Hiwatt DR504 Head

The DR504 head is the DR103 with half the output section: the same hand-wired Dave Reeves circuit, two EL34s instead of four, and 50 watts, which brings the point where the amp begins to break up down to something a studio can use.

Normal and Bright channels carry independent high- and low-impedance inputs and independent volumes, so jumping them with a patch lead turns those two knobs into a tone control. Four ECC83s run the preamp, and the rear-panel impedance selector covers 4, 8 and 16 ohms.

Wattage	50W
Channels	Normal, Bright
Inputs	Normal Hi; Normal Low; Bright Hi; Bright Low
Output	2 x 1/4" Speaker Out
Preamp Valves	4 x ECC83 (12AX7)
Output Valves	2 x EL34
Controls	Normal Volume; Bright Volume; 3-Band EQ shared by both channels - Bass, Treble, Middle; Presence - Treble Boost shared by both channels; Master Volume; Standby - On/Off; Mains - On/Off
Impedance	Switchable using Impedance Selector on the rear panel - 4 Ω, 8 Ω, or 16 Ω