Marshall DSL20HR Head Electric Guitar Head. The Marshall DSL20HR Head is a 20-watt electric guitar tube head with 3 ECC83 valves, 2 EL34 valves, 2 channels (Classic Gain/Ultra Gain), controls (Classic Gain Ch.) Gain, Volume, Channel Select Switch, (Ultra Gain Ch.) Gain, Volume, Tone Shift Switch, Treble, Middle, Bass, Presence, Resonance, Reverb, High/Low Output (20W/10W), FX Loop, Audio In, Emulated Out
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