Pedal tech

Guitar effect pedal technical resource info:

Some great sounding Treble Boosters through the decades from the 1960s to now:

Dallas Rangemaster, one of the all time greats

Dallas Rangemaster 1960s

Dallas Rangemaster 1960s

Vox Treble Booster: late 1960s/early 1970s

Vox Treble Booster late 1960s/early 1970s

Vox Treble Booster

Nick Thurn 1978 Treble Booster:

Nick Thurn 1978 Treble Booster

Nick Thurn 1978 Treble Booster. Nick is a guitarist who I met in Sydney in 1978 and was an extemely talented electronics technician as well as being an inspiring rock guitarist. Nick was the first guy I ever saw playing a Vox AC30 amp and he used a home made treble booster which was housed in a white painted aluminium box. Nick plugged his beautiful 1969 Stratocaster straight into the treble booster with its volume control set on full and then into the Brilliant Channel of his 1964 AC30. I was floored by Nick’s sound and his aggressive yet fluid playing. Nick had style to burn! We became friends and soon I had tracked down an old 1964 AC30 for myself and shorty after Nick built me a version of his treble booster. The booster sounded marvellous and I used it with my old Stratocaster into a valve WEM copycat echo and AC30 until the booster somehow got lost. Soon after I decided to make another treble booster and Nick taught me how to solder. I bought the parts at Sydney’s Radio House and also from Dick Smith Electronics at St Leonards. My home made NT Booster didn’t sound as good as Nick’s original and I could never work out the reason why. Now I realise that I should have persevered with trying different hfe BC547 transistors and other types of transistors, as well as juggling values of resistors and capacitors. From memory I think that the best transistors I used in this circuit were the BC547s. Later I got interested in other guitars amps and pedals and lost interest in the treble booster concept until the mid 1990s when the Brian May project brought me back to it again and I bought a Guild Brian May guitar which came with its own Guild Brian May treble booster twin transistor unit.

Fryer Ringmaster 2000:

Fryer Ringmaster 2000

Fryer Ringmaster 2000: PNP AC128 Germanium transistor. A slightly unconventional ‘upside down’ PNP circuit a little like we found in the Deacy Amp but this circuit sounded surprisngly good, a very fat sound using the AC128

Fryer Germanium Treble Master 2001: PNP AC128 designed for Guitar Magazine DIY project

Fryer 'Germanium Treble Master' designed 12th Nov 2001 for Dave Petersen's build your own pedal article for Guitar Magazine London.

Fryer ‘Germanium Treble Master’ was drawn up 12th Nov 2001 for Dave Petersen’s build your own pedal article for Guitar Magazine London. This was a simple reworking of the basic Rangemaster circuit using a fatter sounding more powerful AC128 transistor and circuit values which I arrived at after trying test units in my workshop. We used the AC128 transistor in the DIY pedals because it sounded good with many amps and was readily available at the time, and the first pedals were like my prototype model featuring a switchable ‘thin/fat’ input cap giving either 4n7 or another 4n7 cap switched in parallel to produce approx 10nf. The pedal was popular and was issued in 2 runs by Dave Petersen, and was mostly produced in simpler form without the switchable input cap

Experimenter’s DIY Treble Booster Circuit ideas:

Suggested range of values for the experimenter’s DIY Treble Booster schematic: alter component values and transistor types to suit your musical tastes and amplifier requirements.

Capacitors: C1:1nf to 22nf, C2: 10nf to 100nf, C3: 10uf to 470uf electrolytic, C4: 10uf to 220uf electrolytic

Resistors: R1:100K to 1M, R2:100K to 470K, R3:22K to 68K, R4:4K7 to 10K, R5:1K to 3K9, R6:22K to 1M, R7:0 ohms to 1K.

Other things to try: resistor R”X”: 0 ohms to 2K2 this will tend to change the upper mid “focus” of the booster sound with values closer to 2K2 smoothing out this mid focus and lower values (esp 0 ohms) giving a harder more direct rangemaster type focus. Like all things, alter to suit your taste. Capacitor between transistor base and emitter 100pf to 2n2, series resistance between C2 and R6, capacitor between output and ground, R6 resistor as a output level pot, R1 as an input level pot, series resistance 1K after input C1 to assist with RF rejection, R4 collector resistor configured as 10K level pot as per original 1960s rangemaster booster circuit.

Transistor Q1: 2N3904, 2N5088, 2N5089, 2SC1815, 2SC732, BC107, BC108, BC109, BC182, BC183, BC184, BC149, BC173, BC546, BC547, BC548, BC549, MPS8098, MPSA05, MPSA06, MPSA18, MPSA20 as well as other suitable NPN transistors

DIY Treble Booster schematic

DIY Treble Booster schematic

Maybe not one of the greats yet, but with experimentation you can make this circuit above sound great!

Strap mounted mini booster using surface mount components:

I have been asked by Red Special enthusiasts to draw up a cheap good sounding do-it-yourself booster that would be suitable to mount in a lightweight small enclosure on a guitar strap. This uses surface mount components so as to keep the pcb & componentry size small.

This design is experimental and theoretical at this stage because I haven’t made one yet, but is based on other experiments and should work fine. As usual, adjust key areas to suit what sounds best to you.

Strap mounted mini booster using surface mount components

Strap mounted mini booster using surface mount components, gives a low impedance output. 100K level pot can probably be set as a 100K resistor and the booster can just rely on a 47K pot as an output level control for using wireless systems which may be sensitive to higher signal levels from treble boosters. Decoupling is probably not needed on the 9V +ve rail of the emitter follower Q2, but to be safe add a 100R resistor in the +ve rail and 47uf cap to gnd as per the Q1 side. R1 can also be a 4K7 variable resistor.

more guitar pedal info coming