The RM-1 is a faithful reproduction of the single transistor Dallas Rangemaster, one of the best treble boost circuits to ever hit the front of an amp. The updates to the circuit are minimal, and consist of both input and output resistance to eliminate pops when using the footswitch (very high impedance to remove voltage build up without affecting the signal), a diode to protect against reverse voltage, an easily removeable attenuator to make the output of the RM-1 more compatible with downstream effects, a thermal stability diode connected in the output section to allow the pedal to operate in high temperatures without dropping out or changing tone, and true bypass switching.
If you use vintage amps from the 60s (Silvertone, Univox, Tiesco, etc.) and thought that they were just a little bit lethargic, the RM-1 will breathe new life into them.
I am always amazed just how well this little circuit pushes the front end of the amp and the way it responds to dynamics of hitting the strings, with more bite on the top end without being harsh.
The LEVEL knob allows you to go from clean boost to mild overdrive, allowing you to control the amount of gain with your guitar/bass volume knob. This is a great “always on” pedal for the first stage of your pedalboard.
The RM-1 uses a vintage PNP Germanium transistor and will run off a positive barrel power supply (standard these days) putting out 9-12VDC. Internally, a charge pump is converting the negative ground voltage into a positive ground voltage so the RM-1 will live comfortably on a pedalboard using the same power as current negative ground supply pedals.
Never use more than 12VDC into the unit as it will render the charge pump inoperative, and you’ll need to have the pedal repaired.
The 2nd Wind series does not use internal batteries.
Output level info:
The voltage divider on the output brings the level back down to a usable level and will make downstream pedals happy- for driving an amp directly (guitar/bass>RM-1>tube amp), the unit can easily be adjusted to full output by removing one connection on the bottom of the circuit board, clipping at the two red lines will remove the attenuator and the resistor can stay where it is:
Reverse by reconnecting the resistor.
Frequency/Gain adjustment jumpers
There are two jumpers under the bottom cover the user can use to tailor the frequency response of the RM-1. From the factory, both jumpers are installed, this is the default setting. In the frequency sweep diagram below, the highest trace is the default setting from the factory, both jumpers on , the middle trace is with only the “Lows” jumper installed, and the bottom trace is the original Rangemaster response- classic treble boost.
Here is a demo of the RM-1 into a Lovepedal Pickle Vibe into my 1963 Fender Bassman into a 2/12 cab. I am using the OX to send a signal to my DAW which is using Reaper. The guitar is a Fender Baritone Tele. Any gain changes heard is all from changing the volume on the guitar only, this RM-1 has both jumpers installed and is NOT using the output attenuator, so the front end of the Bassman is getting a robust signal. Notice that even when the attenuator on the output is disabled, you are still able to dial your guitars volume back for a clean signal, rich in harmonics.