Construction details Guitar in Tune Treble Booster
With parts that are readily available you can build the Dallas Rangemaster treble booster simply yourselves. In the Netherlands you can purchase the parts at for example Radio Twenthe in Den Haag
Prototype of the Guitar in Tune Dallas Rangemaster Treble Booster
On an experimental piece of wood I build and tested the prototype.
After the prototype of the Dallas Range master functioned satisfactorily I build the final version.
Because I wanted to drive a transistor amplifier, I have added the volume potentiometer in the circuit.
When you use a tube amplifier it is best to stick to the original design.
After the prototype of the Dallas Range master functioned satisfactorily I build the final version.
Because I wanted to drive a transistor amplifier, I have added the volume potentiometer in the circuit.
When you use a tube amplifier it is best to stick to the original design.
The electrical circuit of the modified Guitar in Tune Dallas Rangemaster
Setting up the Dallas Rangemaster
The resistors of 68K and 3,9K must be tuned for each OC44 transistor to make sure the transistor is in the correct operating area.
Connect, instead of the fixed resistors, two variable potentiometers and set them to respectively 68K and 3,9K. Connect a fresh battery and measure the the collector voltage. Adjust the resistance of the 68K potentiometer in such a way that the voltage is between -6,8V and -7,1V. If you have to control back the 68K resistance to far, then correct the 3,9K resistor. If the resistances are(< 27K / >82K) or (<2,7K / >5,1K) then try another transistor. Use only old germanium OC44 transistors. When the voltage is correct then replace the potentiometers for the same value fixed resisters.
Only use metal film resistors to reduce hiss to a minimum. In itself a treble booster generates additional hiss because of the high amplification of mid and high tones.
Connect, instead of the fixed resistors, two variable potentiometers and set them to respectively 68K and 3,9K. Connect a fresh battery and measure the the collector voltage. Adjust the resistance of the 68K potentiometer in such a way that the voltage is between -6,8V and -7,1V. If you have to control back the 68K resistance to far, then correct the 3,9K resistor. If the resistances are(< 27K / >82K) or (<2,7K / >5,1K) then try another transistor. Use only old germanium OC44 transistors. When the voltage is correct then replace the potentiometers for the same value fixed resisters.
Only use metal film resistors to reduce hiss to a minimum. In itself a treble booster generates additional hiss because of the high amplification of mid and high tones.
The circuit is simple and can be build on a simple strip with solder pins
Example case Treble Booster
To house the Treble Booster all sorts of cases can be used. Make sure you use a metal case for HF screening.
