REVIEW: Fixup's SuperMacro

[Zanth]

It has been a long time coming and I finally have had a moment to formulate my impressions regarding a new little and much anticipated amp – the SuperMacro. Once termed the SuperMono, Fixup has very recently changed the name to SuperMacro. This unit actually reads SuperMono, and I have had it just over a month, so this is a very recent change.

Why the change? The answer runs a little personal for Fixup, but the short of it is that Xintech and Fixup were two autonomous entities, Fixup providing all the R&D and Xintech mass producing the SuperDual (originally called the SuperMono, not the same amp under review here) are parting ways for reasons that will remain undisclosed here (mostly because I know only parts of the story and frankly it has nothing to do with this new amp nor Fixup’s capacity to produce them). Suffice to say, the SuperMacro is NOT the SuperMono/SuperDual, a new name means that Fixup may have a certain legal freedom to perhaps get these amps out earlier than expected. Originally the amp was slated for an October 1st release had Xintech closed its doors. I’m not sure of any recent developments but since it is not being publicly advertised on Fixup.net (one is able to locate a pre-ordering page but it is not easily found as far as I can tell) I’m assuming the general public will have to wait just a bit longer until they can get their hands on a unit.

About a year ago I was privy to one of Fixup’s earlier models, the SuperMini 5.1. The sound was good - crisp, resolving, with a nice tone and enough juice to power the portable phones I usually use (Koss KSC-35’s and Etymotic 4P/S). I did not test this amp with any of my Grados but I was told that the amp did marvellously well with an Alessandro MS-1.

This past summer my curiosity regarding some new portable amps was increasing almost daily. When I speak about portable amps I mean ones that I can transport to work or to school (I have an office there too). I was very excited to have something small yet with a nice sound and enough juice to drive any of my phones. I usually have a PCDP in my lab or office and have historically just used my headphones unamped. I do own a CHA47 masterfully built by JMT, but this little guy sits on my nightstand under yet another PCDP. It is part of my bedroom setup which, until recently, has seen the most use of any of my rigs. That said, I didn’t want to have to pack this amp up every morning and then set it back up at night. Call me lazy, I don’t care. It is enough of a hassle for me that looking into another amp was rational. I mean, come on, let’s face it, this is Head-fi! Multiple amps call to us…the sin of gluttony and the high cost aside, I want one of each

Initially I was looking at anything portable, with a exceptionally small footprint, but then I got to thinking…hmmm, why not look at something mobile as well? I have been quite interested in Sony’s new HiMD technology, yet the DRM and the lack of MP3 support has been bothering me, that and the scarcity of the media meant I would perhaps look elsewhere. HD DAP’s have also tinkled my fancy. Certainly the iPod is very sexy but it is pricey and doesn’t play Ogg or Flac. The Rio Karma does though…but there have been issues with these players so I waited and continue to wait on my new portable player. Will it be a future HiMD unit with natant MP3 decoding? All the Toshiba chips used in the players are by their nature, able to and simply rendered incapable by Sony. Now that Sony has come around to MP3 (at least with their upcoming HD DAP) HiMD may be enticing, but not yet. Then there is the upcoming Rio Chroma. Supposedly quite small, much slimmer than the Karma and with 20 or 30 GB capacity! Oh and it will play Ogg and Flac. Sweet! Hopefully this unit won’t have the quality issues the Karma was plagued with. So what is my point? The point is my desire to have a sweet mobile amp to partner up with a high quality DAP increased and continues to increase as I anticipate my new mobile media player. My wife owns a nice mini-meta, we have a CMOY in a really small case as well, but given the praise of the Emmeline SR71 and my memory of the good sound of the SuperMini 5.1, I felt that my ears should turn their attention toward a new, minute and top quality unit.

I contacted both Fixup and Emmeline and requested a SuperMono (so called at the time) and a SR71 respectively. Both agreed to send me a unit to audition and review. The SR71 will be on hand a little bit later and I have high hopes for it given the nearly unanimous praise.

