Vacuum Tube Sound for the 21st Century

Mapletree Audio Design offers a unique range of products designed and hand crafted by Dr. Lloyd Peppard, a retired electronics engineering professor. The goal is to increase your enjoyment of recorded music through the use of vacuum tube amplification and signal processing. 

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Other Products (download User's Manuals from home page or contact Mapletree Audio for more information)

Power Amplifiers

Stealth Max Monobloc Power Amplifier

Delivers 50 W with KT88s running class AB1 ultra-linear with fixed bias. Includes a triode mode switch. Built on a stainless steel Dynaco Mk III chassis  with Mullard  topology driver circuitry (6SJ7 voltage amplifier and 6SN7GT long-tail phase inverter), Dynaco spec output and power transformers., premium passive components, and a very stiff power supply, the sonics are effortless and open, espeicially noticable on high level transients. Available for 240 VAC ( $50 additional).


Stealth Max system with custom passive stereo attenuator for use without active preamp

Super Stealth Monobloc Power Amplifier

Using the EH 6V6GT tubes in class AB ultra-linear push-pull, the Super Stealth delivers a clean 8 W, making it suitable for a wide range of speaker systems.

• 20-20 kHz -1 dB at 5W
• Mullard topology driver circuitry using 12SJ7 pentode and 12SC7 cathode-coupled phase inverter.
• Supplied with EH 6V6GT matched pair output tubes.
• Quiet, ultra high speed diode power supply and DC heater supply for all tubes.
• Ultra-low output noise–less than 025 mV (90 dB below rated output) makes it suitable for high-efficiency speaker systems.
• Input sensitivity 0.5 V.
• Compact chassis 7" x 12" x 6" overall.

Note: Front handle and input level control are not included.

Super Stealth SE
Monobloc Power Amplifier

The special edition of the Super Stealth includes input level control, heater switch for 12 V or 6 V driver tubes, dc balance adjustment for output tubes, and bias adjustment. 

Super Stealth + Monobloc Power Amplifier

 The Super Stealth + monobloc power amplifier features the same proven Mullard circuitry as the Super Stealth but offers 30 W power output using EL34 tubes with uprated power supply and output transformers. Please note that the styling is not as shown. Black chassis are fitted with wood side panels to match other Mapletree products.


Tube complement: 12SJ7/12SJ7GT, 12SC7, 2 x EL34 matched pair
Rectifier: full-wave solid state with ultra high-speed silicon diodes
Output configuration: Class AB1 ultra-linear push-pull with self bias (EL34 matched pair
Driver circuit topology: Mullard type with pentode voltage amplifier (12SJ7) and
cathode-coupled phase inverter (12SN7)
Rated power output (8 Ohms): 30 W
Frequency response at 1 W output: 20 Hz–20 kHz –0.5 dB
Gain: 27 dB (22.2) or 0.7 V input for 30 W output
Input resistance: 100 kOhms with input level control
Output resistance: < 1 Ohm
Noise: < 0.7 mV (87 dB below rated output)
Dimensions: 6"W x 11" D x 6" H overall
Weight: 15 lb

User's Manual download (pdf)

Special Red octal driver module for Dynaco Stereo 70 power amplifiers. A drop in, point-to-pointwired driver board using Mullard driver topology with 2-6SJ7 and 2-6SL7GT tubes.