Friday, November 30, 2012

Bending your Tone for Page

The Led Bender mkII
The UK fuzz mania began in 1965 probably after the Rolling Stones recorded the 3 fuzz notes that changed the history of rock'n roll: the opening notes for their hit "Satisfaction". First recorded on Brian Jones' Harmonica in Chicago and 2 days later by Richards using a Maestro Fuzz Tone, the opening notes were meant to be replaced with a horn section later on, but luckily producer Andrew Oldham decided to keep it as it was. The song was an immediate hit across both sides of the Atlantic and fuzz was the talk of the day. Guitar legend Vic Flick, the man begind the James Bond Theme, brought the American Fuzz-tone (FZ-1) to the UK and asked electronics engineer Gary Stewart Hurst if he could modify the unit to increase the tone sustain. Hurst used a similar 3 transistors architecture and designed the first Tone Bender, referred today as the mkI. Within a year or so a plethora of fuzz pedals were issued by various brands like the Arbiter Fuzz Face and the Baldwin Burns Buzzaround. While the Fuzz Face became the most famous fuzz of them all, the Tone Bender was probably the highest selling unit ever due to the fact that it was issued under various brands like Sola Sound, Vox, Rotosound and Marshall. The MKI version was made famous by the Beatles (Rubber Soul), Mick Ronson (Ziggy's Spiders from Mars), Pete Townsend and Jeff Beck.

Jimmy Pages' Bender original receipt (left) and the Sola Sound reissue of the mkII (right)

Despite its legendary sound, the Tone Bender mkI's sound and design was not flawless. Circuit was sensitive to gain tolerances of the transistors and the sound was buzzier than some wanted. A new 2 transistor design was issued by Sola Sound and is referred to as mk1.5. This design could probably be the original 2 transistor design which Arbiter issued during 1966 as the Fuzz Face. The circuit was more stable, the sound was richer and saturation was not too heavy. The huge success of the Fuzz Face drove the competition further and Sola Sound made the leap to a 3 transistor architecture but this time it was a first amplification stage driving a Fuzz Face style 2 tranny stage with Germanium OC75 or OC81D were used on all 3. Different brands featured similar mkII design using various transistors, and they all were successful throughout the late 60's and 70's. When referring to legends like Jimmy Page and his tone on the Led Zeppelin I and II albums from 1969 the Tone Bender mkII is considered to be a major factor.

The Led Bender mkII
Even more variant and diverse than the Tone Bender mkII of the Fuzz Faces is the Tone Bender mkIII which was issued 1968 and sparked a whole different era of fuzz pedals which led to the birth of the Big Muff.

After building more then a few fuzz pedals I decided to get into the Tone Bender jungle. I realized that I really wanted the mkI and the mkII, but the mkI seemed tricky and risky so I took the mkII path. Now Germanium trannys are always expensive and I found some silicon versions which got good reviews so I decided to give it a go.

After many unsuccessful attempts on various schematics I found one which worked, sounded good and by replacing trannys I really managed to get that bendery tone I was aiming for: Raw, punchy and versatile. Once you go for the Whole Lotta Love riff with humbuckers or How Many More Times with a Tele, you'll know this is the one.

I started with the GGG NPN design modded by J. Orman and B. Trembley which is a good choice. You can find the schematic here, but I really wanted to have the extra Tone control so I went the Hot Silicon path  designed by Gus Smalley. The schematic is shown here. The two designs are quite alike and sound more or less the same depending on the transistors used. I took Mictester's and JD Sleep's advise of putting low gain sets and went to buy the 2N2369 parts instead of BC109C or 2N5088. I ended up using 2N2369 for Q1, 2N3904 for Q2, BC109C for Q3 and 2N2369 for Q4 for the TONE stage. I also liked the FAT switch which switches between low and high values of the input cap. Once I got that Jimmy Page sound I called it a day and painted the new Led Bender in a Zeppelin homage style.
Gut shot of the Led Bender. VR1 is a pot on the right side.
Might as well change it to a  board resistor.

I am sure this is not the end of my Tone Bender phase but it sure sounds great, I am getting a friend to lend me his Sola Sound reissue of the mkII professional and I'll compare the two. Meanwhile I play Good Times Bad Times using this little baby connected to the Runoffgroove Supro amp emulation pedal and with the right  reverb I can nail that super tone. A major milestone in my Fuzz quest.






15 comments:

  1. you should include gut shots.

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  2. Heloo, i´ve build the Mictester´s 3 knob silicon tonebender with bc549c as replacement for the suggested bc109. Although the general sound is not that bad with this trainies, i´m having that synthy noise during the decay. Reading your post, seems that low gain traines really matters in this design despite Mictester´s advice to use bc109 in his schem... do you have such "synth" effect with high gain transistors in your build? Thanks in advance and sry for the poor english!

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    Replies
    1. I am working on adding audio clips and gut shots for all my pedals and I am starting with this one as there is some interest in it.
      There is some synthy decay noise but it is really not that bad. I get it only on specific settings and not on all the rage but you can solve it by biasing the transistors.
      I did add a bias pot to get this fixed. I will add more info once I recheck my build.

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    2. OK, The Mictester schematic has VR1 from the Fuzz pot (abuse) to the ground. I had some experimentation before I decided where to leave it. It's a trade off between splatty and edgy so somewhere in the middle was perfect for me. When The Abuse knob (Fuzz) is cranked up it gets more splatty and synthy decays start crawling in and when it's fully CW I get a lot of noise so I don't go full CW.
      2N2369 gave me the best vintage results by far. Higher gain gets you towards Big Muff territory and that was not what I wanted with this one.

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  3. Which paint is used for the yellow-gold color?

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    Replies
    1. The Gold color was the original powder cast enclosure by Mammoth Electronics:
      http://www.mammothelectronics.com/ProductDetails.asp?ProductCode=500-1001
      Gold Antique color on a 1590BB Aluminum enclosure.
      The Black paint or for that matter all the paint I ever use for Aluminum enclosures is Glass or Ceramic paint, used with pure sable brushes.

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  4. hi there

    i'm interested in buying your led bender. how much do you want for it?

    please contact me: rivercash@hotmail.ch

    shaun

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  5. Correct transistors used for all stages updated above. Fantastic results.
    Q1, Q4 - 2N2369
    Q2 - 2N3904
    Q3 - BC109C

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  6. i think i sounds like shit, not even close to a Mk1 or LedZep, sorry, but i think you have to tweek some more or go get your ears checked ;)

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    Replies
    1. Well that's good, because it's not supposed to be an MK1. MK1 is really a different circuit and much closer to the Maestro Fuzz Tone.
      The MKII and the Led Bender are not all that different and I do have to tweak a bit more. Nevertheless, the Page sound is 20% pedal. The other 80% are fingers, strings, pickups, amp, Echoplex preamp, microphone techniques and a whole lotta attitude.
      btw, you can always get your opinion heard without being a dip shit ;)

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  7. Hi, i've just built this pedal, used bc109 (instead of bc109c, is there any difference ?). My problem is that it crackles with the fuzz knob fully down and completely distorted fully up. I also noticed that the q3 collector voltage was (0.82).
    Could you tell me what did i do wrong ?

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    Replies
    1. Forgot to say i used the hot silicon schematic. (sorry for bad English)

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    2. Sounds like a transistor issue. I also tested BC108 and BC109 and they all came out OK. try to reduce gain on Q1 and Q2 by using lower gain trans.
      Perhaps the 2N222A will yield better results.

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