My excitement for the SuperMacro was quite high. For one, the size was said to be incredibly small, the smallest of the high quality mobile amps AND it has the option to use AC. As I stated above, I was initially interested in what I call a portable amp. I wanted something I could use mainly at work in my lab or at school, in the library or in my office. I wanted something that wouldn’t necessarily require that I go out and buy a load of rechargeables or continuously spend big bucks on regular batteries. The SuperMacro certainly fits the bill.

So as per usual, these are my impressions of this amp. Take them for what they are worth.

(Hats off to Bangraman for his recent review of the A.N.T. Amber amp, I’m going to mimic his format since it is quite suitable for this preview)

The amp was designed and made in the USA and all future amps will be made here too. I believe some mentioned that they will be or were going to be made in China. Perhaps the Xintech amps were made in China, but not the Fixup amps. All parts are from well-known electronics stores: Digikey, Mouser and Newark.

External Build

Right away one will notice the minute size of this amp. Not quite the size of a credit card and about an inch high. The unit weighs less than 7 oz. with 8 x AAA’s. Not too shabby at all. I actually like the weight. The unit is compact and feels solid. In fact, I dropped it this morning without apparent harm. I am quite pleased with this. Initially I felt the volume knob extended far too much and was an eyesore. However, once the mono cable is plugged in, the connector will extend out past the knob revealing that the entire “in-use” look is quite fine. Bare though, the knob is simply out of place next to the miniscule switches. Regarding the switches, when I mention they are miniscule I mean that. They are so small that if one has large hands, the switch size could be an annoyance. Some patience and logic will permit ease of use and fair access to the features yet on the go, I’m sure this will put some off. For example, the power switch sits right above the headphone input. The AC input sits right bedside the power switch. If the headphones and walwart are plugged into the amp, one will have a very difficult time getting at the switch. Even with the AC input, when using Ety’s, I have a tough time turning the amp on and off when they are plugged in. So what I tend to do is turn the amp on and then plug the headphones in. When turning off the amp I just displace the Ety’s a fraction from a firm fit and I’m able to set the switch to off. This is likely the only seriously negative comment I have regarding the amp’s ergonomics. To me it is not a big deal, but for some it could be.

As one can tell from the pictures, this amp comes with 5 switches. (PICS will be up tomorrow) I felt that it would be best if I review an amp with all the features. My reasoning was twofold – first, if the amp sounded good with all this in the signal path, then imagine how great it would sound with minimal options and second, I wanted to be able to comment on the sound with each option enabled. The middle switches are easily accessible but the Gain and Bass Boost are a bit obstructed by the mono jack. These are far easier to deal with than the power switch however. I did ask Fixup about the possibility of push buttons for the power and the other features and he replied that he could not find any small enough and functional within this unit. I’ll take his word for it. Again, it is not an “end of the world" issue and the small form factor, as well as the solid construction, will likely offset the opinion of most folks on whether or not to try out this amp. Of course, the sound should be a primary factor but more about that later.

Some have voiced their opinion regarding the screws at the back of the unit. They do extend out as one can see in the pictures but I don’t find them a hindrance in any way and moreover, they work as thumbscrews for me. This way I don’t need to carry around a screwdriver while on the go to swap batteries.

These are minor cosmetic quibbles and my aesthetic desires are far outweighed by the tasteful colour, the small form factor, durable exterior and what in my mind is excellent craftsmanship. The case itself is anodized and engraved aluminum with no sharp corners to scratch that spanking new iPod many of you will undoubtably use with a SuperMacro.

Though my unit is a prototype, it was built to production spec and thus it could only get better from here.

Internal Build

Fixup is top tier, there is no doubt about it. Noone is able to design and build smaller circuits (with a human hand up to now at least). The soldering is top notch and it is neat and tidy in there for all you OC freaks out there. Since I’m not an EE I am not going to pretend to know anything about the insides except from what I have been told. Suffice to say, it looks first rate to me!

