The making of the
Story by: Ad van Dongen
During the development of the BuffTool© and the related browsing on the internet I came across a review of the Dallas Arbiter Rangemaster. It appeared to be the “Holy Grail” for Rock & Blues guitarist by giving the guitar player a dynamic, sensitive signal boost that will retain the character of the guitar played. It was developed in mid 1960’ties and used by Eric Clapton, Rory Gallagher, David Gilmour, Ritchie Blackmore, Tony Iommi and Bryan May to create their unique guitar sounds.
Attracted by this review I started looking into the technical background of the Treble Booster and ordering a few Germanium transistors for building a prototype. I build a hand wired prototype and tested it on a Sunday evening. I was really amazed by the dynamics of this effect. I phoned Paul and that week he tested the first TrebleTool© prototype on several amps. Again the conclusion was that this effect is a really dynamic and transparent effect that creates addiction, you can’t stop playing! After the initial testing I went back to do some research on the essential core of a good treble booster, the germanium transistor. I bought several batches of various types of germanium transistors like AC122, AC125, AC128, OC44(K), OC45, OC70, OC71, OC72, OC75, OC76, CV7003, NKT275 and 2SB405K.
It was confirmed that not all germaniums sound good, even within the range of one type of transistor. The average reject rate, depending on the type of transistor is from 30 up to 60% The story behind this can be found on several websites explaining the technical background of the Rangemaster technology with regard to the gain, leakage current, hiss and tone characteristics of germanium transistors .
During the "Quest" for good, consistent germanium transistors I came across a batch of New Old Stock (NOS) transistors with a consistent quality and perfectly fit for using in a Treble Booster. I bought several batches of these. Based on this transistors I have build a second prototype
Paul tested the prototypes and stated that it’s a very useful and dynamic effect but next to this statement he confronted me with a challenge; “it’s only interesting when it can be used in conjunction with EMG’s and Wireless systems because a lot of my professional customers use these”. This is one of the major problems of the original Dallas Rangemaster and most of the Rangemaster clones, they will not except active outputs (like EMG’s, wireless- or loop systems) in front of it because it will make the booster sound shrill and thin. The next two weeks after this statement I spend experimenting with an interface to reproduce the passive pickup /cable impedance needed to make the TrebleTool© sound good with active elements in front of it. This resulted in the ICI (Impedance Conversion Interface) that converts the active output signal in a signal that can be used to drive the TrebleTool©. Paul tested the upgraded prototype and it passed!.
In this period of experimenting with the first prototype a friend and customer of Paul, Gert-Jan Roemen (playing in the Thin Lizzy coverband Parris ), offered us to use him as a guinea pig testing the TrebleTool© prototypes live on stage. He provided valuable feedback on the practical use of the effect. His feedback, like not using fragile mini switches, are integrated in the third prototype version of the TrebleTool©.
Now I knew that we were on the good track to finalize the prototype and go for a production version, I inventoried the extra features that would be useful to integrate in the production version. The resulting feature list is
- Impedance Conversion Interface converting an active input signal to a signal suited for the TrebleTool and thus retaining the character of the effect
- Continuous variable range setting from Treble to Full boost to dial in the amount of Bass with a specific guitar type or element combination
- Pre warning Battery low indication giving the opportunity to changeover batteries before the effect stops working
- External power supply (noise reduced) providing the option to use an external power supply without inducing noise or changing the character of the sound. This is a common problem with the Rangemaster (clones)
- Reverse and over voltage protection to protect the sensitive germanium transistor and keeping the pedal running for many years to come
- Radio Frequency Interference (RFI) suppression, avoiding radio signal reception when using high gain setting in combination with turning down guitar volume. This is a common problem using high gain boost effects, caused by the antenna effect of the guitar cable
- True bypass footswitch to switch effect on & off to avoid tone sucking in bypass operation.
These features were finally integrated in the last prototype and tested live on stage, resulting in the development of the production version called the TrebleTool©.
”