[yukihasi]

 
There are many considerations we have to take and limitations regarding what we offer, and, regarding the MicroZOTL2, we have had more requests for more features than less. There's also the fact that the success of MicroZOTL2 itself is a funny result of add-ons. Originally it was only going to have speaker outputs, and it sounds incredible with speakers, but you'd really need about three more MicroZOTLs in the case to make it an amp that would satisfactorily power the highest sensitivity speakers (which would price it above our 10 watt amp). And then the headphone output was thrown in, and then the preamp outputs, both of which developed followings that the speaker outputs have not, but as a result it does three things in as simple a way as possible

Makes perfect sense, and not to mention the original microzotl also have all of the three functionalities. 
 
But what I really hope is the next "pre-amp with headphone out" from LTA, which mentioned before in the post, to be a "headphone amp with pre out", or at least we can choose between the two optimized version. 

 

[Jozurr]

Proud new owner here. I already have a Liquid Glass, but curiousity got the best of me and I got the MZ2 with LPS.
 
I have some simple questions:
 
1) I have the version with the LPS. If I decide not to use the LPS, how does the MZ2 power? I only have a small power in port thing, and a cable that goes into the port and into the LPS, and power cord out of LPS to wall
 
2) How big of a difference does rube rolling make in this amp? Do changing the 6SN7 or the 12AT7 make a bigger difference? It seems difficult to tube roll considering you have 14 screws to open and close, unless you decide to keep the top open in which case I risk getting dust in it
 
3) I plugged in the HE-6 in it as well. However, as I go near 3-4 o clock on the volume pot, I heard some distortion coming in. Is this normal? What could be the reason?
 
Also, I really with this had a 4pin XLR out as all my headphones have these cables, and I hate working with adapters. A simple 6.5mm to 4 pin XLR would have been ok, just like the one on the Liquid Glass. There's ample space on the front for it too.

 

[sheldaze]

 
2) How big of a difference does rube rolling make in this amp? Do changing the 6SN7 or the 12AT7 make a bigger difference? It seems difficult to tube roll considering you have 14 screws to open and close, unless you decide to keep the top open in which case I risk getting dust in it

I think there is significant change in sound from both tubes. However I have only changed the 6SN7 once. These tubes can be costly, and I've read they do not make as significant of a change as do the 12AT7. And I am hesitant to pay the $100 per tube to get the Sophia Electric 6SN7 tubes that I'd really love to hear, only to find out they sound similar to my inexpensive eBay set of four tubes, for which I paid $65 total, including shipping cost.
 
The 12AT7 though, I've listened to stock, Telefunken, Mullard, and Gold Lion. I think you might be soon able to purchase Gold Lion from the manufacturer, and that's what I would recommend. When I used the Mullard and the stock 6SN7, I thought it lost something. I am, however, using the Mullard with my eBay tubes and like the pairing. Go figure - I'm a tubes newbie, and I do not understand. I just like what I hear!

 

[willsw]

  Proud new owner here. I already have a Liquid Glass, but curiousity got the best of me and I got the MZ2 with LPS.
 
I have some simple questions:
 
1) I have the version with the LPS. If I decide not to use the LPS, how does the MZ2 power? I only have a small power in port thing, and a cable that goes into the port and into the LPS, and power cord out of LPS to wall
 
2) How big of a difference does rube rolling make in this amp? Do changing the 6SN7 or the 12AT7 make a bigger difference? It seems difficult to tube roll considering you have 14 screws to open and close, unless you decide to keep the top open in which case I risk getting dust in it
 
3) I plugged in the HE-6 in it as well. However, as I go near 3-4 o clock on the volume pot, I heard some distortion coming in. Is this normal? What could be the reason?
 
Also, I really with this had a 4pin XLR out as all my headphones have these cables, and I hate working with adapters. A simple 6.5mm to 4 pin XLR would have been ok, just like the one on the Liquid Glass. There's ample space on the front for it too.

 
Happy to hear your curiosity was so strong.
 
1. MicroZOTL2 is designed with an external power supply–a power supply outside of the case holding the audio components–the LPS is this power supply. It is equivalent (but much higher quality) to the wall-wart on a computer charger. If you don't want to use the LPS, there are many manufacturers who make standalone power supplies with connectors that will fit our unit, or you could even use an adequate battery to power the unit–the original microZOTL actually had battery power as a primary option.
 