Technical Details

The technology inside the SuperMacro is really something to admire. Here are the specs of the switches:

DC-in jack + in-amp battery charging (remember to unscrew the back of the amp when using regular batteries and the walwart)
Auto-off timer
Auto/manual battery-save mode switching
Impedance matching switch (0/75 ohm impedance) optional
Gain adjustment switch (11/21) optional
Bass boost bypassing switch (0/10 dB) optional
XinFeed bypassing switch (0/1) optional

Likely the most interesting aspect of these multiple options is that they are all implemented on a separated board! There are actually two PCB boards tucked inside there. Incidentally, when implemented, these options should add minimal side effects, if any at all, to the main amp board. Furthermore, these features can be fully disconnected or not implemented at all, for those who want the purest sound and/or don't need these extra features.

Other feautures:

The amp I have on hand uses the acclaimed OPA637. I enjoy a very accurate and punchy sound and the OPA637 is said to be linear, fast, with lots of snap. I went with this option vs. the stock OPA134, which is said to have a warmer and fuller sound.

This version of the SuperMacro is thus optimized for the OPA637 whereas all future amps will be optimized for other OPAMPS (permitting easy swapping) including the stock OPA134 and the upgraded OPA627 and AD8610.

Very recently the OPA637 was eliminated as an upgrade option due to the lack of internal compensation, which the other OPAMPS enjoy. The idea was to facilitate OPAMP rolling and to keep the cost of the unit down. I am told that a DIYer could get some OPA637 samples from TI and give it a try. For some, depending on the phones used, the OPA637 is said to come off a bit bright. I don’t find this at all in my amp, but I digress, more on that later.

This amp uses the BUF634 diamond buffer in a triple stack configuration. The three buffers are an option while a 2x buffer config comes stock. The BUF634 can produce more than enough current (250 mA) for Etys, but its impedance is quite high (15 ohm). There are two ways to lower the impedance: either using a high current (which my Grados love) and wide bandwidth or stacking up multiple buffers. The SuperMacro implements both methods - it works at high current with a wide bandwidth while remarkably remaining battery-friendly as well as coming stock with the 2x buffers and 3x as optional, as already mentioned.

Some benchmarks for the single buffer with the OPA637 using Ety ER4P’s are as follows:

F/R: +0.02/-0.12
N/L: -105.1dB
D/R: 105.0dB
THD: 0.0005%
IMD: 0.0019%
C/T: -95.0dB

Examining the ratings one notes that the amp was tested to have extremely low distortion (0.0005%), noise (-105dB) and channel crosstalk (-95dB). I've personally not witnessed amps that are close to these numbers and yet the amp does not use an increased feedback as compared with similar amps such as the XP7 and PPA to achieve these exceptionally good numbers.

Heavy feedback does provide for very good numbers, but this can hinder the sound. Some amps use less feedback (such as the Gilmore Discreet amps), but the tested numbers are not as exceptional (yet many feel these amps are the best SS amps on the market today, thus numbers don’t mean everything). Some amps give good numbers only when driving high impedance phones such as HD-580/600/650 (300 ohms) yet will post poor numbers when driving low impedance phones such as Grados (32 ohms) and the Ety ER4P (27ohms).

The SuperMacro may be the first amp in history to provide such high benchmarks
(almost at the limit of the test equipment) without using heavy feedback, even when driving low-Z phones yet still providing >250mA current at >12V.

This was all made possible by using a simple circuit with some miniature magic, tricking the amp way out.

First, the virtual ground plays a very important role here and was apparently very difficult to implement. The key was using only those OPAMPs that have very low output impedances, thereby avoiding high levels of crosstalk. If an open-loop buffer had been used on the ground channel, the crosstalk would have been high. The OPAMPs must also have a very high current output (>100mA); otherwise, the distortion will go quite high at high power output levels. OPAMPs that qualify according to the above requirements are usually current-feedback types, with very high speeds and frequencies. The instability of these amplifiers must be dealt with, stabilizing them by carefully choosing the feedback resistor value, and carefully laying out the PCB and power supply bypassing.

