Akashic Guitar effects circuit lookup
BIAS TRIMCONTROL 1CONTROL 2CONTROL 3

Enclosure not stated · 4 knobs

Revolution Deux

Fred Briggs Rangemaster

Based on the Dallas Arbiter Rangemaster· 36 other boards clone it

Category
Boost
Controls
Bias trim · Control 1 · Control 2 · Control 3
Price
see vendor
Read the post at Revolution Deux Schematic image

From the vendor

The author's own Rangemaster (2012), using Pete Moore's germanium/silicon Darlington pair (a ~50 hFE germanium Q1 and a ~250 hFE silicon Q2) with a few common Rangemaster mods. It runs from -9V with a polarity diode.

Bias Q2's collector to -6.6V using the 10K trimmer.

Schematic

The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.

Parts list 15 rows

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Check before you build · 2 values the reader of this schematic was not sure of
  • The three panel pots are numbered 1-3 on the drawing but not named; pot 3 (10KA) is the output level, pot 2 (100KB) sits between Q1 and Q2 as in the Rangepig, and pot 1 (100K) with a 2.2u cap bypasses the 4.7n input cap.
  • The polarity diode's type is not given.
RefValueNormalizedTypeNotes
Resistors 3
R12.2M2.2Minput pull-down; read from the schematic by eye
R2470K470kread from the schematic by eye
R368K68kread from the schematic by eye
Capacitors 5
C147u47usupply filter, electrolytic; read from the schematic by eye
C24.7n4.7ninput; read from the schematic by eye
C32.2u2.2uelectrolytic, in series with pot 1; read from the schematic by eye
C447u47uemitter bypass, electrolytic; read from the schematic by eye
C510n10noutput; read from the schematic by eye
Diodes 1
D1??polarity protection; read from the schematic by eye
Transistors 2
Q1??low-gain germanium, ~50 hFE; read from the schematic by eye
Q2??medium-gain silicon, ~250 hFE; read from the schematic by eye
Potentiometers 4
Bias trim10K10kPotentiometeremitter trimmer; set Q2 collector to -6.6V; read from the schematic by eye
Control 1100K100kPotentiometercircled 1, with the 2.2u cap; read from the schematic by eye
Control 2B100KB100kPotentiometercircled 2, between Q1 and Q2; read from the schematic by eye
Control 3A10KA10kPotentiometercircled 3, collector load and output; read from the schematic by eye

Other boards based on the Dallas Arbiter Rangemaster