2. The MicroZOTL2 (and all amps using the ZOTL circuit) is very sensitive to tube rolling. Generally people find a larger difference in changing the 12AT7. The case was admittedly designed without tube rolling in mind. If you were going to tube roll a lot, you could secure the top with only a few screws, and it would be fine.
 
3. The HE-6 is an extremely low sensitivity headphone: rated at 83.5db/w but that's possibly optimistic. The MicroZOTL2 will not get these very loud before they start to distort, because it simply does not put out enough power to make them louder. Most amps aimed at headphones will not give enough power to the HE-6.
 
We made the decision not to put the 4pin headphone output on the MicroZOTL2 for several reasons. It is possible to modify or have someone modify the headphone jack, and replace the current 1/4" output with a 4pin. The hole in the faceplate should accommodate the other headphone jack. Or you could just leave something like this plugged in: http://www.alliedelec.com/neutrik-na3fp/70088406/

 

[jamato8]

There are a number of 6SN7 types that don't cost 100 dollars each. There is a 6SN7 thread on this forum that will give you many options. For me, I find that both the 6SN7 and the 12AT7 can have significant affects on the sound. Normally the output tube has less but with the mZ2, I don't find this to be true. For me this is a good thing as you can have many options. There are many 12AT7 tube types available and it is always worth it to have a few sets of tubes to roll or for back up. 
 
I have worked with tubes for years and have a few 1000. There is no need though for more than a couple of pairs. On the HE6, as mentioned above, the mZ2 was not designed for this type of phone. I have the HE6 and it requires a lot of power and to have 5 watts minimum is best. For everything else I have the mZ2 does excellent and no amp I have listened to can match it. If people realized how good the mZ2 sounds, and for a price that would normally get you a lesser amp, Linear Tube Audio wouldn't be able to keep them in stock. 
 
I also have a battery from Anker, that output 12 volts and will power the mZ2 for many hours. It is surprisingly small but allows for a transportable use of the mZ. 

 

[sheldaze]

  There are a number of 6SN7 types that don't cost 100 dollars each. There is a 6SN7 thread on this forum that will give you many options...

Long thread, so I'll be back in a few months 

Although post #2 describes what I am using, and the Sophia that I was interested in giving a trial.

 

[Jozurr]

  I think there is significant change in sound from both tubes. However I have only changed the 6SN7 once. These tubes can be costly, and I've read they do not make as significant of a change as do the 12AT7. And I am hesitant to pay the $100 per tube to get the Sophia Electric 6SN7 tubes that I'd really love to hear, only to find out they sound similar to my inexpensive eBay set of four tubes, for which I paid $65 total, including shipping cost.
 
The 12AT7 though, I've listened to stock, Telefunken, Mullard, and Gold Lion. I think you might be soon able to purchase Gold Lion from the manufacturer, and that's what I would recommend. When I used the Mullard and the stock 6SN7, I thought it lost something. I am, however, using the Mullard with my eBay tubes and like the pairing. Go figure - I'm a tubes newbie, and I do not understand. I just like what I hear!

 
Thanks for the recommendations. Although I have a few pairs of 6SN7 tubes since I use them on the Glass, so I can maybe roll them into this. There are some really good tubes available for even USD 50 per pair, which I believe might be better than the standard ones on the MZ2.

   
Happy to hear your curiosity was so strong.
 
1. MicroZOTL2 is designed with an external power supply–a power supply outside of the case holding the audio components–the LPS is this power supply. It is equivalent (but much higher quality) to the wall-wart on a computer charger. If you don't want to use the LPS, there are many manufacturers who make standalone power supplies with connectors that will fit our unit, or you could even use an adequate battery to power the unit–the original microZOTL actually had battery power as a primary option.
 
2. The MicroZOTL2 (and all amps using the ZOTL circuit) is very sensitive to tube rolling. Generally people find a larger difference in changing the 12AT7. The case was admittedly designed without tube rolling in mind. If you were going to tube roll a lot, you could secure the top with only a few screws, and it would be fine.
 
3. The HE-6 is an extremely low sensitivity headphone: rated at 83.5db/w but that's possibly optimistic. The MicroZOTL2 will not get these very loud before they start to distort, because it simply does not put out enough power to make them louder. Most amps aimed at headphones will not give enough power to the HE-6.
 