It is interesting to note that some folks have criticized the Grado RA-1 circuit for being overly simple, or even more recently the new (and highly acclaimed) Emmeline SR71 (which Ray Samuels has since laid to rest the rumors that it is a META clone, when in fact it is very similar to the sample circuit of the BUF634's datasheet). According to Fixup, the best amps (which many of us have already realized) are those that use a simple circuit (like the SuperMacro and the SR71) with quality parts in a very logical and clean PCB layout. Apparently Fixup went through many versions until settling on the present board layouts.

The power supply bypassing is a unique system. The virtual ground bypassing is totally different than bypassing two real power supplies since the virtual
ground does not return. Making it return would have driven the distortion way up because the high current would have interfered with the input reference. The ground traces were carefully placed, to ensure the lowest channel crosstalk and distortion. This is considered the most important feature of the PCB and the hardest to implement. The traces for L and R channels were also separated as much as possible permitting the -95dB crosstalk (while driving a 27 ohm load) and 0.0005% distortion. Compare these numbers with most amps at -70dB and 0.01%.

Source impedance matching (SIM) was also carefully considered. If not matched, the distortion can go as high as 0.02% - say bye bye to the 0.0005%. Interestingly, the OPA637's SIM is very different than the other offered OPAMPS and is the reason why the amp can’t be optimized for all the OPAMPS. This was the driving factor to eliminate the OPA637, and apparently an optimized SuperMacro using the OPA627 is as good or better (subject’s tastes considered of course) than the optimized OPA637 version. Another important note is Walt Jung's multiple loop feedback (MLF) does not work well when the output buffer is open loop like BUF634 and as such the MLF does not work for OPA637.

Finally, some amps use Class-A biasing for OPAMPs. The SuperMacro does not. The reason is that if one biases to the wrong rail (+ or -), then the sound gets worse and it is difficult to know which rail is right for a given OPAMP sincee the internal circuitry is rarely if ever, available. Fixup decided not to do it at all in order to secure a higher fidelity.

So how can all of this EE goodness get inside such a small amp? Well, for the first time, Fixup has decided to go with a larger case. But don’t think the case is chock full of electronics, no sir, remember, 8 AAA batteries are fit into the back of the amp (which btw, have let me enjoy music for over 20 hours thus far with no degradation in sound). Insane to say the least.

Though sound quality is subjective, the technical finesse of this amp is not. Objectively, this amp is something unique in design and especially in implementation. In fact, this amp is revolutionary in many ways. Fantastic and a two thumbs WAY up for these qualities.


Sound Quality

Ahh the meat. This is the reason we are all here. We want to LISTEN to our music. Good good, I’m right there with you. Team Source first, Team Headphones first, Team amps first, all of you step aside, I’m all over Team Music first. Of course, from what I know of current technology, headphones, amps and sources are kind of important in um…well, listening to music (live musicians willing to follow me around and remain inconspicuous in my home, my lab and my office MAY apply. N.B. I don’t have money to pay you).

As per my usual routine, I let the amp burn in for about a week. I had my PCDP on repeat and let the amp (running with the walwart) run with some cheap stock ear buds I keep on hand.

I primarily used Etymotics 4P’s and Koss KSC 35’s and a PCPD or my MD player to review, though for kicks I did hook the amp up to my main cd player and plugged in the RS-1’s and the HP-1’s.

Bangraman is quoted as saying that the SuperMacro provided a remarkable clarity to the music, in fact, I agree 100%. This is perhaps the strongest attribute of the amp. Many feel that using an amp for a mobile system is a waste. Perhaps this is true for poorer sources or for headphones that don’t scale very well. In my opinion however, this amp does very well with even the KSC 35’s which I feel are not the greatest in the scale department and in fact, I rarely if ever, use them with an amp. 99.9% of the time they are used straight out of my Sony MZ-S1. This combo works very very well for me, does what I want it to do while minimizing bulk. However, when I’m at work or school, I’m stationary, usually reading/studying/thinking or writing and I enjoy higher quality sound. So an amp is required.

