's volume control. This pedal has tons of tonal character and even harmonics and of course, true bypass w/ LED is included with every one."
And a vero layout for the "Boutique Bender":


For more info on the Sola Sound Tone Bender MKIII check out Effects Database here: http://www.effectsdatabase.com/model/solasound/tonebender/mk3

And here's the Freestompboxes.org forum topic: http://www.freestompboxes.org/viewtopic.php?f=19&t=7728

Wednesday, 21 March 2012

Builder Overview - Pigdog Effects

Pigdog Fuzz 1.5 - Tone Bender MK1.5 Replica
Pigdog Fuzz 1.5 Gutshot
Pigdog Effects are the creations of Steve Williams and they're grown in his organic pedal allotment which is located in London, England. As you can see from the images above and below his creations are some of the finest available - the build quality and aesthetic is second to none; just check out those gutshots. Here's a small interview with Steve that was conducted by Bart over at the great www.Effectsdatabase.comhttp://www.effectsdatabase.com/interviews/brands/pigdog

Black Case Pigdog Fuzz 1.5
Gutshot of Black Case Pigdog Fuzz 1.5
Pigdog Fuzz 1.5 & II Combo (Tonebender MK1.5 & MKII Pro)
Gutshot of Pigdog combo
Pigdog Mini Competition Driver (Rangemaster + input cap blend)
Gutshot of Pigdog Mini Comp Driver
Pigdog Tonebender MKII Professional Rebuild
Gutshot of Tonebender MKII Rebuild
Pigdog Fuzz (MKIII Tone Bender Replica)
Check out the construction method here on the Pigdog Tone Bender MKI replica below and compare it to the original Tone Bender MKI - The case is a replica of the original MKI folded steel case the circuit is constructed point to point on a through hole board - replicating the exact manner in which the original MKI Tone Benders were made. Even the same brand of capacitors have been sourced as NOS:

Pigdog Tone Bender MKI

Original Sola Sound LTD Tone Bender MKI
Gutshot of Pigdog Tone Bender MKI
And this Loony has had a coat of green speckled Nitro applied, check out the effect it has on the Hammerite case:

Pigdog Loony (Tone Bender MKI Replica)
Pigdog Loony Gutshot
Pigdog Electric Eye Fuzz
Pigdog Electric Eye Gutshot
And now a few demo videos of Pigdog pedals in action - it's the Loony first then the Electric Eye and finally the Pigdog Mother:


So there you go - top quality building and great tones too what more do you want? If you want to know more about Pigdog check out: http://www.pigdogpedals.co.uk/ (Note- the website is still under construction but there is an email address there). Or alternatively if you visit the D*A*M Forum his username is "dazed and confused".