Warwick Quad VI

600W at 4 Ohms

12AX7 Preamp

EL84 before mosfet power amp

Front Panel

• GAIN Control + LED to adjust the input level.
• LED Indicator
• QUADRUMATRIX Control* for maximum versatility
• LOW BOOST  Switch + LED to Boost low frequencies
• BASS  Rotary control to Cut or Boost low frequencies
• MID 1 Rotary control to Cut or Boost low-mid frequencies
• SHIFT 1  Switch + LED to set the operating frequency of Low Mid
• MID 2 Rotary control to Cut or Boost high-mid frequencies
• SHIFT 2  Switch + LED to set the operating frequency of High mid
• TREBLE Rotary control to Cut or Boost highfrequencies
• HIGH BOOST  Switch + LED to Boost highfrequencies
• PHONES Headphone inout socket
• MUTE Switch + LED mutes all the outputs of the Quad except the PHONES socket and
• simultaneously activates the TUNER OUT socket on Rear Panel). 
• When the MUTE switch is depressed, the LED shines red. In an operation ready state, the LED shines green.
• POWER On/Off switch for the Mains Power.
• MASTER volume.

 Rear Panel

• MAINS IN AC
• GROUND LIFT Switch 
• TUNER OUT Socket for a tuning device. 
• LINE OUT Output for connection to an external power stage 
• DI PRE/POST Switch
• DI OUT Balanced output
• EFF. SEND & EFF. RETURN  
• EFF MIX control determine the degree to which
• the effects within the parallel loop affect the signal.
• SPEAKER OUT : XLR & Speakon

QUADRUMATRIX control*

Each position offers a unique preamp-shaped voice with the tone controls shifting to accommodate each. Positions 1 and 2 bypass the EL84 output tube, using only the 12AX7 preamp tubes. Positions 3 and 4 unleash the full potential of the output tube and transformer. Position 2 offers the flattest response, while positions 1 and 4 have more extreme shaping.

Source: https://reverb.com/item/312004-warwick-quad-vi-tube-bass-amp-head-w-skb-case