Vacuum Tube Sound for the 21st CenturyMapletree 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.
Click on these tubes for more information ^^^^^^^^^^
Preamplifiers | Other Products (line routers,
Dynaco driver board, power amplifiers)
New! SUPER STEALTH + Monobloc Power Amplifier with 20 Free Watts!*
* The Super Stealth + monobloc power amplifier features the same proven Mullard circuitry as the 10 W Super Stealth but offers 30 W power output using EL34 tubes with uprated power supply and output transformers--all for the same price as the Super Stealth (introductory offer).
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 Hz20 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)
The Mapletree Engineered To Order (ETO) Concept
Customers often have specific requirements that can be met with custom features and modifications to existing Mapletree products. Usually, these can be accommodated at nominal extra cost. Let us know if ETO can tailor a product to the particular needs of your system. The LR 1 shown on the left has custom features that were implemented at no extra cost. The L2X preamp with PSX power supply (right) is a compact derivative of the Line 2C/PS2C with customizable features including maximum gain (unit shown is configured as a unity gain buffer), level control, heater voltage switch, second input, etc. Base price (single I/O, level control, heater voltage switch) with PSX power supply is $670.
|Free shipping expanded
and extended: Free
Expedited Mail delivery of Ear+ HD, Super
II, Line 2C, Phono 3C, Ultra 4C, and
LR 1/SP 1 orders to N. American locations
during Juanuary, 2016. A shipping discount is
applicable for international orders.
|Line 2C Line
of Line 2B SE by Tim Smith at wall of
- Line 2C RM now
available with Bent Audio/Alps remote
volume control -
Ultra 4C Phono/Line Preamplifier
Premium passive components include polypropylene film coupling capacitors and Alps volume control.
48 dB phono gain, three 18 dB line inputs, two line outputs, rec output.
Volume and Balance controls.
2 x 12SN7GT (switchable for 6SN7GT) and 2 x 12SC7.
Separate PS 2C power supply included.
- Ultra 4C RM now available with Bent Audio/Alps remote volume control -
PS 2C Power Supply Supplied with Line 2C, Line 2C RM, Ultra 4C, and Ultra 4C RM
Newest version of the PS 2 power supply uses a 6X4/EZ90 rectifier tube in place of the 6X5GT of the PS 2. The latter tube is getting harder to source and has a reputation for premature failure due to shorts (not experienced with the PS 2 but definitely a weakness). The 6X4 is easier to source and the equivalent EZ90 is currently manufactured. The tube is enclosed in the PS 2C chassis as are the filter capacitors. Specifications are unchanged.
Phono 3C Phono Preamplifier
For a number of years, customers have asked about a phono preamplifier that embodies just the phono stage of the Ultra 4. The issue was always that the Ultra 4 was really a phono preamp with line inputs, so there was little price or sonic advantage in going to a dedicated phono version of the Ultra 4 by omitting the volume/balance controls and source selector switch. The phono gain of the Ultra 4 is around 48 dB which is suitable for MM cartridges driving a typical tube or solid-state power amplifier. The new Phono 3 preamplifier incorporates the low-level gain and equalization stages of the Ultra 4 without the output buffer and with around 10 dB less gain. Thus, it is suited to drive the line input of a preamp or integrated amplifier with at least 5-10 dB of additional gain. The Phono 3 output has a driving impedance of around 2.5 kOhms, which can drive a reasonable length of interconnect without compromising the high frequency response. Noise at full output is less than 2 mV. Like the other Mapletree preamps, the Phono 3 is designed to use a separate power supply. Normally, for stand-alone use, this is the compact PSX unit shown. However, the Phono 3 is fitted with an extra power jack on the rear panel to permit connection of the PS 2 power supply to both the Phono 3 and Line 2 preamps without any modification. Two switched phono inputs are provided, which can be ordered with custom loading specs. A power switch on the rear panel allows powering down the Phono 3 when just the Line 2 preamp is needed in a shared power supply setup. Details and full specifications can be viewed by downloading the User's Manual from the "Users Manuals" page.
SugarMaple BB (Black Buff) Line Level Buffer Stage
You can now sweeten the sonics of your DAC or other digital source with the Black Buff line stage. It features unity gain, 100K input impedance, <500 Ohms output impedance, and includes a volume control and heater voltage switch for use of either a 6SN7GT or 12SN7GT tube (supplied). Tube heater glow is visible through opening in chassis. Download the User's Manual for complete specs.
Dr. P spins some 78s on his mini system. Photo by Christian Keresztes
For more information or to place an order, please telephone or email Lloyd Peppard at