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. 

Back to Main Page

Other Products

Power Amplifiers
Stealth Max Monobloc Power Amplifier - 50 W with KT88s running class AB1 ultra-linear with fixed bias. 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) and Dynaco spec output and power transformers. WIth 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 ( $30 additional).


               

                     
Download the User's Manual for detailed information.

Super Stealth monobloc power amplifier (kit and assembled). Using the new 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. Available as a kit or factory assembled.
• 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 level control for optimum sensitivity adjustment; input sensitivity 0.5 V.
• Compact chassis 7" x 12" x 6" overall.
More Information
Super Stealth kit manual

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. 

More Information
Installation Manual

Crossovers 


 The "Thingy" crossover and multi-channel driver.






Based on the concepts described in the Branches newsletter issue 4 , the MAD Thingy is in production. It features buffered high and low pass filters to implement a 500 Hz high-level crossover for driving multiple speaker systems or bi-amp aplications, plus  outputs for ambience and subwoofer channels. For more details, you can download the user's manual.

User comments.

Magic Eye Monitors

Eyes for your Ears! The Viper Magic Eye Monitor. Left and right channel levels are displayed by two 6E5C cathode ray tubes. Includes response speed and sensitivity controls with built in 12SC7 voltage amplifier stage.
More information.
New! Viper 4+ deluxe magic eye monitor and line router. Separate peak and average eye tubes for each channel with individual sensitivity controls. Internal voltage amplifier allows monitoring signals from line level sources, preamp outputs, or power amp outputs. Includes a 3-input, 3-output line router with selected input signal monitored. Router functions without power applied. Dimensions 12"  x 8". With 1629 cathode ray indicator tubes priced at $750 ($700 with Russian 6E5C tubes). Available for 240 VAC at no extra cost!

 Download the User's Manual for detailed information.


Line  Routers

LR 1 Line Router

• Any combination of 6 or less I/O lines is possible. Design it yourself to suit your needs.
• Ideal for switching line sources between headphone amplifier or preamp or adding additional line inputs to preamp.
• LR 1 Pro model features 3–2 switching with balanced I/O and XLR connectors.