We made the decision not to put the 4pin headphone output on the MicroZOTL2 for several reasons. It is possible to modify or have someone modify the headphone jack, and replace the current 1/4" output with a 4pin. The hole in the faceplate should accommodate the other headphone jack. Or you could just leave something like this plugged in: http://www.alliedelec.com/neutrik-na3fp/70088406/

 
So had I bought just the MZ2 without the LPS, how would I have powered it out of the box? I have to buy something extra to run the MZ2 without the LPS if I want to compare the differences with and without the LPS?
 
I understand that the HE-6 is difficult to power, and Im currently using a huge power amp with LG as a preamp, and I just tried the MZ2 as a preamp as well. What I was wondering is, why there would be distortion on the HE-6 when I go near the max on the volume pot, since that doesnt happen with most amps. They just give up and not go loud enough after I hit max volume. I just plugged in another Hifiman, and the same issue happens with it too. 
 
Also, from what I understand, if I plug in the headphones, the preamp wouldnt get cut off? So for example, if I leave the 6.5mm to 4pin XLR adapter on and leave the headphones plugged in to it or not, I can still use the MZ2 as preamp too? With the volume knob controlling both the headphone out and the preamp at the same time? I dont want to try it since the power amp will blow up my HE-6 if it doesn't work as intended. So currently, I plug out everything from the headphone out, if I have to use the MZ2 as preamp, and plug the headphones back in to use MZ2 as a headphone amp.

  There are a number of 6SN7 types that don't cost 100 dollars each. There is a 6SN7 thread on this forum that will give you many options. For me, I find that both the 6SN7 and the 12AT7 can have significant affects on the sound. Normally the output tube has less but with the mZ2, I don't find this to be true. For me this is a good thing as you can have many options. There are many 12AT7 tube types available and it is always worth it to have a few sets of tubes to roll or for back up. 
 
I have worked with tubes for years and have a few 1000. There is no need though for more than a couple of pairs. On the HE6, as mentioned above, the mZ2 was not designed for this type of phone. I have the HE6 and it requires a lot of power and to have 5 watts minimum is best. For everything else I have the mZ2 does excellent and no amp I have listened to can match it. If people realized how good the mZ2 sounds, and for a price that would normally get you a lesser amp, Linear Tube Audio wouldn't be able to keep them in stock. 
 
I also have a battery from Anker, that output 12 volts and will power the mZ2 for many hours. It is surprisingly small but allows for a transportable use of the mZ. 

 
I'm part of the 6SN7 thread and have some pairs that Ill be trying. Which ones are you using on your MZ2?
 
I have no experience is with the 12AT7 tubes. Which ones do you consider the best 12AT7? What would be your recommendations? Just one liners describing the changes with the tube names would be cool
 
Thanks!

 

[jamato8]

  I'm part of the 6SN7 thread and have some pairs that Ill be trying. Which ones are you using on your MZ2?
 
I have no experience is with the 12AT7 tubes. Which ones do you consider the best 12AT7? What would be your recommendations? Just one liners describing the changes with the tube names would be cool
 
Thanks!

I like the Sylvania 6SN7W black base short tube (over the Sylvania 6SN7GT bad boy) and the Amperex (most all were made by them) 7052 for the 12AT7. 

 

[Maxx134]

The mods I got from Mojo Audio were: 
* A 24-step Goldpoint attenuator.

This in my opinion is the biggest upgrade.

In my experience at the last NY headfi meet,
this amp was only bettered by one TOTL system and and electrostatic setups.

I was rather shocked at the strength and clarity.

So I am wondering are the tubes biased normally?

What about the heater current?
How high can it go for tube rolling?
I asume this unit using external PSU, so heater current can be increased if needed.....
It would open the unit to more tube rolling choices. ..

For example, although a tube can be optimally biased for maximum linearity,
I still find the 6sn7 family superior to any 12at7 type.

I have been using 6sn7 as driver tube on another amp project, and would be curious to try same on this amp.

Edit :
Regardless, the output design is genius.

 

[willsw]

This in my opinion is the biggest upgrade.

In my experience at the last NY headfi meet,
this amp was only bettered by one TOTL system and and electrostatic setups.

I was rather shocked at the strength and clarity.

So I am wondering are the tubes biased normally?

