MicroZOTL 2

Endless tube life. :-D Well, despite the statements of performance capabilities that transcend space and time, I do think the Zotl has a place and is worthy of consideration especially if it is truly capable of driving planars with power to spare. By the rational accounts I have gathered from folks whose ears I know in order to try to piece together a complete picture, it's a modern neutral tube sound rather than an overly warm vintage sound, with the holographic 3D soundstage and respectable resolving ability. I would expect some grain, but I can't quite get a read on that yet. Everyone calls it smooth. Do they mean in the absolute sense, or smooth for an OTL amp? Apparently it's dead silent and you can't tell it's on with the volume all the way up. Pretty impressive, that. And apparently Linear has a 15 day money back trial period, so once I get my ducks in a row I think it can't hurt to give it a shot and see for myself.

Happy New Year!

 

Just took delivery. The Microzotl2 takes it's place next to big brother in the background as listening evals begin!!

Early impression: This is a peppy tube amp. And there's plenty of power on tap: my ETHER-C 'phones are a tad too loud at about 10:00 on the volume dial.

 

Early thoughts on the microZOTL2 follow.

My eval setup is simple:
Mac Pro running Amarra for Tidal FLAC --> Mojo Audio Mystique V2 DAC --> microZOTL2 --> ETHER-C cans (still using 1.0 tuning)

1. This is a very energetic tube amp. Particularly in the treble region. Blindfold your friend, and he'll first wonder if he's listening to a solid state amp....

2. The soundstage is nice, as expected. The blindfolded friend will start to wonder which solid state amp can throw this kind of staging. I would guess that with choice tube rolling, imaging can become more precise too.

3. At its price point, it just does a whole lot very well. It's clean, crisp, relatively uncolored, and super detailed (more on that below, though). Comparing this to my recollection of amps such as the Cavalli LC, the AGD NFB-1, sub-$1k Schitt gear... it's a no brainer for me. The microZOTL is the bees knees among them. While the Mjol was probably a bit more tame in the treble, my recollection is that its soundstage wasn't as expansive.


Nitpicks:

1. I'd look to tame the energetic mid and upper-mid ranges. I'd characterize it as having a bit of glare in this region, which is common with stock Russian tubes anyhow. Not unexpected. And I wouldn't call it overly harsh either, just that I think it can be improved.

2. The hyper detailed forward sound is what I'd consider "clinical". For example, if I were a headphone or DAC manufacturer, I might consider this a great R&D device because everything is right up front and easy to evaluate. But the downside is this becomes less euphonious, and this is my biggest nitpick. I feel, particularly in live recordings that I'm intimately familiar with, details and micro details aren't as layered and nuanced as they should be. Instead of a presentation with depth, this amp takes a more brute force approach of putting all the details right in front of you.

3. It's a tad thin. Not terribly so. But the somewhat thin lower-mid to upper-bass region is also contributing to the hyper detailed presentation.

I do want to try Mullard and Telefunken 12AT7 pairs. The former is going to impart some warmth, possibly expand the soundstage, and maintain the airy high end. The latter was my favorite tube in the 12AX7 variant for a homemade headphone amp long gone now... about 15 years ago. Man, I'm getting old. But 12**7 Teles are just super transparent without the slightest hint of glare in my previous experience, and I've always known I'd come back to them.



Lastly... I'm quite curious to hear what a good LPS does.

 

thanks very much for this clear first impression... very interesting

 

I've got a few select NOS tubes arriving. I found a true NOS pair of Telefunken diamond bottom 12AT7s in sealed boxes. (The cellophane itself looks old, so it appears to be the real deal). I also picked a pair of Mullard 12AT7s to warm it up a bit. Lastly a set of Raytheon 6SN7s... Said to be very similar to the fan-favorite (and 2x priced) old stock Tung Sol round plates.

So, more details to come. But I think I'm going to like this amp even more with a few tube tweaks.

