RangeMaster – Pedal Progression 1

In this series I revisit and re-build some of my favorite guitar pedals. Here a treble booster is given some of the best vintage parts possible, protection circuitry, power supply filtering, a negative voltage supply, some indication circuitry, and a, very, shiny housing.

With over a decade building guitar effects some have unavoidable ended up broken or where less than perfectly put together originally. With what I now know the effect units can be upgraded and/or fixed. Here I especially include a find of the Texas Instruments CV7003 Transistor, made in England a military version of the OC44, this was the original unit I used over a decade ago that did end up broken and rare then almost impossible to find now, I did however recently got very lucky. I mananged to grab two of the last resonable units from one supplier (low leakage= low noise, high Hfe = enough gain).

First, sorting out the power section, the effect runs on “negative” voltage as a PNP germanium transistor the OC44 or military version CV7003, so needs either a battery or a voltage inverter circuit to be able to use your regular guitar pedal supplies. For this best use is the max1044 a couple of capacitors, and a separate board of input filtering. Here I also ad the protection circuit suggested and re-used from RG Keen. So if someone sees the word “Rangemaster” knows enought that they run on negative 9V and plugs in an inverted supply, the very rare transistor is not forever lost. To fit everything I split the power sections up on separate little daughter boards, one protecting the input and supplying filtering, the other carrying the MAX1044, a good guide is found in ‘Madbeans’ guides, look under archive >here<.

Next I’d like some indication for the ‘full’ switch that increase the frequency range of the Rangemaster boost. Here there are several solutions such as the ‘millennium switch‘ or an idea by Joe Davisson, having several 2n3904s left over from getting the perfect pairs in a phaser I used the suggestion of Jack Orman, also having a very nice low parts count. Worked great, and using a tiny square round top that discreetly pops up.

Finished everything is very snuggly fitted but, do fit..

The main effect is placed on the original re-used and butchered board from 2011, not bothering cleaning this one up the lead-dress is rather sloppy. Powered by Two 47uF caps from Sprague TE, very nice ones I had on hand, and managed to scrounge up some input capacitor of the Mullard 60’s ‘tropical fish’ variety, (called so because of the color bands). These parts have some influence of the tone, input caps sets the amount of bass roll-off, and are selectable with a separate toggle (imagine the difference between Tony Iommi of Black Sabbath, and Brian May of queen both need and use the Treble Booster as their core sound). These capacitors do however do a good job at preserving high treble notes. As the output capacitor I use a New old stock Polystyrene capacitor, commonly used where preserving treble notes are crucial (and was used in the original units in the 60’s/70’s).

For resistors I customary use Dale RN military(for power), and PRP(for signal) resistors, not that it matters here, really. One of the resistors are switched out for a tiny Vishay multi-turn potentiometer, this is so the transistor bias can be set more acurately, also meaning it can be tuned by both ear and by reading voltages, very useful indeed..

The case is a left-over spare originally for a D.A.M. Meathead that I didn’t really care for at the time, custom made copper painted hammond 1590A box, badly drilled for a much smaller effect, I only just where able to fit everything, one of the reasons splitting things up on different PCB’s. Adding a nice lense for the LED and a label printed on some very old adhesive clear film, a good tip here is to afterwards spray the label down with clearcoat it does protect and blend it into the base color and brings out the black on the print.

Very happy with this, came out nice and made up from a selection of left-over and really precious parts. Sound-wise there are plenty of things to listen to, try youtube, but what I really enjoy with this is that it lend itself to great blusey rock to classic rock, while also together with a strong buffer manages to push a high-gain amp into nice saturation needed in Metal, as it does bring forward the mid and upper-mid frequencies, shelving of bass that otherwise muddies a Metal sound of many many high gain amps.