Review of six power supplies with the MicroZOTL2 as they effect SQ and related listening dimensions, just completed:
FEED ME says microZOTL2
FEED ME says microZOTL2 to Power Supplies and Well Fed, he SINGS like a Champion…..
Late one night while cruising the internet I had come across the patent for the ZOTL circuit. Of course that didn’t matter since the original microZOTL headphone amps were impossible to find used…no one wanted to part with theirs. It was a legend on head-fi.org, like a ghost that some had seen but few actually experienced or believed in. In 1994 I wrote designer David Berning and begged him to make me one, which fortunately he did. My blue cased glass walled microZOTL headphone amp served me well for years (and still does) but few headphone seekers had ever heard one.
Then a couple of years ago I wrote David Berning another note, that with the resurgence of headphones, he should resume manufacturing of the original microZOTL headphone amplifier.
Recently Mr. Berning partnered with Mark Schneider of Linear Tube Audio to remanufacture and distribute a new version of the microZOTL. They kept the original ZOTL circuits intact and added a new external 12-volt power supply. They sent me a prototype to review.
Note: the original microZOTL had a switch to change to and external 12-volt battery or power supply, but hardly anyone was using that option. (although in a snarky post, Mr Berning told a great story about how you could carry it around in a backpack with a big battery and use it
to pick up girls in the park with reference level portable sound..ha…)
The new ZOTL had upgraded Russian tubes, no direct AC input, but otherwise was the same signature sound as the original. Sadly the first one came smashed in a crushed box with destroyed packing, but Mark upgraded his packing materials and quickly replaced it with a second one that was shipped perfectly safe. I plugged it in and didn't leave my headphone desk for days, listening to glorious microZOTL2 clarity through Tidal and my Mojo Audio Mystique DAC. I wrote a review of it on Head-fi.org which began “send in food, I'm not getting up anytime soon.” This was actually true.
Remember how blown away I was with the stock microZOTL2 as you read my impressions of power supply upgrades.
Meanwhile, the new microZOTL2 gradually become known to tube amp seekers, and rapidly became a hot topic on the net. DIY tube rollers sought to further juice up the amazing performance of the new microZOTL2.
Enter Ben Zwickel from Mojo Audio, a small audio engineering company in Albuquerque New Mexico, where I live. Ben heard my microZOTL set up, was totally blown away by it. He commented that it was as if he’d never heard his Sennheiser HD650s before It was the best headphone amp he’d ever heard (and he built quite a few).
Ben suggested I try one his 12-volt power supplies, on my microZOTL2 instead of the power supply it came with. I quickly agreed to the experiment. He brought over an old used Joule v1 a customer had recently traded in. As good as the new version of the microZOTL2 was with the shipped power supply, the improvement with Ben’s Joule v1 was stunning. At that time, Ben was up to a Joule v5 in his tech development, but he just loaned me this old used unit with obsolete technology just to try it out.
Powering the microZOTL2 with an old Joule v1 was a serious upgrade….something like a 30% improvement in resolution. Improved PRAT, texture, soundstage, you name it. So when Ben recently offered me to do a fairly complete test of the power supplies in the newer Joule line with my microZOTL2, I quickly agreed.
By now Ben had his own microZOTL2 amp and was loving it, and using it with his newly designed Illuminati prototype power supply to hear the development of other products in his laboratory line up as reference. How far could the power supply upgrade the microZOTL2?
We would soon find out…
Ben recently completed a prototype of a new power supply called Illuminati that will not only power a 12-volt microZOTL2, but also the 24-volt ZOTL10 amplifier. The Illuminati is a monster. I’m told the chassis will be roughly the size and shape of a loaf of bread and weigh in at about 50% more than the Joule v5. This is due to the addition of a HUGE input choke that Ben tells me not only improves performance, but cuts the crest-factor and stress on all other components in the power supply in half. Apparently the Illuminati is a fusion of a new ultralow-noise and ultrahigh-dynamic Belleson SPRU regulator (named ironically after Ben’s cat Rufus), and what Ben likes to call “big-ass old-school heavy iron.”
