sarals
100+ Head-Fier
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- Jan 21, 2010
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miketn was kind enough to loan me his Minibox E+ and his RSA Tomahawk for a few days to help me draw some amp comparisons for a future purchase. He pointed out that the MiniBox was voiced for the Etymotic ER-4S's, and it would surprise me. He warned me that it was new, not burned in, and it would get even better with time. Still, being a long time (okay, old) engineer and (former) audiophile, I was skeptical. I've owned the Ety's for a long time and the only amps I've ever heard that could make them bloom are good desktop amps and rack mounted distribution amps in pro settings.
Mike's amps arrived yesterday and I commenced to listening almost immediately (I did have to open the box first!). I own an AMB Mini³, so I included it in my listening. I used my iPod 160G, with the LOD out, and a not expensive LOD cable that I own. Mike supplied a nice EFN LOD with his amps, but I decided early on to use my LOD. I have only Redbook standard 44.1/16 WAV files on my iPod, so that's the “encoding” I listened to. I used the Etymotic ER-4S that I own exclusively because the object was that I was “looking for” a portable amp to capably drive them.
The Setup
I inspected the amps first. I have to tell you that I had been skeptical of the MiniBox as per build quality, but it is as nice as anything I've seen. The Tomahawk was beautifully made and finished, and it was freakin' tiny – almost too small! My Mini³ is housed in a standard Hammond case, and it is bigger than the other two amps, but hey, it's not big, either! It's build quality was, well, DIY.
I did a quick listen in this order: 1) MiniBox E+, 2) RSA Tomahawk, 3) AMB Mini³.
Right away the MiniBox asserted itself. It was warm, expansive, and delivered a bass slam from the Ety's I'd not heard them do with an iPod as a source. I turned off the bass boost, and the sound softened, but the image remained expansive.
The Tomahawk was clean, quiet, and pristine. It presented a nice image, but it wasn't as captivating as the MiniBox. The bass was there, but it lacked authority and was laid back – the kind of bass I'm used to hearing from the Ety's.
The Mini³ was also quiet and clean, but it sounded a bit brash and forward, almost sterile. The image was very similar to the MiniBox, wider than the Tomahawk. The bass was once again there, but not forward, much like the Tomahawk.
After that cursory listen, it was time for the serious “interview”. Bear in mind, I am not a reviewer. I am a person who has been working in and around pro audio in some capacity (from live sound - being an A2/roadie, monitor mix engineer, FOH engineer, to small scale classical music location recording), since 1973. I don't do it full time, but I've been in love with sound reproduction since childhood, and I have a fairly well trained, good ear.
MiniBox E+
First, was the MiniBox E+. I kept the bass boost on and the gain (impedance) switch on high. I played a gamut of music through it – from E. Power Biggs performing Bach's “Toccata and Fugue in D Minor”, to Steely Dan's “Gaucho” and a lot in between. As it did initially, it engaged me with the Etymotics in a way that I had not heard them do before in a portable application. One of my first thoughts was “why did I buy those Shure SE530's, there's the bass I've been missing!”
Indeed, there was bass. Authorative, big, not overpowering, but with the kind of weight that the music posses, and that the Ety's don't normally deliver. Extension? Well, the Ety/MiniBox combination seemed to start to roll off around 50Hz. There was still bass “down there”, but it wasn't loud. There was a visceral “slam” to the music, though, if the program called for it – once again, something the Ety's don't usually do! However, that signature Etymotic accuracy was still there. The bass notes were crisp and precise, not boomy and with no overhang. The MiniBox could throw impressive dynamics, as well, and had power to spare, even at high SPL's.
The mids were “the Ety mids”, only now fleshed out. The clinical coldness the Ety's usually present was not there. Instead, there were smooth, easy sounds – liquid vocals, full sounding pianos, percussion with impact, and a warmth that was intoxicating. The notes had attack and edge and sheen, and were so luscious!
The highs were also “the Ety highs” – unchanged from what I expected to hear from these IEM's. Timbrally accurate, clean, excellent decay, and not the least bit bright or spitty.
The image the MiniBox gave was “deep, wide and continuous”. It really was! Everything was locked in place in that huge space, and the depth to that soundstage, when called for, was palpable and impressive.
My overall impression of the MiniBox E+ was one of complete synergy with the ER-4S. This amp was a window on the music, and it stayed out of the way, never imposing itself on what I was listening to (even though that was EXACTLY what it was doing – I was hearing equalized sound, but properly equalized sound).
RSA Tomahawk
I kept the gain on "high" the whole time. The batteries were fresh, brand new.
