ZOTL40 Reference Amplifier


ZOTL40 Reference Amplifier


The ZOTL40 Reference amplifier provides 40+ watts per channel output with accurate, uncolored sound and automatically protected circuitry. The ZOTL40 Reference sets itself apart from its peers, producing an unforgettably palpable and poignant listening experience.

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Linear Tube Audio is proud to present the ZOTL40 Reference amplifier. A worthy flagship and the most refined manifestation of David Berning’s ZOTL design.

The latest iteration of LTA's EL34-based amplifier, the ZOTL40 Reference includes a new chassis, component improvements, and is supplied with Mullard NOS EL-34s that take this 40-50 watt-per-channel amp to a new level.

What’s New in the ZOTL40 Reference Amplifier

We have been making the ZOTL40 (Mk II) for a couple years, and it enjoys a stellar reputation when using low sensitivity speakers such as electrostatics. Over the past year LTA has invested in design development and along the way found opportunities to bring fresh insights and refinements into every one of the products in our lineup, including the ZOTL40 reference power amplifier.

The ZOTL40 reference amp is the kind of unbelievably good product that can only be developed with careful experimentation over time.

Improvements in the ZOTL40 Reference amplifier include:

  • Careful component auditioning (review & final selection) with a broad range of available loudspeakers to elevate the ZOTL40 reference amp to deliver the best results possible for our clientele.

  • Premium Mullard EL-34 tubes are standard.

  • New chassis designed and built by Fern & Roby includes careful selection of materials and finishes plus grounding and shielding improvements.

The result is a significant improvement to the ZOTL40 Mk II that makes the ZOTL40 Reference an end-game component for guaranteed excellence in any presentation.

Purchase without fear or doubt. Like all Linear Tube Audio products, the ZOTL40 Reference Amplifier comes with a 14-day no-questions-asked return period and a one-year warranty.


Sensitivity: 1.2V provides full output

Output impedance: 1.6 ohms

Input impedance: 50k

100V / 120V / 240V operation: Auto-switching

Hum and noise: 94dB below full output (measured between 8Hz-60kHz +0/-0.5dB)

Power output with 4-ohm load: up to 51W, 0.5% THD

Power output with 8-ohm load: up to 46W, 0.5% THD

Frequency response (8-ohm load): 8Hz to 50kHz, +0, -.5dB

Amplifier class: Push-pull Class AB

Net weight: 15 lbs

Finish: Aluminum case

Tube complement: two 12AX7s, two 12AU7s, & four Mullard NOS EL-34s

Push-pull, Class AB output stage

No adjustments – tubes are auto-biased