microZOTL Preamplifier


microZOTL Preamplifier


The ultimate expression of the microZOTL as a full-featured reference preamplifier and headphone amplifier.

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“Across every sonic attribute: timbres/color, image palpability/density, spatial qualities- air around players- tremendous soundstage depth/width/height, powerful overall dynamics, and deep extension with great low frequencies regarding tone/accuracy which gives a great foundation to the music.  All this and delivered with total liquidity and ease.  This preamplifier renders the illusion of real music better then any other linestage I have had in-house for review.”

- Teajay, Audiogon


Home Theater Review

After years of refining and testing the microZOTL circuit, LTA has created the microZOTL Preamplifier. This is the highest expression of the amp as both preamp and headphone amp. In a beautiful new, low-resonance chassis designed by Fern & Roby featuring Cardas connectors, the microZOTL preamp contains all of the elements that we found improved the sound significantly.

A digital interface gives control (via the remote or the brass capacitive buttons on the faceplate) over the new stepped attenuator volume control and improved input wiring that greatly shortens the signal path. The power supply is larger and more refined, and there are several integral component upgrades in the audio circuit. We now use ceramic circuit boards, which result in the clearest, cleanest sounding microZOTL yet.

“I’m running the new preamp (S/N 005) with my XA30.8. The combination is flat out beautiful. I also have an MZ2 which worked well, but the new pre is just better in every way. Clarity, staging, dynamics (both micro and macro). Very liquid, fatigue free, but also dynamic and extended.

“. . . the beautiful chassis, the ergonomics, and that sound, rich organic timbres/colors, a sense of “aliveness” that I find in no other preamplifier, the smallest details easily heard, a spatial perspective that brings the musicians into your acoustic space, a sense of holographic imaging, and an effortless liquidity that lets the music “spill” into your room.

“. . . micro-details were clearer and were easier to hear all delivered with an overall liquidity and effortlessness that let the music flow into my room.

“. . . the MicroZOTL Preamplifier produced a spatial perspective that made my seven foot tall 21 driver speakers completely vanish in the largest and accurately layered soundstage that I have ever experienced in my listening room.”

-Greg, Audiogon


Inputs: 4 Stereo RCA single ended inputs using high quality Cardas connectors and 1 XLR unbalanced single ended input. Sealed, silver contact relays utilized in a short signal path. One additional Tape input.

Outputs: Headphone ¼” Phone jack, dual Cardas RCA single ended preamplifier outputs, and a Tape Monitor output utilizing Cardas RCAs (input level before volume control).

Amplifier class: Push-pull Class A, no feedback

Sensitivity: 0.6V RMS [full output]

Output impedance: (measured @ 0.5A, 60 Hz) 2 ohms for headphone outputs, 50 ohms for preamplifier outputs

Input impedance: 50k

Volume Control: Stepped attenuator constructed of 1025 steps of 50 ohms, with 100 positions selected to provide very fine resolution at the lowest volumes and a logarithmic control for higher volumes . Low noise, precision 1% Vishay Dale resistors and hermetically sealed silver contact relays are used for precise, isolated analog signal attenuation

Balance Control: 100% channel isolation using stored differences of volume values. Maximum balance differential is 16 steps

Power Supply: Linear supply user-switchable between 110/120 and 220/240 (100V linear supply available for Japan). Uses dual banks of organic poly ultra low ESR capacitors (4 times MZ2) and premium Nichicon electrolytic for over 100Kuf of output choke isolated storage. Oversize transformer secured with aluminum and brass mountings (no steel). Regulation is performed using low noise Belleson super regulators. Current transformer controls output protection circuit

Hum and noise: minimum 60mV RMS or 90dB below full output (20Hz-20kHz)

Power consumption from ac power source: approx. 50W

Power output: with 4-ohm load: 1W, 1% THD, with 14-ohm load: 0.5W, 1% THD

Channel separation: (4-ohm loads) 46dB, 100Hz-10kHz, (14-ohm loads): 54 dB, 100Hz-10kHz

Frequency response full power: (4-ohm load) +0, -1dB 10Hz-20kHz, (14-ohm load): +0, -1dB 5Hz-50kHz,

Voltage gain: (4-ohm load): 10.3dB, (14-ohm load): 12.4dB

Front Panel Control: Functions include volume, input select, headphone/speaker output select, all configuration menu selections, and amplifier power on-off. Capacitive brass touch buttons are utilized for menu control, input selection, tape monitor control and power on-off.

Remote Control: All functions, including Mute and the configuration menu, are available from the remote, except power on-off.  Uses an Apple TV remote.  The remote is registered to unit to limit control from unintended remotes. The Right-Left buttons can be configured as balance controls.

Auto-save Features: Volume level per input is automatically saved and the unit powers on using the stored volume levels. Balance and all other configuration menu selections are all saved as a global level across all inputs.

Display Controls: 16 levels of brightness and on-off selectable 7 second timeout

Home Theater Mode: an input can be selected from configuration menu to set one of the inputs to a high-volume level fixed input to allow surround sound device control the volume level

Front Panel Power Switch Override: power switch on front panel can be configured to be set to always on to allow external on-off control for device such as remote-controlled power conditioner

Tube complement: 2 premium hand selected 12AT7 input tubes, and two premium hand selected 12SN7 output tubes.  (6SN7s can be used with jumper settings) 12AU7s are often substituted for the 12AT7s to lower the gain if higher headphone output is not required.  

Size: 17 inches (43.2 cm) wide, 4.2 inches (10.7 cm) tall, 12.4 inches (31.5 cm) deep (including knob and connectors)

Net weight: 14 lbs. (6.35 kg.) Shipping weight: 22 lbs. (10 kg)