[willsw]

  Common OTL amps generally work best with high impedance transducers and not so good with low impedance. Since the MZOTL2 design departs from standard OTLs in some ways, does this do anything to overcome the issues with low impedance headphones? Specifically, I'm interested in the MZOTL2 with something like Fostex TH-X00, or TH-900s. but also if I bought this amp, it would be used with all my non-electrostatic headphones. Many of which are in the 25-65 ohm range.
 
Thanks.

 
The MicroZOTL2's output impedance is 2 ohms and general advice is that the minimum impedance you want when matching a headphone to an amp is the amp's impedance multiplied by 8. So, non-scientifically but generally, the MicroZOTL2 should match well with anything 16 ohms or above. Non-theoretically but in practice so far, this is absolutely true. 

 

[jamato8]

  Common OTL amps generally work best with high impedance transducers and not so good with low impedance. Since the MZOTL2 design departs from standard OTLs in some ways, does this do anything to overcome the issues with low impedance headphones? Specifically, I'm interested in the MZOTL2 with something like Fostex TH-X00, or TH-900s. but also if I bought this amp, it would be used with all my non-electrostatic headphones. Many of which are in the 25-65 ohm range.
 
Thanks.

The MZ2 is not a traditional OTL. As noted above the output impedance is in a decent range and much lower than a normal OTL. I find it does great with my TH900 with zero problems driving them. Excellent bass and very open sounding. 

 

[defbear]

I have th900's and ether-C's. I wanted a TOTL SE amp for the th900's. I'm not dissapointed. The real surprise are the ether-c's with the microZOTL. Detailed, open and euphonic at the same time. Glorious.

 

[drbluenewmexico]

UPGRADING THE microZOTL2:   a collaborative project with Ben Z from Mojo Audio, Part One
 
Yesterday i began a series of listening tests with a modified microZOTL2 that Ben Zwikel , he'd of Mojo-Audio
brought over. this is the first of a series of upgrade listening experiments to see what different mods help the
ZOTL2 bring maximum performance to headphone listening.
 
I introduced Ben to the ZOTL2 when i was rereleased, having had the original one for years. Ben fell in love with sound and used it
to design and test his TOTL DACs and power supplies he designs as Mojo Audio. This newly modified ZOTL2 was
a stripped down version, with NO NEW PARTS added, no new wiring, following Ben's philosophy of "less is more" it is the orginal
identical to my ZOTL2 prototype but with:
power knob and circuit removed (powers on directly from Joule V power supply)
power amp output and speaker outputs completely removed.
shared circuit paths decoupled and re routed (but with same wires) to separate signal from source)
no unused circuits remain.  
 
Testing included two headphones, the X00 Massdrop Mahogany phones and HiFiMan400i with upgraded speaker wires
Signal path included my usual macbook air running Media Center 21, and Tidal, fed to a usb VLink with optical output
to Mojo-Audo Mystique V1 DAC, with Mojo Audio interconnects into the ZOTL2.
 
Test tracks included Joe Bonamassa and Randall Bramblett, excellent blues recordings....
 
Results:   My untouched Prototype ZOTL2 was all heated up and ready when Ben arrived and we listened to a number of cuts of the blues
before switching it out for Ben's stripped down "hot rod" MicroZOTL2, which described as "like going from a good sedan to a hot rod stock car"
There were no new parts or tubes in the new version, only less.  the new case had holes in it where the power knob and extra outputs had been.
the top was off, otherwise it looked just the same.  there were less wires inside also, as all unnecessary signal paths had been eliminated
Ben can tell you exactly what was taken out.
 
Upon hearing the stripped down "hod rod" version for the first time, i immediately began to smile and tap my foot
The PRAT was significantly improved from my stock unit. The sound was more liquid, the vocals clearer, the textures more
fine detailed, the soundstage bigger, the whole system more RESOLVING and MUSICAL.
I looked at Ben and he looked and Me and grabbed the phones off my head.  He started laughing wildly, being a MAD SCIENTIST
and audio engineer, and smiled. I could hardly talk.
 
The stripped down hot rock ZOTL2 was 20-30% clearer and more resolving, kind of like the jump in performance i got when upgrading
my power supply from the stock one included to the JOULE V battery power supply.  It sounded like a new amplifier, not just a tiny
amount of improvement, a WOW improvement.
 
Ben is leaving the modified unit with me for a week why i try it out with different power supplies and types of music.
His next experiment to upgrade the actual internal components with new silver wire, capacitors, attenuator pot, etc etc etc.
I looking forward to how forward he can push the resolution of this already wonderful amplifier into the stratosphere of TOTL performance.
stay tuned....back in about ten days with more listening observations on a further upgraded ZOTL2.