“H*** S***, this thing is little!” It did not sound little, though. It lacked the bass presentation the MiniBox had, and it also would not generate the sound pressure levels the MiniBox could. What it did do was present a clean, articulate image. It wasn't a terribly expansive image, but it was good none the less. The Ety's, with the Tomahawk, sounded like the classic ER-4S. They were every bit as precise and analytical as they were with a good desktop rig, only they were lacking in bass power. I was bothered initially that the little amp was not terribly engaging, and the more I listened to it, the more I was convinced of that. Oh, it had moments of brilliance, especially up top, where it could render very sweet highs, with lots of sparkle and the proper decay, slightly better than the other two amps – but the rest of the spectrum was not so brilliant. It tended to sound rather distant, with recessed mids and polite bass. The dynamics it threw were somewhat compressed, almost reticent. It just didn't have a lot of balls. It was becoming obvious to me that the Tomahawk and the ER-4S were not a good match.
AMB Mini³
I have had this amp for almost a week, now. It is far from burned it, it only has perhaps five hours on it. I will admit right up front that I bought it to use with my SE530's, and with them it is not quite magic, but it is very close!
However, with the ER-4S, the Mini³ is a less than perfect mate. It was better than the Tomahawk in that regard, but only because it could push the Ety's to painful SPL's. It's sound was overall very similar to the Tomahawk's, but a little darker. It had delicate highs, but with less accuracy and decay, a little bright and spitty (that may improve with more time on the amp) – rolled off bass, but with a bit more authority – and mids that were more forward in the presentation.
It's strengths were in the mids and the image. The mids were big and in your face, and very accurate. The timbre was close to right on. It also had a lot of power, and could throw dynamics like a desktop piece or a distribution amp (watch your ears!). It's soundstage was another strength, especially in placement, very, very stable. It rivaled or even bettered the MiniBox there with a wide and spacious stage, with outstanding depth and solid, stable placement of the performers.
But, it lost me in the bass. I could hear all of it, but it was rolled off and at some points, just a suggestion. Impact was there, and percussion could sound very good, but the laid back upper bass and lack of lower registers was troublesome.
It bothered me, bothered me, in the highs. The more I listened, the less I could tolerate what I was hearing. It was slightly bright, and slightly tizzy, and on some of the brighter material I threw at it – painful! I had to turn it WAAAYYYY down to be able to get through the piece of music I was listening to.
So, like the Tomahawk, it did not pair well with the Ety's.
My Favorite?
The MiniBox E+. It had it all. It was engaging, involving, foot tappin', and fun! It could play more than loud enough and still give great dynamic range, and image was huge. Where it really won me over, though, was in the voice it gave to the ER-4S – wow. It allowed them to blossom. Big, strong, extended bass, sweet, clean highs, and the best mids I've ever heard the Ety's present. IMHO, I had never heard them (except in professional applications) sound SO good. I fell in love with that amp.
All of this is IMHO. Your mileage may vary!!!
Mike's amps arrived yesterday and I commenced to listening almost immediately (I did have to open the box first!). I own an AMB Mini³, so I included it in my listening. I used my iPod 160G, with the LOD out, and a not expensive LOD cable that I own. Mike supplied a nice EFN LOD with his amps, but I decided early on to use my LOD. I have only Redbook standard 44.1/16 WAV files on my iPod, so that's the “encoding” I listened to. I used the Etymotic ER-4S that I own exclusively because the object was that I was “looking for” a portable amp to capably drive them.
The Setup
I inspected the amps first. I have to tell you that I had been skeptical of the MiniBox as per build quality, but it is as nice as anything I've seen. The Tomahawk was beautifully made and finished, and it was freakin' tiny – almost too small! My Mini³ is housed in a standard Hammond case, and it is bigger than the other two amps, but hey, it's not big, either! It's build quality was, well, DIY.
I did a quick listen in this order: 1) MiniBox E+, 2) RSA Tomahawk, 3) AMB Mini³.
Right away the MiniBox asserted itself. It was warm, expansive, and delivered a bass slam from the Ety's I'd not heard them do with an iPod as a source. I turned off the bass boost, and the sound softened, but the image remained expansive.
The Tomahawk was clean, quiet, and pristine. It presented a nice image, but it wasn't as captivating as the MiniBox. The bass was there, but it lacked authority and was laid back – the kind of bass I'm used to hearing from the Ety's.
The Mini³ was also quiet and clean, but it sounded a bit brash and forward, almost sterile. The image was very similar to the MiniBox, wider than the Tomahawk. The bass was once again there, but not forward, much like the Tomahawk.
After that cursory listen, it was time for the serious “interview”. Bear in mind, I am not a reviewer. I am a person who has been working in and around pro audio in some capacity (from live sound - being an A2/roadie, monitor mix engineer, FOH engineer, to small scale classical music location recording), since 1973. I don't do it full time, but I've been in love with sound reproduction since childhood, and I have a fairly well trained, good ear.