When designing the Illuminati Ben tells me his team went back to the drawing board so to speak on everything from the new SPRU Belleson regulator to a unique compact and highly braced/structured chassis needed to support the heavy iron. The Illuminati incorporates everything Ben’s always wanted to put into a cost-is-no-object power supply. All I can say is it is audiophile nirvana.
In addition to all the sonic improvements the Illuminati has several new protection circuits, including auto-reset Thermistors replacing fuses on the AC input and an optocoupler triggered over-current protection circuit at the final stage. Apparently the optocoupler over-current protection is so sensitive that the surge when the microZOTL2’s on button is pressed will trip it turning the dim blue “on” light bright red. Ben told me to just turn on the power switch on the microZOTL2 before turning on the power switch to the Illuminati. Aside from that, the new over-current protection wasn’t an issue.
TEST RESULTS: READ AT YOUR OWN PERIL…
For testing, I had the original power supply which came with my prototype microZOTL2, the new upgrade ZOTL LPS linear power supply that Mark Schneider is now selling as a $650 upgrade option (discounted for new microZOTL2 purchasers). From Mojo Audio I had my personal Joule v1 and Joule v2, and Ben loaned me a demo Joule v5 and a prototype Illuminati. The ZOTL power supplies were connected by a stock 12” cable. The Mojo Audio power supplies were connected to the microZOTL2 by a DC power cable that Ben developed using cryogenically treated Kimber Kable VariStrand wire and a silver plated Neutrik 4-pin XLR that mates with any Mojo Audio PSU since the Joule v2 (apparently the output connector on my Joule v1 had been updated).
I used the stock tube configurations from Mark Schneider ships with his microZOTL2..no tube rolling…new variations will have to wait for a further review (even though Ben brought over a box of his favorite NOS tubes to try out). All testing was done through my favorite Fostex Massdrop X00 Mahogony headphones which have been used for about 3000 hours and are quite seasoned.
I plugged in the prototype Illuminati power supply (est. $1,500 retail) as soon as Ben brought it over, and listened to it for about a week before I started the series of tests on the whole chain of models. I hated to disconnect it to go back down the line, because I got used the fluid fast, and musical sound it caused the microZOTL2 to reveal. But I had to to be sure it was really that good, so I went back down to the original switch-mode power supply that came with with my prototype microZOTL2 and dutifully went up the line, using the same headphones and tracks from Tidal for each power supply. The Power came through a PS Audio Duet power conditioner first, and then top of the line Audioquest power cable into the power supplies, same feed for all the tests.
Technical details how the different Mojo Audio Joule power supplies differ from each other are as follows:
Joule v1: LT1083 IC regulator, Jensen 4-pole capacitors, modest AC input filtering.
Joule v2: LT1083 IC regulator, organic polymer capacitors, intensive AC input filtering.
Joule v3: Same as v2, but with better chassis and new grounding schema.
Joule v4: Same as v3, but with original Belleson SPHP ultralow-noise regulator.
Joule v5: Similar to v4, but with output protection circuit and optional dual regulated output.
Illuminati: The only similarity to Joule v5 are the capacitors and the 4-pin XLR output.
RESULTS: there was a clear path to better sound as I went up the quality chain of power supplies for the microZOTL2. The microZOTL2 clearly said: “FEED ME and I WILL DELIVER BETTER , MORE ANALOGUE SOUNDING AUDIO.” Moreover, when I got to the Joule 5, there was no going back, the previous models and original power supplies were like low fidelity options comparatively. The Joule v5 was eminently MUSICAL and the Illuminati “worth starving for.”
Heres my notes as I progressed up the power supply line up using Tidal, playing series of well recorded songs by Randall Bramblett (blues), Dave Stringer (sacred chanting), Bob Marley, etc
HERE we go:
Stock microZOTL2 switch-mode power supply (original):
The microZOTL2 sounds good musical, but dynamics are now sound kind of flat to me. Kind of sounds like a table radio after taking Illuminati out of the system. Bass is there but limited, no impact, soundstage narrow. Tones lack decay, not musically engaging, music sounds digital.