 

[doctorjazz]

Blue, keep the impressions coming (though I'm afraid, as usual, your impressions will cost me some dinero)

 

[drbluenewmexico]

Blue, keep the impressions coming (though I'm afraid, as usual, your impressions will cost me some dinero)

will do! we now offer the DAY OF DOOM Zotl upgrade credit card through Bank of Mojo, or should...

 

[doctorjazz]

I'll just have to sell my family into slavery...

 

[zach915m]

  UPGRADING THE microZOTL2:   a collaborative project with Ben Z from Mojo Audio, Part One
 

 
I wonder if the Mojo Audio upgrades and other manifestations of the non stock ZOTL deserves its own thread?  I really love my stock unit and LTA PSU and am not interested in spending the time or money to strip it down and/or read about it here, but I'm sure many people may be and could congregate on a separate thread?
 
If I am in the minority others can definitely put me in my place and I'll shut it down!

 

[bazelio]

I wonder if the Mojo Audio upgrades and other manifestations of the non stock ZOTL deserves its own thread? 

 
 
Yes, it does belong in a thread to itself, IMO.

 

[doctorjazz]

I'm OK either way. Tend to dislike having multiple threads on the same gear (like LC), but I can understand if some have no interest in this aspect of ZOTLology...

 

[willsw]

I'm OK either way. Tend to dislike having multiple threads on the same gear (like LC), but I can understand if some have no interest in this aspect of ZOTLology...

Mr. Mojo has an eye for what can improve many components, not just the MicroZOTL2. He does do an incredible job of optimizing our amp, but a thread for Mojo Upgrades would leave room for some other simple improvements I know he can give regarding other equipment. I'm sure if he cracked open an LC he'd have a few suggestions.

 

[sheldaze]

I am definitely enjoying the information. I have no problems moving it to another thread to keep this one a little more (ahem) linear.
 
But at the same time, I would not want to have happen to the new thread what occurred with the Liquid Carbon thread(s), which started sprouting about one new thread every month or so of the wait. So move to another thread - sure! But please keep it in one new thread.
 
Thank you!

 

[drbluenewmexico]

I'll just have to sell my family into slavery...

PERHAPS a short term lease?

 

[MojoAudio]

Actually I have very little more to post on upgrades.
 
I'll likely post a few photos of my personal INSANELY upgraded mZ2 and leave it to the rest of you to decide what else you want or don't want on your thread. 
 
A series of upgrade posts like those takes quite a bit of my time and the main reason I posted all that was that I've been getting several mZ2 upgrade requests every month.
 
Nearly every customer that purchased one of our power supplies for their mZ2 asked about additional upgrades.
 
You'll never see me do a series of upgrade posts like those on any other forum or for any other companies product.
I'm just a SUPER fan of the mZ2 circuit and have many friends/customers that also own and love the mZ2

 
Those upgrade posts were a one time gift Head-Fi...no repeat performances...I don't give trade secrets away to just anyone.
 
If you want the people that are auditioning my upgraded mZ2 and reviewing it to start a new thread, or to only post a link to their reviews,  please let them know.
 
The other reason I posted on this thread was that I would not want people to buy "too much PSU for their system" and not be able to appreciate the performance upgrade. There are many people that read a professional review on amps and do not realize that they would need a system with an equally resolving front and back end to make purchasing that product worth their $$$.
 
I would guess that if I auditioned most of your mZ2 systems I would be recommending a source upgrade before a power supply upgrade.
 
Also, my company offers 45-day no-risk auditions on all our products, so pushing people into upgrades beyond the resolution of the rest of their system would only result in unnecessary returns that cost me $$$.  That makes no sense. We offer a 45-day no-risk audition on all our products because I would never want one of my customers to suffer from buyer's remorse.
 
Though many of you have kindly recommended Mojo Audio doing more upgrades on other products, I'm not particularly interested in getting back into that business (been there, done that). I do upgrades for my good friends, like Dr. Blue, but it is not something my company has done since 2010.
 
But since I've already opened up this can of worms, I will do mZ2 upgrades for any of you less techie mZ2 lovers that contact me off forum.
Also, if you want to discuss anything music reproduction related in detail, please contact me off forum...I'm always happy to assist a fellow music lover

 

 

[doctorjazz]

Well, I very much appreciate the posts, will be sorry to see them go. One day I may even get over my fear of soldering my fingers to the word, and make the DIY cable you described. Thanks for the interesting posts.
(I'm writing a review of the Joule v5 for Headphone Guru, and I don't want to spoil it before it appears, but, long story short, it is a worthwhile upgrade to the stock switching power supply, and to the LTA LPS (which is a good, lower cost option).