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LTA MicroZOTL tube upgrade

Hi everyone,


I’m thinking about changing the default tubes in my gear and was wondering if anyone has experience with replacing the stock 12AT7s with Ray Select 12AT7 or any other tubes that add some warmth and density to the sound.

gabriel123
tyray
1,040 posts
 

@gabriel123,

I bought a slightly used LTA Microzotl MZ3 from LTA and my final upgrade was to the matched NOS 1940’s (1) Sylvania 6SN7W metal base and (1) Sylvania 6SN7GT metal base, which have different nomenclatures but are the exact same tube and (2) matched NOS Telefunken ECC801S’s. 

And this is after an upgrade from the stock tubes to (2) matched NOS Telefunken ECC801S’s and (2) Matched NOS Sylvania 6SN7GT 1952 ’Bad Boys’ which are also excellent tubes but the the matched NOS 1940’s (1) Sylvania 6SN7W metal base and (1) Sylvania 6SN7GT metal base just brought it to an even higher level of performance.

I also upgraded to the 聖HIJIRI HCI R10 RCA interconnects and the 聖HIJIRI Nagomi Power Cord and at each upgrade the LTA Microzotl MZ3 responded with very positive results each time. And that’s one of the many things I like about this gear is it does respond to changes good and/or bad. 

The only thing I haven’t upgraded is the umbilical power cord as of right now I don’t have the available funds to do so. For the money and what it does, this is the best preamp I’ve ever owned. 

gabriel123 OP
91 posts
 

Thank you all for you feedback!

@chickenoregg Any idea what's the difference between Brimar Triple-Mica Black Plate CV4024 and  Brimar Yellow T 6060? What's so special about Marconi B309 and GEC A2900? GEC is above my budget but I found a pair of " B309 12AT7 ECC81 Black Plate Ring getter NOS Marconi UK Valve Tubes" in good price.

 

 

chickenoregg
39 posts
 
@sls883 @larsman @itball 
 
For the 12SN7 there are two tubes that should be on your radar if they aren’t already. The first is the Tung Sol Black Glass Round Plate 12SN7GT. This is on the list of best 6/12SN7 ever produced. I have put this tube into LTA gear for clients more than any other tube. The tube that I think is even better (no one that has bought one from me has disagreed) is the GEC B36 which is a 12SN7 and the 12.6v brother to the 6.3v GEC B65. Notably, metal based pairs of the B65 are listing and selling for $4,000+ per pair on eBay currently. I have both B65 and B36 and have one extensive back to back listening session and if there is a difference I’m not hearing it and I listen to tubes critically 12+ hours everyday because that’s what I do. For reference you can pick up a GEC B36 pair of tubes for about 20% of the cost of those B65’s. Quite possibly one of the best if not thee best value in tubes out there. Which is true for many high end 12SN7. 
 
 
Be careful with listing titles. 
 
Sellers stuff every possible "equivalent" they can into headlines to get more search results. For instance a regular old RCA Black Plate 12AT7 will have a title like RCA 12AT7 B309 A2900 ECC801S CV455 6060 E81CC ECC81 CV4024 M8162.  
 
Equivalent is also a suspect term because they are not necessarily true equivalents in construction, electrical parameters/ratings, or sound quality. Being able to substitute or use doesn’t mean it’s an equivalent. This is important because many "equivalents" may draw 2x the heater current from your piece of kit and while it works over time will damage or kill your transformer or other parts in your power supply. I’m not a preachy "just do whatever the manufacturer says" kind of guy, but you should make an informed decision about what level of risk you are willing to trade off for an improvement in sound quality.  
 
Some sellers know these tubes are different and approach it with a caveat emptor attitude — that it’s your responsibility to know that. Other sellers do not have the first clue and actually think these tubes are identical which is equally dangerous.
 
 
You’re doing it right. Try some GEC a2900s instead of those ECC801s. I think you’ll be happy you did.
larsman's avatar
larsman
3,154 posts
 

@chickenoregg - thanks for all that good info and suggestions, and I've made note of them for future reference. I like the LTA right now, so I just want to turn it on and listen to music. I don't think I'm that heavy of a tube roller - Happy New Year!  

chickenoregg
39 posts
 

@larsman 

We chase sound quality, but contentment is a higher mountain to have climbed. I am considering an LTA Preamp and LTA DAC to pair with my VAC 200IQ. Perhaps I will meet you on the summit soon.

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