FREQUENTLY ASKED QUESTIONS
Please explain the relationship between the "MicroZOTL2.0", "MZ2", and "MZ2-S"
Our first product was a re-introduction of David Berning's MicroZOTL; our MicroZOTL2.0. Since then we've made many small and several larger changes to the case and components we use, but we have always used and continue to use Berning's original circuit. When we added an improved power supply, that product eventually took on the name "MicroZOTL2.0 Deluxe". When we decided to use NOS 12SN7 tubes and manually alter the circuit to allow this, we created the "MZ2-S" around this, with a further upgraded power supply and some other improvements. Eventually we replaced the manually altered circuit boards with jumpered boards, which negated the need for completely separate products and we decided to discontinue certain aspects of the MicroZOTL2.0, like the locking headphone jack and the color scheme, while making other features that the MZ2-S had introduced available as options for any order. The "S" went from denoting these upgrades to essentially meaning the same thing that "Deluxe" had before it; an amp with an upgraded power supply. The "MZ2" therefore took the place of the "MicroZOTL2.0", as our amps were now markedly changed from what the MicroZOTL2.0 had until then been. To make all of this more confusing, most people still refer to any model as a MicroZOTL. The most important thing is that we'll make sure you get the features you want regardless of what it's called in the process.
Will the MicroZOTL2 work with my low-impedance headphones? (Grados, Fostex TH-X00s, IEMs etc.)
Yes, the output impedance of the MicroZOTL2 (and all of our ZOTL amplifiers) is 2 ohms, which means that it should generally work well with any headphone or IEM above 16 ohms impedance, which is the majority of them. It will also work silently, with no hum, with these headphones. With especially sensitive IEMs, a slight hiss is apparent with no source input and the volume turned up, though if music were playing at that volume the drivers would probably be damaged and your ears definitely would.
Regarding ZOTL10/ZOTL40 speaker compatibility
Though technically an OTL amp, the output impedance of the ZOTL amplifiers are very low: under 2 ohms. This means that, in terms of impedance, a ZOTL amplifier is just as happy powering an 8 ohm or 4 ohm (or 2 ohm or 16 ohm) speaker. The ZOTL circuit doesn't match with every speaker, of course, and efficiency plays a large role there; speakers truly requiring a great deal of power will not sound ideal with a 40 watt ZOTL amp. Some of the wide variety of speakers that have been heard to work well with ZOTL amplification: Quad 57s, Maggie Minis, Tekton Design, Fern & Roby, Voxativ, Evoke Eddie, Janszen, Decware, Klipsch, Silverline, Spatial, DeVore, Zu.
Will the MicroZOTL2 work with my "hard-to-drive"/"hard-to-pair" headphones? (Sennheiser HD650, HiFiMAN HE1000, HE-6, HD800)
In some cases, such as the HiFiMAN HE-6, which has notably low sensitivity and thus requires several watts to power adequately, the MicroZOTL2 is probably not going to give you a satisfyingly loud and full listening experience. Since the unique circuit of the MicroZOTL2 reacts very little to different impedances, it is mostly a matter of sensitivity when it comes to which headphones the MicroZOTL2 does well with. Whether it can "drive my headphones" often just means "will I prefer how my headphones sound with this amp." We've read many accounts of people thinking their HE1000 or HD650 has never sounded better than on a MicroZOTL2; I've also read one or two accounts of people saying the opposite. We don't know what you like, but we do know that we've read far more mentions of the MicroZOTL2 sounding good with all kinds of headphones than not.
What difference does the linear power supply (LTA LPS) make over the stock supply?
Regardless of the power supply, the MicroZOTL2 will have a black background with no hum. The switching supply does introduce some distortion and noise at inaudible levels, which is eliminated by the regulated linear power supply. There are several other advantages over the stock supply technically, but it is suffice to say here that performance is notably improved in the treble and bass, clarity increases, and the overall sound quality of the amplifier is bettered.
Can I mono-block the _____?
All LTA ZOTL amps can have their outputs bridged and function as mono-block amplifiers. The ZOTL40 Mk. II has a switch that provides protection to certain equipment that does not like bridged outputs, but in most cases simply connecting the two positive and two negative outputs with an adapter, a shorting rod/shorting cable, or a piece of copper wire will accomplish the task without problem. In addition to achieving approximately 1.7x the wattage of a single, stereo amplifier, mono-blocking gives less distortion, increases dynamics, and provides a larger soundstage.
Can you send me a loaner to try?
After purchasing an amplifier, you have 14 days after you've received it to return an amp for any reason and receive a full refund for the purchase price, assuming the unit is returned in the same condition we sent it. We do not have a loaner to send you.
Will the MicroZOTL2 power my speakers?
If you are sitting at a desk with your speakers about a meter away from you and they are 90+db, you'll probably be happy casually listening to music through the MicroZOTL2. If you're in a small room with speakers 95+db, you'll probably be happy casually listening to music through the MicroZOTL2. If you are wanting to critically listen to music, you'll likely be looking for a speaker with 100+db, though sensitivity is not the only determiner of what a speaker can do with 1 watt.
Are these the new Berning amps?
David Berning Co. is a separate company from Linear Tube Audio, and Linear Tube Audio’s amplifiers are not “David Berning Amps” in the sense that they are produced under his company’s umbrella. LTA licenses the right to use David Berning’s name and his past design for the MicroZOTL2.0 and the amps that he designs for us.
In fewer words: David Berning designs the audio circuitry in Linear Tube Audio’s amplifiers to our specifications; they are LTA amplifiers, not David Berning amplifiers. A primary reason for the formation of LTA was to make Berning's designs available to a wider audience, though we also have plans to make non-Berning products.
Do your amps have subwoofer outputs?
If you are using a ZOTL10 or ZOTL40, you can use the "with volume control" input and the "without volume control" input becomes an output that can be used for subs. With the MicroZOTL2 the preamp outputs can work as subwoofer outputs if you have speakers hooked up.
If I plug my headphones in to the MicroZOTL2, will the speaker and preamp outputs still be active?
With the locking jack*, yes. The outputs are bridged, and all are on at the same time. With the closed-circuit jack, inserting a headphone plug disconnects the speaker and preamp outputs. The speaker and preamp outputs will always be active at the same time.
*We no longer offer the locking jack
Can I use the MicroZOTL2 as a preamp for my DC-coupled solid-state amp?
The MicroZOTL2's preamp outputs were added by LTA (similar to how the headphone jack was added as an afterthought by Berning) just to see if this remarkable little amp could also make it as a preamp. To our surprise, though not surprisingly, it has emerged as an incredible preamp. Due to its genesis, however, it does not have all of the features of a typical preamp: most significantly, it does not have protection for the turn-on/turn-off thumps, which means that a DC-coupled amp could amplify these and damage the speakers. To avoid this, you must turn on the MicroZOTL2 before you turn on your power amp, and turn your power amp off before you turn off the MicroZOTL2. The MicroZOTL2 should therefore be the first thing on and the last thing off. Due to it being designed first as a stereo amplifier, the gain of the MicroZOTL2 is also higher than a typical preamp, so depending on your power amp/speaker combination, you may have less room on the volume knob to adjust. The volume on the MicroZOTL2 is quite sensitive, though, so this shouldn't be inconvenient.