Mapletree Audio Design Magic 5B SE Triplex Stereo Preamplifier

Three preamp topologies in one chassis

Proven, low-distortion octal tubes (3-12SN7GT, 2-6R7G/GT). Name-brand NOS types are supplied. Assembled unit can be configured for user-supplied 6SN7GT tubes.  Three complete preamp circuits are incorporated: a classic common cathode-cathode follower cascade (CF), a shunt-regulated push-pull (SRPP) circuit, and a passive path. Output and input switching permits any of three sources to be routed to either of the two active preamp circuits or through the passive path which allows use of the selector, volume, and individual channel level controls but with no amplification. A second set of output jacks is provided for bi-amplification or use with a separate headphone amplifier. DC heater supply. All wiring is point-to-point with silver-plated Teflon wire employed in all signal paths. Kit includes a punched, painted chassis, bottom cover plate, detachable line cord, all parts, tubes, hardware, wire, solder, fuses,  knobs. and a step-by-step instruction manual with separate wiring diagrams. Only a few standard tools and a soldering iron are necessary for construction.  High quality components are used throughout: carbon and metal film resistors, Auricap polypropylene film capacitors, Black Gate electrolytic capacitors, plastic element volume control, and Hammond and Tamura power transformers.

Specifications: Input resistance:  greater than 50K Ohms at 1 kHz. Output resistance: SRPP: OUT1 - 5.4 kW, OUT2 - 14KW,  CF: OUT1 - 660 W, OUT2 - 14KW, Passive: OUT1 - less than 25 kW at all volume settings, OUT2 – less than 20 kW. Voltage gain (100K load, OUT1): SRPP: 18 dB at 1 kHz, CF: 23 dB at 1 kHz, Passive: 0 dB at 1 kHz. Voltage gain (100K load, OUT2): SRPP: 8 dB at 1 kHz, CF: 13 dB at 1 kHz, Passive: -10 dB at 1 kHz.  Frequency response, 100K/50pF load): SRPP: 14Hz–60KHz (–0.5 dB), CF: 17Hz–20KHz (–0.5 dB), Passive (power off): dc–110KHz. Noise (100K load, OUT1):  SRPP/CF: < 0.2 mV,  Passive: < 0.1 mV.

Email enquiries to Lloyd Peppard at info@mapletreeaudio.com or phone (613) 387-3830