In Barn for Review: LTA Z40+ Integrated Amplifier

With the Z40+ Integrated Amplifier, Linear Tube Audio (LTA) promises—”beautiful tube tone with the clarity of solid state”—from 51 Watts (into 4 Ohms) of push-pull, class A/B output transformer-less ZOTL power per channel.

Being output transformer-less also means the Z40+ weighs a heck of lot less than similarly powerful transformer-endowed amps, which is music to my back. The new “+” version of the Z40 offers a number of upgrades including 100,000µF of additional capacitor storage, Audio Note resistors, Subwoofer Output, and an updated Volume Control w/ Adjustable Gain & “Hi-Res” Settings.

The review unit includes the optional MM/MC phono input which joins the RCA and XLR inputs, Tape Monitor (In/Out), Sub Out, IEC inlet, power switch, and single pair of Cardas speaker binding posts on the unit’s back side.

Four Gold Lion KT77s peak through the Z40+’s top plate (NOS Mullard EL34s are also available), while pairs of 12AU7s, 12AX7s, and 12AU7s hide inside.

the grid above the Headphone jacks lights up with the volume level when in use

A pair of headphone jacks (Hi/Lo) join the brass touch sensitive buttons on the Z40+ front panel. Fern & Roby designed the Z40+’s understatedly handsome chassis while David Berning’s patented ZOTL technology and preamp design reside within.

I was mightily impressed with the two LTA rooms at Axpona 2022 so I very much look forward to Barn time with the z40+.

Stay tuned!

LTA Z40+ Integrated Amplifier
Price: from $7650
Company Website: Linear Tube Audio


Inputs: 4 single-ended Cardas RCA stereo, 1 balanced input using two 3-pin XLRs
Speaker Output: 4 Cardas speaker binding posts
Headphone Outputs: Low: 220mW per channel @ 32 ohms, High: 2.6W per channel @ 32 ohms
Tape Monitor: 1 stereo tape monitor out, 1 stereo tape monitor in
Subwoofer Output: Stereo subwoofer output (Mono option available upon request)
Front Panel Controls: 7 brass touch switches (power, input, tape monitor, up, down, menu/select, back), volume control, and headphone speaker switch
Remote Control: All front panel functions using paired Apple TV Remote
Volume Control: 100 stepped attenuator (smallest step 1/1000th of total value) using Vishay Dale 1% precision resistors
Output impedance: 1.2 ohms
Input impedance: 47k
100V / 120V / 240V operation: Auto-switching
Hum and noise: 94dB below full output (measured at 20Hz-20kHz)
Power output with 4-ohm load: 51W, 0.5% THD
Power output with 8-ohm load: 46W, 0.5% THD
Frequency response (8-ohm load): 6Hz to 60kHz, +0, -.5dB
Amplifier class: Push-pull Class AB
Size: 17 inches wide, 5 1/8 inches tall, 18 inches deep (including connectors)
Net weight: Amplifier: 18 lbs./8.2 kg
Finish: Aluminum case
Tube complement: 2x 12AU7 preamp, 2x 12AX7, 2x 12AU7, 4x KT77
Home Theater Function can select any input for fixed volume
Display: 16 Levels of brightness and programmable 7-second time out
MM/MC Phono Stage:

Inputs: MM or MC
MM Gain: 46 db fixed
MC gain: 10db/20db additional (56 db total or 66 db. selectable by jumpers)
MM loading: 47K ohms
MC loading: 10, 20, 30, 50, 100, 200, 470 ohms selectable by dipswitch
100pf, 220pf, 330pf selectable by dipswitch