Straight from the portable using the Ety 4P’s, the sound is clear, resolving, extended and linear. It is the typical Ety 4 series signature sound yet when adding an amp into the mix the headstage is widened, the bass becomes heftier and the highs take on a more refined sound. The Ety 4P’s can sometimes come across as slightly sibilant in the top end. The 4S does not seem to exhibit this in the least. Historically I have used the impedance cable from Fixup to convert the 4P to a 4S yet this cable is no longer necessary with the impedance switch on the SuperMacro. From here on in my impressions will be based on the use of my PCDP with the Ety 4P, impedance switch enabled, unless otherwise noted.

The high current and wide bandwidth must have something to do with the remarkable clarity and impact the sound possesses. I have always felt that headphones can do well enough unamped but they will only come into their own when they are properly powered. Loud volume does not equate to properly powered. Adequate power will provide a wider soundstage, a wider headstage, taut and powerful bass, sweet clear and refined highs with good instrument separation and an overall magic that will send one into a sombre, blissful euphoric state (well maybe not everyone, but certainly me). I had stated in the past that the best I had ever heard my Ety’s perform were with the original Headamp Gilmore V2. I have since found a new headphone amp that surpasses this amp, and it is the SuperMacro. I evaluated the sound using batteries primarily and not once did I feel the sound suffered compared with using the walwart. In fact, the background was blacker using the batteries (an expected result) even though the background was already blacker than any I had heard previously.

Highs

The Ety’s unamped took on a dirty and shrill characteristic, which was completely eliminated using the SuperMacro. Instead, extended and smooth highs abounded. That peaky sound some folks have mentioned, was entirely absent and in its stead, especially with a triangle or cymbals, a crisp vibrant sound was heard, energetic and fast with enough sparkle to keep one interested in the sound but not overbearing leading one to pay too close attention to this type of artefact to the detriment of the other ranges. Switching the impedance back to 0 ohms or popping up the gain which nearly negated the benefits of the impedance switch (P to S), the sound was more forward, brighter and a bit dirty and shrill. I found that the highs demonstrated the greatest separation in quality between the P and S. The 4S is simply a smoother more liquid and more refined phone than the 4P. This will not go unnoticed even to untrained ears. The 4P’s grain seems to overly accentuate sibilance and the peaky highs. As an S, the sound is extremely pure sounding, like comparing mineral water to distilled water. They are both water, nice and clear and refreshing, but side by side, sip by sip, one is immediately drawn to the presence of artefacts in the mineral water: electrolytes, minerals (duh) a near “dirty” taste compared to distilled water. I myself only drink distilled water (at least when I have the choice). Given the choice here, I choose my distilled water, my 4S sound. Implementing the Xinfeed I didn’t notice a difference in the sound. I am told that crossfeed takes time to adjust to and notice. It is subtle but does help with distinctive right-left tracks. I was using batteries, Xinfeed eats up more energy, I didn’t use it after my initial test. Perhaps as I continue to evaluate the amp, I will try out the Xinfeed more and more.

Mid-Range

The oh so cherished mids. Ety’s with their phenomenal and what some even call “hyper-real” sound is especially apparent in the midrange. I feel that the midrange is the spot that is least changed by swapping amps. Though an amp is definitely necessary when using the 4 series to get the most out of the phones, and this is true for the mids, once an amp is introduced, one with enough juice to make a difference, I feel the control is nearly the same across the board. What is noticeable is the instrument separation and the staging along with the colouration an amp inevitably imparts. I feel that the SuperMacro is the single most transparent amp (in this configuration – OPA637 + 3x buffer) next to the Headmap Gilmores. I’m confident that the reason it falls short is the presence of the OPAMPS, this is the difference between a discreet and an opamp based amp. Nonetheless, the sound was vibrant, and quite linear with the leading edge of the notes performing at quite a slightly elevated level compared to the Gilmore Lite. Incredibly enough, it was the decay of the notes that impressed me the most in this band (and the bass region). Ety’s are renowned for being quick, critically, one could say they are artificially fast and don’t provide the proper decay of notes, leaving the sound thin and at times boring and fatiguing. The SuperMacro provided the Etys with whatever they needed to sustain a note just a bit longer, enough to take notice, but not enough to fall of one’s chair and cry out in excitement. This is not the fault of the amp, but simply the shortcoming of the phones. For this reason and the possibility of a comfortable side sleep position with the Sensaphonic 2x-s’ has me contemplating a divorce from my cherished bedmates. However, and I want to really emphasize this, I have never heard the Ety’s sound as good as they do, than when I use the SuperMacro (impedance set at 75 ohms and bass boost set to 1) and I even mentioned this and stated it had curbed my desire to migrate to the 2x-s’. Then a fellow Head-fier informed me that what I wanted most of an IEM would certainly be found in this new phone, usurping my love of the Ety’s. Wallet’s pulse permitting, I’ll have some early spring to find out.