MiniBox E+
First, was the MiniBox E+. I kept the bass boost on and the gain (impedance) switch on high. I played a gamut of music through it – from E. Power Biggs performing Bach's “Toccata and Fugue in D Minor”, to Steely Dan's “Gaucho” and a lot in between. As it did initially, it engaged me with the Etymotics in a way that I had not heard them do before in a portable application. One of my first thoughts was “why did I buy those Shure SE530's, there's the bass I've been missing!”
Indeed, there was bass. Authorative, big, not overpowering, but with the kind of weight that the music posses, and that the Ety's don't normally deliver. Extension? Well, the Ety/MiniBox combination seemed to start to roll off around 50Hz. There was still bass “down there”, but it wasn't loud. There was a visceral “slam” to the music, though, if the program called for it – once again, something the Ety's don't usually do! However, that signature Etymotic accuracy was still there. The bass notes were crisp and precise, not boomy and with no overhang. The MiniBox could throw impressive dynamics, as well, and had power to spare, even at high SPL's.
The mids were “the Ety mids”, only now fleshed out. The clinical coldness the Ety's usually present was not there. Instead, there were smooth, easy sounds – liquid vocals, full sounding pianos, percussion with impact, and a warmth that was intoxicating. The notes had attack and edge and sheen, and were so luscious!
The highs were also “the Ety highs” – unchanged from what I expected to hear from these IEM's. Timbrally accurate, clean, excellent decay, and not the least bit bright or spitty.
The image the MiniBox gave was “deep, wide and continuous”. It really was! Everything was locked in place in that huge space, and the depth to that soundstage, when called for, was palpable and impressive.
My overall impression of the MiniBox E+ was one of complete synergy with the ER-4S. This amp was a window on the music, and it stayed out of the way, never imposing itself on what I was listening to (even though that was EXACTLY what it was doing – I was hearing equalized sound, but properly equalized sound).
RSA Tomahawk
I kept the gain on "high" the whole time. The batteries were fresh, brand new.
“H*** S***, this thing is little!” It did not sound little, though. It lacked the bass presentation the MiniBox had, and it also would not generate the sound pressure levels the MiniBox could. What it did do was present a clean, articulate image. It wasn't a terribly expansive image, but it was good none the less. The Ety's, with the Tomahawk, sounded like the classic ER-4S. They were every bit as precise and analytical as they were with a good desktop rig, only they were lacking in bass power. I was bothered initially that the little amp was not terribly engaging, and the more I listened to it, the more I was convinced of that. Oh, it had moments of brilliance, especially up top, where it could render very sweet highs, with lots of sparkle and the proper decay, slightly better than the other two amps – but the rest of the spectrum was not so brilliant. It tended to sound rather distant, with recessed mids and polite bass. The dynamics it threw were somewhat compressed, almost reticent. It just didn't have a lot of balls. It was becoming obvious to me that the Tomahawk and the ER-4S were not a good match.
AMB Mini³
I have had this amp for almost a week, now. It is far from burned it, it only has perhaps five hours on it. I will admit right up front that I bought it to use with my SE530's, and with them it is not quite magic, but it is very close!
However, with the ER-4S, the Mini³ is a less than perfect mate. It was better than the Tomahawk in that regard, but only because it could push the Ety's to painful SPL's. It's sound was overall very similar to the Tomahawk's, but a little darker. It had delicate highs, but with less accuracy and decay, a little bright and spitty (that may improve with more time on the amp) – rolled off bass, but with a bit more authority – and mids that were more forward in the presentation.
It's strengths were in the mids and the image. The mids were big and in your face, and very accurate. The timbre was close to right on. It also had a lot of power, and could throw dynamics like a desktop piece or a distribution amp (watch your ears!). It's soundstage was another strength, especially in placement, very, very stable. It rivaled or even bettered the MiniBox there with a wide and spacious stage, with outstanding depth and solid, stable placement of the performers.
But, it lost me in the bass. I could hear all of it, but it was rolled off and at some points, just a suggestion. Impact was there, and percussion could sound very good, but the laid back upper bass and lack of lower registers was troublesome.
It bothered me, bothered me, in the highs. The more I listened, the less I could tolerate what I was hearing. It was slightly bright, and slightly tizzy, and on some of the brighter material I threw at it – painful! I had to turn it WAAAYYYY down to be able to get through the piece of music I was listening to.
So, like the Tomahawk, it did not pair well with the Ety's.
My Favorite?
The MiniBox E+. It had it all. It was engaging, involving, foot tappin', and fun! It could play more than loud enough and still give great dynamic range, and image was huge. Where it really won me over, though, was in the voice it gave to the ER-4S – wow. It allowed them to blossom. Big, strong, extended bass, sweet, clean highs, and the best mids I've ever heard the Ety's present. IMHO, I had never heard them (except in professional applications) sound SO good. I fell in love with that amp.
All of this is IMHO. Your mileage may vary!!!
