Linear Tube Audio MZ3 User manual

USER GUIDE: MZ3
Linear Tube Audio Takoma Park, MD, USA
301-448-1534 [email protected]
WARNING: For safety, the cover of this amplifier should be secured
at all times.
This amplifier contains extremely high voltages and the user should
not attempt to service the amplifier. Furthermore, this amplifier
generates radio-frequency energy that can interfere with
communications equipment.
Introduction
The MZ3 is a Class A tube amplifier utilizing ZOTL (Zero-hysteresis
Output Transformer-Less) technology. The MZ3 represents several
years of research and listening in order to significantly improve on
both the original micro-ZOTL designed by David Berning in 1999
and the MicroZOTL2.0 (now the MZ2) released by LTA in 2015.

Limited Two-Year Warranty*
1. Your new product is covered by a limited two-year warranty
against defects in material and workmanship. Any repairs
required will be made at no charge within the first two years after
purchase as a new unit.
2. Any units returned for warranty repair must be shipped prepaid
after receiving return authorization. If possible, the unit should be
shipped in its original packaging. If this is not possible, the unit
should be well packed with particular attention paid to protection
of all corners and avoidance of any looseness in the carton.
3. This warranty does not apply to damage resulting from physical
abuse or unauthorized alterations or repairs, or from tube rolling or
adapter use, or from the use of third-party components, or
damage to exterior finish resulting from careless use.
4. The warranty is void if the serial number has been removed,
altered, or defaced.
5. This warranty is void if improper voltage is applied to any input or
output.
6. If Linear Tube Audio determines after receiving the unit that
damage was misrepresented and has been caused by something
not covered by the warranty, the customer must pay for any
necessary repairs before the unit is returned to the customer.
7. Linear Tube Audio reserves the right to improve or change its
products without obligation to modify previously manufactured
units.
* Applicable for domestic sales only. There is a one year warranty
for overseas customers. Handling and shipping costs are the
responsibility of the overseas customer.
Service Note
ZOTL amplifiers use a unique circuit and even trained technicians
familiar with tube amplifiers may not know how to correctly work
on LTA products. Please contact us before attempting any
alteration or repair, whether you are concerned about the
warranty or not.!

Specifications
Circuit Type: Push-Pull Class A
Power Output: 1W (4 Ohm), 0.5W (8 Ohm)
Input Sensitivity: 0.6V RMS for full output
Input Impedance: 50K
Output impedance: 2 Ohms (measured at 0.5A, 60 Hz)
Preamp Output Impedance: 50 Ohms
Gain: 10.3dB (4 Ohm load)
12.4dB (8 Ohm load)"
Noise: -90dB
Frequency Response: +/- 1dB, 10Hz-20kHz (4 Ohm Load)
+/- 1dB, 5Hz-50kHz (8 Ohm Load)
THD: 1%
Power consumption: 33W"
Input Voltage: 110/220 Selectable
Tube Complement: (2x) 12AT7, (2x) 6SN7/12SN7
Size: Amplifier: W: 10” (25.5cm), H: 4.75: (12cm), D: 8.5” (18cm)
PSU: W: 5.25” (13.5cm) H: 4.25” (11cm) D: 12.25” (31cm)
Weight: Amplifier: 7 lbs (3.2 kg),
PSU: 5.2 lbs (2.35kg)
Shipping Weight: 17 lbs (7.7kg)

Quick Start
Remove amplifier, power supply, and included cables from the
box.
Attach the DC umbilical cable to the power supply and amplifier.
This has a 4-pin XLR on each side - make sure these are securely
attached.
Attach the power cable to the IEC connector on the power
supply, and plug into an outlet.
Hook up your sources as well as your power amp, if using the MZ3
as a preamp.
Once your system is set up and everything is hooked up, turn on
your system.
Operation
The unit is designed to be powered on indefinitely without harm.
You can also safely leave only the power supply on, using the
power button on the front panel to turn the amplifier on and off.
While it does not generate much heat, the unit is air cooled and
should be placed somewhere with adequate ventilation.
There are 3 RCA pairs on the back for 3 inputs, selectable via
toggle switch on the front panel.
The 2 RCA pairs next to the speaker binding posts are for the
preamp output. While the headphone and speaker outputs are
identical, the preamp output is optimized for preamp use and has
a higher output impedance. Both preamp outputs are identical.
The binding posts for the speakers can be used with banana plugs,
spades, and bare wire. We recommend using very sensitive
speakers (at least 98dB) if you want to utilize the MZ2 as a speaker
amplifier.