New upgraded ZOTL LPS linear power supply:
Interestingly enough, Ben tells me the ZOTL LPS uses a similar regulator and similar organic polymer capacitors to his Joule v2 and v3. He also told me several modern linear power supplies from companies like HD Plex and YLS use a similar circuit and IC chip regulator to the new ZOTL LPS. Better PRAT, voices clearer, more emotion in songs. bass slightly better, more impact. slightly more dynamics. synths have better bite, slightly more involving, more details in music, beginning to smile again….but something still lacking…
Joule v1 :
Music more liquid now, bass announces its presence, can hear it more clearly but still not feel it much, layering improved. The dimensions and rightness, musicality improved, still not toe tapping or dancing in my chair however….lyrics are clearer, emotional communication of songs improving….better resolution…im getting happier…
Joule v2:
Musicality improving considerably, layering much better, PRAT clearly better, more details, tones purer, more analogue sounding, velvety, soundstage wider and deeper, analogue like sound replacing digital sound, toe tapping begins, blues really rocks, I yell out ‘YEAH” to favorite passages in songs….dynamics improve, begin to be exciting , I'm beginning to smile…I remember why i got into this hobby in the first place, wallet be damned…
Joule 5: WOW! WHERE HAVE YOU BEEN ALL MY ZOTL LIFE? Musically tremendously better, music coming alive. Literally, sounds like performers are in my head, or I am at live concert. PRAT EXCELLENT, dynamics tremendous, sacred music sounds sacred, JOY comes through the music immersive…I must do this upgrade (never heard the ZOTL sound like this before). The ZOTL is UNLEASHED….like its taking drugs…or having enlightenment experience….Ben's never getting this back…..
And then back to the Illuminati:
WOWWWWW. I THOUGHT THE JOULE v5 was good, but this much more subtle and refined. Drums are coming ALIVE - I play African drums so I know what live drums sound like and this was live sounding. Synths BUZZZZ through your head like ripsaws, voices are HOLOGRAPHIC. Less digital congestion, more space in the silence between notes, the music is faster, at the speed of sound, soundstage expanded where can I pawn some stuff to afford one of these?????? Wait, new it costs only 27% MORE than the Joule v5 (with optional face plate)…WHO CARES…
It cant get any better than this, my head is hitting on audio heaven….I'm hearing into the music, into the intent of the performer the communication of the song writer and performer…….like I used to get from vinyl/Apogee Diva like performance through massive Krell class A reference gear in my living room………….wait, its still the very same microZOTL2 headphone amplifier…
Well, I decided I can live with a Joule v5 performance till my winning lottery ticket arrives or my cat’s ship comes in. Apparently Ben is about to discontinue the Joule v5 and he has deals on his demos and used trade ins. But in the meantime, if you can afford it, go for the gold with new Illuminati power supply for your microZOTL2. The Joule 5 is a worthy companion in the meantime that you can be happy with, and enjoy true high fidelity heaven with the
microZOTL2 for headphones. And it also doubles as a preamp—it feeds my desktop near field Fostex subbed monitor system with aplomb.
EXCITING CONCLUSION and the moral of the story:
Moral of the story; the ZOTL demands that you feed it well. Mojo Audio has the Mojo it desires. how much Mojo you can afford and need to feel musically satisfied is up to you. There is serious science and engineering behind the upgrades in the Joule lineup they look almost the same, but they are not. Contact Ben at info@mojo-audio.com for more technical details on the different upgrade options. Since Mojo takes trade ins from customers they always seem to have some older used Joule power supply they’re selling on Audiogon or eBay.
Thanks to Ben Zwickel from Mojo Audio for the loan of these monster power supplies and to Mark Schneider for re-creating the microZOTL2, and David Berning for breathing life into it again.
Next: do upgraded Tubes make the microZOTL2 smile even more? We shall see…and hear…later on….back to listening now…..
