Vacuum Tube Sound for the 21st CenturyMapletree 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.
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Preamplifiers | Routers and Switches | Power Amplifiers
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.
Below: Line 4CRM customer-specified balanced version of the Line 2CRM preamp/power supply. Photos show the finished units with birdseye maple side panels and copper-clad front facia, the preamp under listening test in Mapletree home system, and during construction. Preamp has Dueland RS coupling caps, Audio Note Tantalum film resistors, and Khozmo quad stepped attenuator. A balanced differential stage provides excellent common-mode rejection. A balanced cathode follower stage guarantees low output impedance with very low noise in either differential or single-ended output mode. Power supply is 100% over-rated with filtered ac input and EMI gaskets. Filter caps are Panasonic polypropylene. The only electrolytic cap in the whole system is in the dc heater supply.
Special: Line 2CRM line preamp with Alps/Bent Audio remote volume control and Auricap options together with PS 2C power supply. Finished in black with walnut side panels. Input gains are 5 dB/10dB/10 dB. Preamp features dual main outputs plus passive Record output. Ready to ship (input gains can be re-configured to customer specs and 240 VAC wiring is available at no extra cost). Includes NOS 12SN7GT tubes, power interconnect cable, IEC power cord, and remote handset. Priced with FREE Auricap option ($200 value) for $1000 USD. As an added bonus I can offer free shipping to N. American locations. This is a rare opportunity to own a classic preamp with the full-meal-deal treatment at a discount price.
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".
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
|Line 2C Line
of Line 2B SE by Tim Smith at wall of
Line 2CRM and PS 2C with
black oak side panels shown
components include polypropylene film coupling
capacitors and Alps
Line 2C RM
available with Bent Audio/Alps remote
Also availableLine 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
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 for 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 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 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 Al@mapletreeaudio.com.
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