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microZOTL 3 by Linear Tube Audio. True High End Audio.

Discussion in 'Headphone Amps (full-size)' started by jamato8, Dec 21, 2018.
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  1. jamato8 Contributor

    I have had the MZ2 that I modified with wiring, etc., but the topology is the same as stock. The MZ3 has some real changes and I love the looks of the case. This should be a very worthwhile listen. Remember the 12SN7 is a bargain of a tube and quieter than it identical, though lower filament voltage, 6SN7. Good Stuff!

    The MZ3 also uses a ceramic board! Can't get much better than that.

    User Manual. Here



    Information copied from Linear Tube Audio's web page:

    The microZOTL MZ3 represents the evolution of the microZOTL technology as a headphone amplifier, a preamplifier, and a 1 watt speaker amplifier in the external power supply form factor of the MZ2.

    Incorporating almost all of the technology enhancements recently released in our new microZOTL Preamplifier, the microZOTL MZ3 is the result of years of refining the microZOTL circuitry. This is the highest expression of the amp as a preamp, headphone amp, and 1 watt speaker amp. In a beautiful new, low-resonance aluminum chassis designed by Fern & Roby, the microZOTL MZ3 contains all of the elements that we found improved the sound significantly.

    A digital interface features an LED array display for volume and input, a new remote-controlled stepped attenuator volume control, and improved input wiring that greatly shortens the signal path. The power supply is larger and more refined, with a premium interconnect cable, and no more turn on thumps. There are several integral component upgrades in the audio circuit for wider soundstage, lower noise floor, and improved musicality. We now use ceramic circuit boards for the amplifier, which result in the clearest, cleanest sounding microZOTL yet.

    We curate premium tubes for you to ensure you experience the amplifiers’ maximum performance right out of the box.


    Inputs: 3 Stereo single ended RCA high quality connectors using sealed, silver contact relay control for a short signal path

    Headphone ¼” Phone jack, Dual preamp RCA outputs single ended, Stereo speaker binding posts

    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 and speaker 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) 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

    Power Supply Output:
    12VDC 3 amps

    Power Supply Umbilical Cable:
    premium low noise shielded cable with silver contact, spring loaded premium XLR connectors

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

    Power consumption from ac power source:

    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, and amplifier power on-off.

    Remote Control:
    All functions, including Mute and the configuration menu, are available from the remote, except power on-off and headphone/speaker output selection. 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

    amp: 9 1/2 inches (24.1 cm)wide, 4 3/4 inches (12.0 cm) tall, 7 7/8 inches (19.7 cm) deep (including connectors)

    Linear Power Supply:
    12" (30.48 cm) x 3.25" (8.26 cm) x 4.25" (10.8 cm)

    Net weight:
    with switching supply: 5.35 lbs (2.5 kg) - amplifier and external power supply)
    with linear supply: 8.94 lbs (4.1 kg) - amplifier and external power supply)

    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.



    Last edited: Jan 21, 2019
  2. jerick70
    Interesting design. Subbed
  3. Tao8
    Something of a hard call this, go MZ3 or MZPre, feeling a bit caught between a rock and a hard place on this one.

    Will have to be making the call shortly and Jack at Audio Beatnik will be reviewing the MZ3 soon so maybe he’ll shed some light on this.
  4. Matthew Willims
    Certainly interested in this review, though may just get the upgraded Linear Power Supply for my MZ2....

    Thinking about fabrication of a new cover using a stainless mesh though as not really a fan of the clear top. I don't need to see the internals and ventilation is always a plus.

    Of course if the reviews say the MZ3 destroys the 2 I'll have no choice but to save for one :wink:
    Tao8 likes this.
  5. jamato8 Contributor
    I should have a MZ3 in a few days and will post more images and initial impressions.
    jerick70 and Tao8 like this.
  6. Matthew Willims
    I'm a bit envious of your acquisition.... Wish you had a MZ2 for a head to head. The MZ3 is a lot nicer looking though I'm particularly interested in the difference in performance.
  7. jamato8 Contributor
    I have the MZ2 with the LPS. It also has a Goldpoint attenuator. Excellent sounding, very 3D and dynamic with wonderful separation and staging. Will compare once the MZ3 is broken in.
    Matthew Willims likes this.
  8. Tao8
    Very much looking forward to your thoughts on the differences with your MZ2... I’m also currently using the MZ2 with a linear supply and still considering the upgrade to the MZ3 or MZpre so any feedback will be a great help.
    Matthew Willims likes this.
  9. bdh
    Wish they had a headphone only version without the input selection, output selection, and speaker output -- overall much simpler wiring -- for ~$700 cheaper. :ksc75smile:
    It would seem like an easy option to build and offer. Just a wish.
  10. jamato8 Contributor
    Parts cost with labor adds little to the cost. I doubt it would be much cheaper without the option but know that the thrust of the MZ3 is as a headphone amp but having heard from a couple of people who have used the MZ2 as a preamp, it is well worth have the option. I have some very nice modified Klipsch speakers but in storage, I would love to see how it sounds at moderate levels.
  11. bdh
    Yeah, I have speakers that this could drive, but can't imagine not using my 45-based amps for that purpose.
  12. jerick70
    I have a set of Zu Omen IIs that paired considerably well with the MZ2. I moved to a Modwright LS 100 pre with a Pass ACA low watt power amp and they do really well with this setup too. If you haven't tried Zu Audio speakers I would recommend an audition.
  13. Matthew Willims
    Did you lose the remote volume control with the Gold point attenuation? It would certainly be better than the ALPS Blue

    Thinking about a Khozmo 64 step motorised attenuator for mine. I don't know of any other decent motorised units available.
    Last edited: Jan 20, 2019
  14. jamato8 Contributor
    No it is the manual attenuator. It is a headphone amp, not far away from me and a motorized attenuator would not be needed in my case.

    The attenuator on the MZ3 is a totally different animal. And the two boards are ceramic, which pretty much gets rid of any capacitance from the board and cleans up the higher frequencies and improves transparency.
  15. jamato8 Contributor
    The MZ3 has the remote that has many functions on it.
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