What about the heater current?
How high can it go for tube rolling?
I asume this unit using external PSU, so heater current can be increased if needed.....
It would open the unit to more tube rolling choices. ..

For example, although a tube can be optimally biased for maximum linearity,
I still find the 6sn7 family superior to any 12at7 type.

 
The circuit is auto biasing, and the tubes are run at low current which results in a very long life. The times I've seen users increase heater current, it has been with a separate power supply only for the heaters. 

 

[Jozurr]

Still hearing distortion if I go past 3 o clock on the volume knob. Same input and everything else similar is crystal clear into the LC and LG. Anyone knows what could be wrong?

 

[Jozurr]

So had I bought just the MZ2 without the LPS, how would I have powered it out of the box? I have to buy something extra to run the MZ2 without the LPS if I want to compare the differences with and without the LPS?

I understand that the HE-6 is difficult to power, and Im currently using a huge power amp with LG as a preamp, and I just tried the MZ2 as a preamp as well. What I was wondering is, why there would be distortion on the HE-6 when I go near the max on the volume pot, since that doesnt happen with most amps. They just give up and not go loud enough after I hit max volume. I just plugged in another Hifiman, and the same issue happens with it too. 

Also, from what I understand, if I plug in the headphones, the preamp wouldnt get cut off? So for example, if I leave the 6.5mm to 4pin XLR adapter on and leave the headphones plugged in to it or not, I can still use the MZ2 as preamp too? With the volume knob controlling both the headphone out and the preamp at the same time? I dont want to try it since the power amp will blow up my HE-6 if it doesn't work as intended. So currently, I plug out everything from the headphone out, if I have to use MZ2 as headphone amp.

Still looking for answers for these too. Any help will be appreciated.

 

[crazychile]

So had I bought just the MZ2 without the LPS, how would I have powered it out of the box? I have to buy something extra to run the MZ2 without the LPS if I want to compare the differences with and without the LPS?

I understand that the HE-6 is difficult to power, and Im currently using a huge power amp with LG as a preamp, and I just tried the MZ2 as a preamp as well. What I was wondering is, why there would be distortion on the HE-6 when I go near the max on the volume pot, since that doesnt happen with most amps. They just give up and not go loud enough after I hit max volume. I just plugged in another Hifiman, and the same issue happens with it too. 

Also, from what I understand, if I plug in the headphones, the preamp wouldnt get cut off? So for example, if I leave the 6.5mm to 4pin XLR adapter on and leave the headphones plugged in to it or not, I can still use the MZ2 as preamp too? With the volume knob controlling both the headphone out and the preamp at the same time? I dont want to try it since the power amp will blow up my HE-6 if it doesn't work as intended. So currently, I plug out everything from the headphone out, if I have to use MZ2 as headphone amp.

Still looking for answers for these too. Any help will be appreciated.

@willsw already answered your distortion question

 

[zachawry]

  Proud new owner here. I already have a Liquid Glass, but curiousity got the best of me and I got the MZ2 with LPS.

 
I was all set to get the Glass, but decided I didn't want to wait more than 6 months, so I got the MZ2. I am very happy with the MZ2, but I'd still be curious to hear your comparison with the Glass. 
 
Re: Power supplies: I originally got mine with the very basic SMPS power supply. I think they might not even provide these any more. Then I upgraded to the LPS, and the difference was amazing. That got me on the power supply bandwagon, and now I have an even better power supply (Joule 5 from Mojo Audio). Each upgrade has been a large jump in terms of background blackness, speed, and clarity. 
 
Funny, I didn't even realize background blackness was a thing until I got the LPS, when I immediately saw that the background had been just darkish grey before.
The LPS *seemed* pitch black, but with the J5 I see that it was only, errr....very dark grey.

 

 

[Jozurr]

@willsw already answered your distortion question

I thought that he only meant that for the HE6. I plugged in my LFF Code X (HE5) as well. They are lets say equivalent to HE500 power requirements wise and get too loud on the LC even under half way on the volume knob and the MZ2 cant even power these without getting distorted? Then I plugged in my Omnis and same results. Why do I keep reading these have enough power for most headphones and what not?

I read enough comparisons between the LC and MZ2 mentioning how MZ2 trumps the LC in all possible ways, without anyone mentioning that these just dont have the power for many headphones, and I assumed specs dont say everything about amps. I might be missing something completely or these are maybe just made for very easy to drive headphones only.