Bass

No matter what one does, the Ety’s will never sound like full-sized headphones, especially in the bass region. Do you want Beyer Bass? Keep looking. You won’t find it with this combo; however, I have always appreciated the articulated, deep and resovled bass of the Ety’s. With the SuperMacro (bass at 0) the sound is familiar, certainly the notes have more oomph to them, a more solid, palpable sound. Of course, these Ety’s weren’t shy in this area, but I would never classify this area as their forte either. I still wouldn’t but I would not say they disappoint, nor should the Etymotic engineers be embarrassed because they achieve a refinement nearly untouched by any transducer in the world. That said, when the bass boost is set at 1 (+10 db), the sound warms up, the decay is even longer (this could be bad for phones like the KSC 35 which are already pretty heavy in the bass, though bumping up the bass boost gets the trance tracks way up there and me tapping my foot at my desk, what more could one ask for?) and the notes have a new found weight that has startled me more than a few times. On drum-heavy tracks the bass drum really comes through, layering well with the clear highs and beautiful midrange. I have since kept the bass boost on and never looked back.

Other Configurations

Evidently, my intension for a mobile amp, was to use it with the Ety’s. That said, for kicks, I wanted to determine just how well this amp performed with my full-sized cans. I hooked the amp up to my Shanling CD T100, popped on a 1/8 -->1/4 inch adapter and plugged in the 32 ohm Grado RS-1’s (flats of course).

What my ears heard was nothing short of spectacular. The sound was fuller and more solid than when I listen with the RA-1 (this is with the gain switch at 11 and the pot at 8:30-9:00, if the gain were set to 21 I could not even move it a nanometre past 6 before I went deaf). The bass was tighter and deeper too. This is without the bass boost. I did not try with the bass boost as I felt the bass was good enough without. Too much of a good thing is well…too much! The grain that is sometimes noticed while listening with the RA-1 was also absent. In fact, in every way, the SuperMacro outclassed the RA-1, well in almost every way. I found the RA-1 had a better sense of PRaT than the SuperMacro and there was this subtle magic that seemed to be missing with the new combo. I know I know…I’m dreaming in technicolour, or listening in it. The RA-1 does not have magical powers with the RS-1. There is no synergy. Well, if one can’t hear it, too bad for them, they can buy another amp. I hear it, psychosomatic or not, and frankly, I’m fortunate, as I own the darn thing. Would I recommend the RA-1 over the SuperMacro if the amp was going to be the sole amp in a system? I guess it would depend on what the listener wanted out of sound, overall I would suggest the SuperMacro since it permits mobile use and has so many cool features. It is also cheaper ($300 fully loaded, $200 base model).

