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. 

Click on these tubes for more information ^^^^^^^^^^

Quick Find:    Headphone Amplifiers   |   Preamplifiers  |   Other Products (line routers, Dynaco driver board, power amplifiers)

Customer Photos of the Month: 

Mapletree Audio Super Stealth + monoblocs with Ultra 4C phono/line preamp and PS 2C power supply
. Lenco turntable is modified by Jean Nantais. Speakers are Tannoy Ardens. Super Stealth stands (behing the speakers) are made from a salvaged solid oak desk.


Mapletree Audio Ear+ HD custom implementation with source selection and purpleheart side panels.


The Mapletree Engineered To Order (ETO) concept: The SP 1 and the new SCC 1 System Configuration Controller

Customers often have specific requirements that can be met with custom features and/or 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 SP 1 Amplifier/Speaker Switch and the new SCC 1 (System Configuration Controller) are designed for customization. The SP 1 below can switch three amplifiers to three speaker systems with any two speakers systems connected at the same time.

Below is an "all in one" SCC 1 customized for switching 3 sources, 2 preamps, 2 power amps, and 3 speaker systems. Includes an output for a headphone amp and a mute position.

"[The SCC 1 is] simple elegant and effective. Does exactly what I needed it to do and has significantly reduced the effort involved in switching between components. Just a wonderful product".

NEW! Wood side panels are now available in a variety of cabinet woods to match your other system components or personal preference.

The photos of the Mapletree products shown on this web site have side panels finished in both aluminum and wood. Recently, many customers have specified wood panels in maple or oak and these have been supplied at no extra cost.. In association with a local woodworker/luthier, wood side panels are now available in walnut, butternut, and cherry at $20 additional cost. Oak (including black oak) and maple are also available at no extra cost. Examples are shown below on a black chassis. 

left to right: walnut, butternut, and cherry



A comparison of the Mapletree/SugarMaple headphone amplifiers

Ear+ HD Headphone Amplifier ---- still the gold standard after 15 years

"Now I have to listen to all my CDs all over again. I have a decent stereo system but with the Ear+ it sounds like a $20,000 setup".

Reviews Customer feedback

• Outstanding performance with a wide range of headphone impedances and drive requirements.
• 2 x 12B4A NOS and 1 x 5751/12AX7/ECC83 tubes.
• High and low impedance headhone jacks.
• Premium passive components include Panasonic polypropylene output capacitors and Alps volume control.
• Ultra high-speed rectifier diodes.
• Line source output or passive preamp output.
• Dual switched source inputs.

• Available with red/black/white/yellow/blue/green chassis top with anodized aluminum side panels.
• Dimensions: 6" x 10" footprint x 5" tall
• Weight: 8 lb


SugarMaple OD300 Headphone Amplifier

This is the first product developed by Mapletree Audio Design Associate, Dr. Al Freundorfer, under the new SugarMaple banner. The OD300 (Octal Duo) Headphone Amplifier employs an all-octal tube lineup including a 6080 (6AS7G equivalent) output and a 6SL7GT triode driver stage. Polypropylene output caps are standard and circuit refinements ensure a perfectly flat frequency response from 20 Hz to 20000 kHz. The high output power (over 1 W into 16 Ohms!) and low driving impedance of the 6AS7G easily handle any headphone sensitivity and impedance characteristic. For more details and complete specifications, you can download the User's Manual.
"The OD300 sounds great after settling in and combines musical dynamism with a lovely euphonic quality."

Latest custom review of the SugarMaple OD300.

SugarMaple Sidewinder Headphone Amplifier

NEW! Customer feedback on the SugarMaple Sidewinder.

The latest take on the Ear+ HD theme features ultra-low output impedance and ample opportunity for tube rolling with new and NOS 6DJ8 and 12AX7 tubes and variants. For more details, download the User's Manual.

  A comparison of the Mapletree/SugarMaple headphone amplifiers


Line 2C Line Preamplifier                  Review of Line 2B SE by Tim Smith at wall of sound.

Customer feedback

Line 2C and PS 2C with maple side panels shown

• Premium passive components include polypropylene film coupling capacitors and Alps volume control.
• Optimized circuitry for lowest distortion and noise.
• 3 inputs, 2 outputs, volume and balance control.
• 2 x 12SN7GT with switch for 6SN7GT tubes.
• Separate PS 2C power supply (with tube/fast diode hybrid rectification) included.

- Line 2C RM now available with Bent Audio/Alps remote volume control.  

Also available—Line 2C HT with Home Theater bypass. The source input switch is modified to select Line1, Line2, or HT. In HT mode, Line2 (front channels) is routed to the output completely isolated from the preamp circuitry (preamp can be powered off).


Ultra 4C Phono/Line Preamplifier

Customer feedback

Ultra 4C and PS 2C with optional butternut side panels shown

• Premium passive components include polypropylene film coupling capacitors and Alps volume control.
 • 48 dB phono gain, three 18 dB line inputs, two line outputs.
• Volume and Balance controls.
• 2 x 12SN7GT (switchable fo
r 6SN7GT) and 2 x 12SC7.
• Separate PS 2C power supply included (tube/hybrid rectification with 6X4 tube; chassis size to match preamp).

- Ultra 4C RM now available with Bent Audio/Alps remote volume control.

 Phono 3C Phono Preamplifier


NOTE: The Phono 3 is normally supplied with wood side panels as shown for other preamps

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 b
uffer 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

New layout to facilitate tube rolling.


 Sweeten the sonics of your DAC or other digital source with the Black Buff  line stage. It features unity gain, 50K 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). Download the User's Manual  for complete specs. email inquiries on this product to


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
(613) 387-3830

Lloyd Peppard
Mapletree Audio Design
158 Seabrooke Rd
R.R. 1, Seeley's Bay, Ontario, Canada K0H 2N0

Al Freundorfer
SugarMaple product line

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