The David Berning Company

microZOTL 2.0   ... it's baaack - July, 2015

It's back. And more remarkable than ever. Newly configured, this micoZOTL amplifier utilizes David Berning's highly refined no-feedback Class A triode design coupled with his extremely sophisticated ZOTL power supply and impedance conversion circuitry. Currently in production, July, 2015


(original) microZOTL

a personal amplifier

AC / Battery Powered Tube Amp

manufactured from 2000 - 20007

The microZOTL is a new "personal amplifier" that is being introduced for the year 2000. This amplifier uses a 6SN7 tube as a push-pull, Class A output stage, and develops about 1 watt (4 ohms) for each channel. This amplifier was developed to showcase the patented Berning ZH OTL (output transformerless) impedance-conversion technology in a highly affordable product. While originally developed as a small high-quality amplifier for a bedroom or office, it is expected to find applications as a headphone amp (a headphone output is provided), a tweeter amp, or an amp than can adequately power a high-efficiency horn speaker. This amp has a 12-volt input for battery operation, as well as a built-in universal (100VAC-240VAC) input. The price is $750, direct sales only.

Specifications (Typical Performance Values)

  • Sensitivity: 0.6V RMS for full output.
  • Output impedance (measured at 0.5A, 60 Hz): 2 ohms.
  • Input impedance: 50k.
  • 100V / 120V / 240V operation: Auto-switching.
  • Hum and noise: 60mV RMS or 90dB below full output (20Hz-20kHz).
  • Carrier: -50dB (250kHz).
  • Current draw from 12V dc source: 2.1A.
  • Power consumption from ac power source: 33W.
  • Power output with 4-ohm load: 1W, 1% THD.
  • Power output with 14-ohm load: 0.5W, 1% THD.
  • Channel separation (4-ohm loads): 46dB, 100Hz-10kHz.
  • Channel separation (14-ohm loads): 54 dB, 100Hz-10kHz.
  • Frequency response (4-ohm load): +0, -1dB 10Hz-20kHz, full power.
  • Frequency response (14-ohm load): +0, -1dB 5Hz-50kHz, full power.
  • Amplifier class: Push-pull Class A, no feedback.
  • Voltage gain (4-ohm load): 10.3dB.
  • Voltage gain (14-ohm load): 12.4dB.
  • Size: 30.5cm (12 inches) wide, 11.5cm (4.5 inches) high, 14.6cm (5.75 inches) deep, not including connectors, controls and feet. Add 5cm to height and 3cm to depth for these.
  • Net weight: 1.8kg (4lb).
  • Finish: Aluminum case (colors: blue, red, dark olive-brown) with window.
  • Tube complement per channel: 12AT7 input, phase splitter, 6SN7 p-p output.
  • Price: US$ 750.00, direct sales only.
  • Level control and headphone jack included; battery and recharger not included.

Owners Manual PDF

microZOTL Reviews

A personal amplifier. 1 Watt. Line or battery powered. For driving headphones. ZOTL Technology.

microZOTL reviewed by Dick Olsher, enjoythemusic.com, October 2000

"There's undeniably a lot of magic in that little box. ... Just as a lark I plugged [headphones] into the Berning, and I almost fell out of my chair! All of a sudden, resolution and clarity galore! The ugly duckling was instantly transformed into a beautiful swan. Bass lines gained tremendous impact and precision. The midrange snapped into focus as though a thick veil had been lifted from the soundstage..."

microZOTL reviewed by Harvey "Dr. Gizmo" Rosenberg

"[microZOTL] is the best sounding headphone amp I have heard to date."

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