So it can power, and well I might add, the RS-1’s, but what about the HP-1’s? Even though they only have an impedance of 40, it seems the HP-1’s need super current from an amp before they can really sound great. Many many many folks have stated that the HP-1’s are boring phones, that is until they listen using a Melos (preferably modded by carlo). All of a sudden they see the light and their realization is that few if any setups can match the one above. Does the SuperMacro have what the HP-1’s need? In a word – YES! In fact, the only other amp I have felt powers the HP-1 better (other than my own Melos, modded by carlo and tuned ever so well to the HP-1’s) is the Headamp Gilmore line. Remember, this was using batteries! The sound was very refined, linear, punchy (which the HP-1’s excel at, but only when driven properly) with ample amounts of bass. The highs weren’t as extended as with the Melos, nor the Gilmores, but the SuperMacro was certainly not shamed by them. One must note the end of this little amp and the end of such full out amps as the Melos and Gilmores. One really nice thing about the SuperMacro was how quiet it was using both sets of Grados. Admittedly, the RS-1’s are more sensitive than the HP-1’s, and when using the Melos with the RS-1’s, I can hear at 0 volume very quiet but still audible hiss. This is entirely absent with the HP-1’s. Using the SuperMacro, both phones emitted dead silence at zero volume and all the way up to near max level (at which time the amp started to distort – using batteries).

Conclusion

This amp is tiny and a jack of all trades. But is it a master of none? No, I think it is a master of a few things. It is certainly the highest quality portable amp I have ever heard. Whether considering build or sound quality. I have yet to set eyes on an Emmeline SR71, but even if the Emmeline takes it for build or sound, I’m certain the SuperMacro will come close, if not surpass it. But this is conjecture, hopefully soon I will have some concrete results.

I feel the SuperMacro mates well with high end rigs while outclassing lower end sources and headphones. My portable cd player was certainly the bottle neck in the chain and when I moved to a lengthy audition using my main cd player, the merits of the SuperMacro were ever more apparent. The linearity of the sound is surpassed only by its clarity and control. Though, perhaps I misspoke, the black backgrounds are cleary beyond anything I have heard and when using Etymotics, this is a Godsend. My tastes don’t require the gain switch nor the crossfeed, but I would not be without the impedance switch and the bass boost. Both options provide wonderful sound with Ety’s that is unsurpassed in my experience, even with my Melos (though perhaps my Melos could come close if not surpass it if only the amp was quieter with the Ety’s, but as it stands now, it is no contest). Would I use this as my sole amp? If I had to, yes. Would I recommend it as a home unit? Yes, if one doesn’t mind getting at the power switch with the walwart connected to it. Do the batteries provide enough power for a variety of phones? Well considering I have, in the past, found the HP-1’s to be the hardest phones to drive (I have no experience with the AKG K1000’s) then yes, since it drives them well, I figure it will drive the HD 650’s and other phones equally well.

What are some highlights of the amp? Well the fact that it powers off after 90 minutes of no signal (walwart of batteries) is a feature that is AWESOME for folks on the go who may forget to shut off their amp. Many portable players have auto-shut offs but no amp that I know of has this feature. The middle setting for the power switch activates this feature and it works like a charm. Another cool feature is the powering of rechargeable batteries when plugged into the wall! In this way, one never have to worry about battery replacing unless one is headed on a 24 flight (remember that after 20+ hours with these batteries, the amp is still going strong)

In summary, at an incredible price of just $200 for the entry level amp (OPA134 + 2x buffer) one is offered a pure sound, with the convenience of a mobile amp with the quality sound of a full sized amp. The middle level is priced at
$250, it does not have the 4 feature switches, but users can roll opamps and
stack up buffers, to get the best configuration they like. The top level
is priced at $300 and comes with all the features found on the reviewed amp, minus the OPA637.

I never thought I would want to carry around an amp while on the go, but having lived with this amp for a month and a half, I couldn’t imagine my bus rides without it. And my long study sessions? Please, listening to near endless hours of dronology has never sounded better.

Kudos to Fixup for developing such a quality amp. Folks, I think we are in the golden age of amps, can it really get any better than what these new and wonderful manufacturers are throwing at us? If so, I’m not sure my temporal lobe can handle the musical goodness!

Associated Equipment
Panasonic Shockwave SLSW870 PCDP (Darth Maul Colouring)
Sony MZ-S1 Minidisc Recorder
Shanling CD T100
Kimber Mini to Mini
Kimber Mini to RCA
Melos SHA-X
Grado RA-1
Grado HP-1
Grado RS-1
Etymotic 4 series
Koss KSC-35

Music - variety, about 60 discs, all genres but heavy rotation of ambient, dronology, jazz, and classical