[Birdbrain]

I imagine the M3s sound fantastic being driven by a pair of ZOTL 40s, but can a single ZOTL 10 MkII do them justice?

Also, does anyone have experience using the MZ2 preamp with powerful class D amps, the direction I''m leaning.

The ZOTL 10 MkII is quite a bit more than I was planning to spend, especially if it doesn't have the grunt to drive M3s. No way I can swing the ZOTL 40s. 

[Rusty Jefferson]

You must use caution using the MZ as a preamp with high power and or direct coupled amplifiers.  There is no protection circuit in the MZ to prevent DC from passing to your speakers, say in a power failure or you accidentally turn off the MZ before the amplifier.  The "new" LTA MZ preamp has the protection.

I didn't know the ZOTL 40 could be wired as a bridged mono.(?) I don't know why you'd need more than 1 ZOTL 40 if the speakers are over 90db efficient.

[Birdbrain]

Now that you mention it, I don't think they are. I seem to remember a picture of a Spatial/LTA room at an audio show with a pair of amps being used. I might be mis-remembering. I am old. 

[Rusty Jefferson]

They could be, but I don't know. They may have just used 2 because they wanted monos. Unlike transformer coupled tube amps, Berning's amps don't need a load on them. You could just run 1 channel from each.

40 watts per should be plenty for those speakers,  no?  I wouldn't mate the MZ with a 1200 watt amplifier.  Trade it in on the new preamp with protection circuitry.

[Birdbrain]

I agree 40 watts should be plenty, more concerned on if the 10 watt EL84 amp would be enough.
And, to be clear, would mating the MZ2 as a preamp with a PS Audio Stellar S300 power amp be a danger?

[glynnw]

Just to stir the stew. My 2A3 amp drives my M3TMs quite well. And I have a pair of 45 tube amps commissioned.  But currently my favorite is the new Mivera sold here thru the Circle forums initially. It has 1200 watts into 4 ohms, so I am guessing 300 into 16.  So go with the amp you like - you should be OK.

[Rusty Jefferson]

I agree 40 watts should be plenty, more concerned on if the 10 watt EL84 amp would be enough......

I don't have personal experience with the speaker, but at 94db efficiency it would probably play to moderate levels nicely.

.....And, to be clear, would mating the MZ2 as a preamp with a PS Audio Stellar S300 power amp be a danger?

Potentially yes. Me personally, I wouldn't do that.  You may want to call LTA and discuss it.

[Rusty Jefferson]

The following is from the LTA website.   

"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......"

Which is all well and good, however,  if your power should go out (and back on, as happened to me) it can be unsettling or potentially dangerous to your speakers.  It's not like the little thump one experiences when turning on some equipment. I'm saving up for the dedicated MZ preamp. 

[mav52]

The new  full-featured MicroZOTL Preamplifier does not have the problem noted. Per Mark at LTA, "The new preamp has protection to suppress startup and turnoff thump and does not have the same issue."

[Rusty Jefferson]

As mentioned earlier in this thread.

[Plink]

You could try the LTA amp for up to 15 days and return it, if not a good match to your speakers...or give them a call...they might know.

[OzarkTom]

The Audio Beatnik sure loved David Berning amps at Axpona 2018.

Best Real-World Priced Debut: The LTA ZOTL Ultralinear Amplifier

Linear Tube Audio’s ZOTL Ultralinear Amplifier is the latest design by David Berning utilizing his Zero-hysteresis, output transformer less amp design and custom power supply. It’s built by LTA, has a power output of about 18 watts per channel, and uses 17JN6 tubes. They are built to order in the company’s Tacoma Park, MD shop and have a retail price of $6,800.

This amp was in several systems at the show, and every system it was in sounded great. The most expensive speakers I heard it with were the Daedalus Audio Apollo 11 at $22,800, but it also sounded great with the Spatial and Fern and Robby speakers that are closer to $10,000 per pair. This is a very special amp.

https://theaudiobeatnik.com/axpona-2018-the-beatnik-bongo-awards-part-2/

I had the M3's and the 10 is all I would need.

[Birdbrain]

From Linear Tube Audio's FAQ page:
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.