 

Alright, well, after having spent some extended time with the microZOTL now, I thought I'd go ahead and update the thread here.

The treble I first reported as not necessarily "harsh" did get the best of me. Shortly it became clear that in its stock configuration, I was not going to enjoy extended listening sessions. I think the best adjective to describe the general sound signature might be "glassy". But my tube rolling experiments have paid off. Still using the stock switch mode power supply, I have found the combination of Raytheon 6SN7s and Mullard 12AT7 do enough to take the edge off. Neither one nor the other on their own suffice, but together the combination is a big step forward. The glare has given way to a slight warmth. The forward hyper-detailed presentation has mellowed out, but micro details are still resolved. And even soundstage seems to have expanded for a more "out of head" sound. With this combo, listening to an album such as Sara Barelleis' Brave Enough Live from start to finish is not only possible, but enjoyable. The sound is simply more engaging, non-fatiguing, warmer and fuller, and now has me bouncing around in my music library eager to hear how my favorite tracks sound through the system.

By the way, an interesting tube I acquired on the cheap, which I think some have taken a liking to in the Torp3, is the Amperex 7062. This seems to be a very transparent tube with an even more expansive soundstage than I'm currently experiencing with my Raytheon/Mullard tube combo in the microZOTL. However its transparency did allow the glassy signature - particularly in female vocals - to emerge once again, so I felt the need to revert back to the Mullard 12AT7s. And that's interesting because it seems the stock Tung Sols are not the source, but rather the amp (and/or PSU) design itself. Nevertheless, once my linear power supply is put together, I fully intend to come back to the 7062s in anticipation of a different sound altogether. Oh and speaking of stuff yet to come, I also decided to experiment with round plate VT-99s - in this case National Union - so a pair of socket adapters are also on the way. I suspect the main "advantage" of the VT-99s is going to be gaining access to round plate tubes, such as the Tung Sols, at a lower price than the 6SN7 versions. Other folks do seem to claim further sonic differences as well, though. So we will see.

Fun stuff!

 

Where are you putting together your PSU?? 12V and 3.4 A ?

 

Good question. But I'm not sure where you get 3.4A? The stock switch mode PSU is rated at 2.5A, and I don't think the continuous current demand is 2.5A.

Anyhow, I'm going to try the s11 PSU with larger heat sinks and enclosure vent holes.

 

By the way, it looks like they just released the Linear Tube Audio LPS. It'll be $395 for those who already own the microZOTL, $595 for new customers.

After many requests, careful design and testing, Linear Tube Audio now offers its own linear power supply for the MicroZOTL2. Designed specifically for the MicroZOTL2, the power supply is low heat (just like the amp itself) with the amp at continuous, full output. We use organic-polymer caps for super low ESR and a medical-grade EMI filter. The power supply, with its low noise toroidal transformer, gives extremely clean and quiet power.

 

What's a non-rando? Whatever it is, I suppose the question implies that my impressions are invalid. But the concern over what folks do with their money should be well mitigated in this case by the fact that there is two week money-back audition period. Also note that I haven't drawn any direct comparisons of the microZOTL to my ZDS (#92) because it's not a fair comparison. The Torp3, on the other hand, I would be very interested in comparing but haven't happened upon one.

BTW, isn't there a Bay Area meet coming up the weekend after CanJam? I'd be glad to bring the microZOTL there if I can make it ... unless randos are forbidden.

 

on mine, just below the power input you can find 3.7 A (not 3.4 as mentionned before.............)...................... special EU version??

 

No, I don't think the microZOTL + LPS will supplant the ZDS for me. They're different, though, and for me, the ZDS is just everything I want in euphonic detail.

I don't know if you're Bay Area or not, but if so, I will try to make it with the MZ. Will there be any Torp3's? I'm going to leave the ZDS at home, though.

Edit: I've never seen a used ZDS for $1300 - $1500. That's deal and a half, IMO.

 

Done and done.