So why do we need a 'Lux'? The Lux Signature amplifier is designed to seek the best possible way to drive a DHT power tube.

Lux Signature 300B SET stereo amplifier

How to drive a DHT power triode

choice #1: pentode. offers necessary single stage gain but high output Z. tendency for highs/lows to be bandwidth limited. Clipping: not nice. Sound is delicate, immediate and pleasant 'bouquet of tone'. Fast! and retrieves the finest details as it sweeps the sonic landscape. Can swing the necessary voltage but but don't ask it to lift heavy objects. the DHT needs more muscle.

choice #2: triode. gain-challenged, needs more than one stage. (Hi gain versions sound like solid state). Low output impedance, wide bandwidth, great slam and dynamics. can be used with a grid choke for greater perceived power. Muscular, but lacks the refinement and delicacy of the best pentodes; leaves behind some of the fine details.

choice #3: re-active interstage. pentode on the input. paralleled sections of a triode with a choke loaded cathode. direct couple to the grid of the DHT.
the DHT gets what it likes: lots of swinging volts and iron fist control, even when driving the grid positve. This is Lux.

the pentode does what it does best: gives tons of voltage gain driving the undemanding load of the re-active tube interstage. The interstage is loaded only with the following grid and cathode choke so bandwidth approaches DC to light and is sonically neutral, no cap coupling to the DHT. The DHT thinks the choke of the interstage is it's very own grid choke. And we still have our pentode!

add to this: dual 5AR4 tube rectification (tubes=tone), dual mono HT AND PS film caps for extra speed, lifting of the veil, no ecap smog

more: WE connection on the 300B for more quiet, more dynamics

Result: tone and refinement of a pentode married with the slam and dynamics of a triode - something like a ballet performed by Superman and Karen Kain?

Lux:
stereo amplifier, dual mono choke loaded power supply AND film caps on the B+ rail to the power tube anode.
2 x 5AR4 tube rectifiers
2 x EF86 pentode input tubes. Roll tubes at this position first. E80F gold pins and 6267 can also be used.
2 x 5687/cathode choke re-active direct coupled interstage
2 x 300B Direct Heat Triode

rich in iron; 2 output transformers, 1 power transformer, 2 power supply chokes, 2 re-active interstage chokes.

Note re 4/8/16ohm speaker taps: Why? It is needed. Really. Nominal impedance ratings are often misleading. An 8 ohm rated speaker may be 6 or 12 ohms and often sounds better on 4 or 16 ohm taps. Always try different taps to determine which gives best sound. When the right tap is selected, soundstage will be bigger and sounds more energetic. Also 16 ohm taps allow using vintage high efficiency speakers. Connecting them to 8 ohms is a compromise.

Specifications: (may change without notice)

• Power output, 300B: 12W peak x 2 RMS @ 1KHZ Class A depending on circuit
• Frequency response: 12Hz to 47KHz (-3 dB@5W) (20hz to 20k -0.5db)
• THD: <1% (1W@1KHz(0.3mv at the speaker outputs)
• Input sensitivity and impedance: 0.5V, 100K
• Power: 110/120/220/230/240V AC +- 10%, 100W
• Dimension (mm): 412(w) x 330(W) x 200(H)
• Weight: 26Kg
• Shipping Weight: 30Kg
• Standard Tubes (priced separately): 300Bx2, EF86x2 (E80F, 6267), 5AR4x2, 5687x2
• Power transformer is low output impedance EI type, custom made with imported cores.
• Output transformer is larger imported core and 'perfect lay' windings.
• Speaker outputs: 0/4/8/16ohms
• non-magnetic chassis
• premium ceramic tube sockets and RCA connectors