Linear Tube Audio - Micro ZOTL - version -3 Update on upgrades

Thanks for the feedback @smatsui . Seems like both you and audioman58 think it is a worthwhile upgrade. Just curious if you think it also sounded better with the XA25 or only the F7. Looking forward to any additional feedback from cbrez and thriftyaudio, Happy listening.

Got my Level 3 upgrade back last week. It did need a bit of break in within my system. 
First off - the immediacy. The Level 2 might have been a little bit laid back, but the Level 3 takes care of that. It is fast and very dynamic. This is the really stands out. Instruments just pop in a way that did not happen before. The word that really did come to my mind is immediacy - fast, dynamic, and wonderful.

There is a bit greater extension or perhaps clarity that stands out on both the high and low end. Cymbals shimmer a bit more than ever and the notes of a standing bass are more taut. The midrange is still outstanding. The LTA is not an old school tube preamp,with the lush, dense midrange of old CJ sonics, but is also not like a lean SS preamp either. The Level 3 upgrade maintains for me the clean, present midrange quality that was there before. Perhaps a bit “cleaner” than before, which makes sense given the apparent attention to lowering the noise floor in this redesign. 
The Level 3 may be a tad bit more forward sounding than the Level 2. I want to give it a little more time here though. Also not a bad thing, but just a slight difference I am hearing so far.

I am very pleased I had the upgrade done. LTA was very good at communicating status, not surprising given my past interactions with them. The Level 3 is still a great companion to my Pass XA25 and I am very happy overall with LTA and this upgrade.

Are you people that did the upgrade comparing level 3 to level 2 using the same tubes? 

I can dramatically improve the sound of my level 2 by tube swapping. 

My Level 3 upgrade arrived Friday and I have spent a large part of the weekend listening to music. The total turn around time was eighteen days including shipping from the West Coast to Maryland and back again. Fortunately I was traveling during much of that time.

I let the system play for twelve hours before I started any critical listening. It is very difficult to compare the Level 2 versus the Level 3 results without having them side by side. This is the same issue I have had comparing power amps, speakers, preamps, and DACs. I expect I will have the same difficulty as I upgrade my streamer.

Fortunately, I anticipated the issue and had notes regarding particular songs  and source material. Across the board I found the instrument and performer separation was improved. Frequently the singer, or featured instrument was brought forward slightly. Stage presence height improved with Level 3. Level 2, plus all my other preamps over the years had exaggerated placement relative to what they should be. Level 3 is the first preamp that I have owned to nail the height issue. Things that are suppose to be overhead (think Pink Floyd, soundtracks with singers on different floors, and helicopters) are where they should be. The soundstage placement is consistent a joy to listen to.

Regarding background blackness: I am not certain I can tell if there is an improvement, or even a change. There might be, but I am unable to identify it. 

Some instruments seem to have a more natural extension. The Level 2 improved this area versus the Benchmark LA4. The Level 3 is better than the 2 with this as well.

Bass is more accurate in the extreme (under 30 Hz). The extreme bass in Imagine Dragons' "Radioactive" is actually tamed a bit. I didn't have to rush to turn it down because the house was shaking. The house still shakes with the cannon from The 1812 Overture as it should. Bass placement is a bit more detailed and tight.

I am very glad I decided to the get the Level 3 upgrade. It compares favorably to the Backert Labs Rhumba Extreme 1.4 (have not heard the Rhythm 1.4).

Regarding tube rolling: I have the original NOS tubes shipped with the unit plus the Ray Reserve and Gold Lion tubes LTA offers. The upgraded tubes still sound much better than the standard tubes. I am not inclined to try many different tube pairings. I will leave that with the pros, in this case LTA. I did enquire regarding the Ray Select tubes LTA is now offering in place of the NOS Gold Lion. The replied that there would be a slight difference, but not much and that is could be perceived as an improvement or a downgrade depending on my perception. I may buy a pair down the road, but not the immediate future. There may be better tubes out there, but that is not path that I will be exploring for now.

@sls883, same tubes in my level 3 that I had in my level 2.  I have about 200 hours on my level 3 in addition to the 1 week of burn-in at LTA.  I think it’s improved from the time I first received it.  I have not tried it with my XA-25 yet.  I’m using Sylvania 6SN7 from the late 50’s/early 60’s and Mullard 4024 (12AT7).  I like those tubes better than the stock tubes.  I also purchased the Ray Reserve 6SN7 but I haven’t tried them yet.