Vacuum Tube Sound for the 21st Century

Mapletree Audio Design offers a unique range of products designed and hand crafted by Dr. Lloyd Peppard and Dr. Al Freundorfer, both electrical engineering professors, Our goal is to foster the enjoyment of recorded music through the use of vacuum tube amplification and signal processing, offered at a reasoble price. 

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

Quick Find:    Headphone Amplifiers   |   Preamplifiers  |   Routers and Switches  Power Amplifiers

NOTICE: Due to circumstances beyond my control, I will not be able to take new MapleTree orders until May, 2018. If you are interested in the SugarMaple products, custom switch boxes, etc., designed and built by Dr. Al Freundorfer, you can email him at  

Lloyd Peppard

Special SOLD

I have completed an Ear+ HD headphone amp with tiger maple sides and trim (below). Price is $ 790 USD and I will ship it free to N. American locations.



Engineered To Order (ETO)

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. The most modifiable components are those disigned to route signals and/or reconfigure system components, namely the LR 1 Line Router, the SP 1 Amplifier/Speaker Selector, and the SCC 1 System Configuration Controller. Here is a brief summary of what is available. More information can be obtained from the Branches 7 Newsletter.

LR 1 Line Router - The standard version is designed to switch one of up to three input stereo signals to one of up to three outputs. Other configurations are available to handle up to 6 inputs and/or outputs. Chassis sizes are chosen to accommodate the required I/O connections. As with all the Mapletree switching components, RCA jacks are high quality gold plated with inside and outside hex nuts, switches are Lorlin or C&K enclosed rotary types with silver-plated contacts, and wiring is silver-plated stranded copper with Teflon insulation.

Custom LR 1 for phono cartridge switching (4 inputs/2 outputs)

LR 1 Pro Line Router -
This is a balanced signal version of the LR 1. The standard model can switch up to  3 inputs and 3 outputs. Additional I/O can be accommodated using special multi-deck rotary switches. XLR connectors are Neutrik gold-plated type with locking tabs on the female version.

Custom LR 1 Pro with 4 inputs and one output.             

"I received the switch [LR 1 Pro] today and it is exactly what I wanted and works perfectly - no noise at all when switching. I have bypassed my preamp for my DAC and LPs and have a sonic improvement".

SP 1 Amplifier/Speaker Selector
- The simplest (standard) version switches the stereo output of a power amplifier to one of two (or both) speaker systems. A typical modification is the addition of a switch for one or more amplifier outputs. All switches handling amplifier output or speaker connections are high-current rated versions of those employed in the LR 1 line router
  All amplifier inputs are terminated with 500 Ohm resistors and binding posts are heavy-duty 5-way dual units. A simplified schematic representation of the I/O and switching functions as printed on the top of the chassis.

Custom SP 1 switching 3 amplifiers to one or more of 3 speaker systems

SCC 1 System Configuration Controller - This is a custom combination of the LR 1 and SP 1 that allows switching of several sources to one or more preamps or headphone amplifier, preamp outputs to one or more power amplifier inputs, and power amplifier outputs to one or more speaker systems. 

"[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".

Custom SCC 1 that handles 3 sources, two preamps, a headphone amplifier, 2 power amplifiers, and 3 speaker systems. Chassis ia 6" x 17" x 3".

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 a variety of woods. Maple or oak (including black oak) are the standard no-cost options.. In association with a local woodworker/luthier, wood side panels are now available in walnut, butternut, and cherry at $20 additional 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 maple or oak 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 2CRM and PS 2C with black oak 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 available with Bent Audio/Alps remote volume control.  

Also available—Line 2C HT with Home Theatre 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 available with Bent Audio/Alps remote volume control.

 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 3C preamplifier incorporates the low-level gain and equalization stages of the Ultra 4C 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  3C 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 3C is designed to use a separate power supply. Normally, for stand-alone use, this is the compact PSX unit shown. However, the Phono 3C can be fitted with an extra power jack on the rear panel to permit connection of the PS 2C power supply to both the Phono 3C and Line 2C preamps without any modification. Two switched phono inputs are provided, which can be ordered with custom loading specs. 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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