!

User Interface and Controls
The front panel features a power switch, input switch, volume
knob, and display. The remote control is able to adjust volume,
mute, and access a menu with more configurable options.
Remote Control
Up and Down Buttons: These normally function as Volume Up and
Volume Down. They can be held down or used in a single step
mode. In Menu mode, they function to move up and down in the
menu as displayed on the operator display.
Left and Right Buttons: In normal operation these are not active.
They can be configured in the “L-R Remote Arrows” Menu to
function as the Balance control. In the Menu mode, they act as
selectors.
Center Button: This normally functions as a Mute function. When
the unit is muted, there are two Xs on the display. When in Menu
Mode, the Center button functions as a Select button.
Menu Button: When in normal operation, selects the Menu Mode.
In the menu, this functions as a Select button.
Play/Pause Button: This is only used to pair a new Apple remote to
the unit, which is done by holding the button down for 30 seconds.

Menu
The menu is accessed via the Menu button on the remote control.
Scroll with the up and down buttons to see menu options. Pause
on an option to see the entire title scroll by.
Balance: Use the right and left remote buttons to adjust the
balance. The front panel displays the balance setting as you
adjust - two bars in the center indicate that the balance is at 0
(both channels are equal). Press the center button to save the
setting. The display will indicate which setting the balance has
been set to. The balance setting is saved across all inputs. The
maximum balance setting is 16 levels difference.
Brightness: The front panel display can be set to 16 levels of
brightness. The brightness levels are saved and recalled upon
power on.
Display Timeout: The volume display and input LEDs can be set to
turn off after 10 seconds. They will reappear if a button on the
remote control is pressed or the volume knob or front panel switch
is changed. There are 3 settings:
OFF - The volume display and input LEDs remain on.
VOL - The volume display turns off but the input LEDs remain on.
ALL - The volume display and input LEDs turn off.
L-R Remote Arrows: There are two functions that can be selected
for the Left-Right Arrow buttons as follows:
Off – the remote Left-Right arrow buttons are deactivated.
BAL – the remote Left-Right arrow buttons will control the balance.
Power-On Override: When activated, the unit powers on when the
AC power is turned on without needing push the front panel
power button.
Reset to Default: The amplifier controls are set to Balance = 0,
Display Timeout = Off, Home Theater Mode = None, and Display
Brightness = 8, and Remote Left-Right Arrow buttons set to Not
Active.

Tube Heater Voltage Jumper Settings
The MZ3 comes with selected
old-stock 12SN7 tubes as its
standard output tubes. By
changing the jumpers on the
circuit board, the amp can also
use 6SN7 tubes. These are
identical sonically, they simply
use different voltages for the
heater. When switching from
one to the other, be sure to set
the jumpers on the boards to
the correct position. A 6-volt
tube like the 6SN7 will burn out
quickly if given 12 volts.
On the circuit board, there are
two headers next to each other,
for a total of 4 pins. There is a small diagram showing the correct
way to orient the jumpers. When using only a single jumper in 6V
operation, there is a header labeled “park” where you can store
the extra jumper.
To use 6SN7s, set the jumpers to 6V by placing a single jumper
across the center two pins. To use 12SN7s, set the jumpers to 12V
by using two jumpers, covering all 4 pins.
Tube Replacement/Rolling: The amplifier operates the tubes in a
manner that maximize tube life and the tubes are expected to last
over 10 years of regular use. The sockets are tight, so gently rock
the tube pins until you are able to remove the tubes. We use high-
quality ceramic tube sockets with gold pins which are designed in
such a way that the white ceramic part may shift slightly. This is an
intentional design; the tube socket is very secure.

We have heard no reports of any trouble using equivalents of
6SN7, 12SN7, or 12AT7 tubes. For lower gain and a more laid-back
sound, you can substitute 12AU7 tubes for the 12AT7s. Do not use
12AX7s. When replacing the tubes, use matched pairs.
Fuses: The MZ3 has a fuse on the audio board and two fuses in the
LPS+. All are 5x20mm. There is a 2.5A Fast Blow fuse on the audio
board there are two 4A Slow Blow fuses in the IEC inlet of the
Power Supply.
For more information and FAQs, please visit
www.lineartubeaudio.com or contact us at
[email protected].

NOTES