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Mackie

Review: Portable Amp 2 Version 2

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Construction/Ergonomics

 

The Portable Amp 2 version 2 (PA2V2) is roughly 60-70% of the size of Porta Corda II (PC2) and similarly housed in a plastic chassis. There're no legends on the PA2V2's perspex front panel as opposed to PC2's full-legend metal plate. A red LED lights up when powered on by a toggle switch. The front panel accommodates all necessary connections such as AC adapter input, signal input and output (1/8" female phono plugs).

 

The PA2V2 is lightwight even with 2 x AA size rechargeable batteries installed and solid to feel. Ergonomically, the volume pot seems slightly large although it sure makes fiddling easier than the PC2. However, the latter's pot is less prone to accidental adjustments owing to its smaller size and friction of travel. I suggest incorporating the power on/off function to the volume pot and rid the toggle switch for a less cluttered look. Another minor gripe is the 2 steel screws that appear on the top of chassis cover when the PA2V2 is upright. I would prefer to have them hidden underside or painted black.

 

Sonic characteristics

 

Here's where size doesn't matter as the PA2V2 exhibits strong gain and more than capable of powering a Beyer DT150 (my favorite monitoring cans), which is 250ohms in impedance. The test was conducted with the volume pot at 9 o'clock position. This little David is partnered with a Goliath Musical Fidelity A3CD and connected with a Canare DIY RCA-1/8" phono plug.

 

The following comments are drawn from a relative point of view with the PC2 thrown in the fray using the same setup. The PC2 is selected to run at class A operation to maximize sonic potential.

 

The PA2V2 strikes me as exceptionally open, transparent and neutral sounding. It's neither dark nor bright and I reckon there's a slight notch at the 3KHz region that results in a very smooth upper mid-range to treble and thus, devoid of sibilance. Details are of high resolution, string and wind instruments sound really articulate while projection of ambience (space) around each instrument and decay are clearly the amp's forte. The PC2 sounds muffled by comparison but it has a smoother and fuller mid range than the Pa2V2. Vocals can sound very slightly grainy at times and perhaps recessed (subjective) with the PA2V2. I personally think the PA2V2 is quite close to neutrality from mid range and up.

 

Bass is where the PC2 excels over PA2V2. Using a home theater calibration disc, the former starts to roll off around 50Hz but earlier for the latter at about 63Hz region. Bass depth is also shallower with the PA2V2 which becomes inaudible (to me) at 28Hz while the PC2 scores better at 25Hz. In fact, I can hear a very soft rumble at 22Hz with the latter but it could be placebo effect. 3Hz may seem miniscule but each Hz lower in the low bass region is a challenge for even a full range power amp, let alone speakers.

 

Although the PC2 gives better slam and weight with hip-hop/R&B/pop-rock genre, the PA2V2 defines bass notes better (less lumpy especially with double bass/cello) and its tightness also contribute to perception of speed and attack, much akin to that of a Grado SR80 which is also included in this test.

 

Lastly, soundstaging/imaging is remarkable and the excellent presentation of depth and width is a boon to close design headphones and contributes to a less claustrophobic experience. In this respect, along with the overall high level of transparency, clarity and neutrality (aside from bass regions), I reckon the amp's maker carries an agenda for audiophiles during the course of design.

 

What about the amp's suitability with low impedance cans such as a 32-ohm Grado SR80 and Beyer DT440? Here's where the high gain and/or potentiometer create a bit of havoc. With these cans, it can get quite loud with the volume pot at 8 o'clock and any attempts to turn it lower at and below 7 o'clock may result in a very slight imbalance in channel separation. However, this detriment is much less pronounced when the amp is partnered with a portable cd player and the likes as signal strength is lower than that of MF A3CD player (2.3V). Rest assured the same merits are prevalent when the PA2V2 is hooked up to a good quality portable source. Incidentally, I find the Grado and PA2V2 have something special going (synergy) as they exhibit similar sonic characteristics. The amp shows much bite in guitar riffs and ups the ante in details and transparency. Therefore, the PA2V2 is equally at ease with classical, acoustical, jazz, vocal and rock genre. The PC2 suits hip-hop, R&B, trance music lovers better although it's also competent with the aforementioned genre.

 

Practicality/Suitability

 

The PA2V2 is a portable amp and must first perform its primary role to users out on the streets. It's capable of driving any headphone one is sane enough to wear on the go but the audiophile merits could be lessened or even negated if open cans such as Grado are used. I would highly recommend open design for indoors and close ones for outdoors. The PA2V2 simply expands the airspace (if you're an airhead ……… kidding) between your head and makes close cans sound so much roomier, every nuance clearer and bass more reinforced.

 

Conclusion

 

I may not have listened to all portable amps available in the market but I'm certainly impressed with the PA2V2. Based on the aforementioned comparison with PC2 and from memory, Xin Supermini and Supermicro, the PA2V2 strikes me as an audiophile portable amp in the first few instances. However, garbage-in garbage-out applies and fed with a weak source or used with open cans in a noisy environment, the amp's aforementioned merits could be severely negated. A major plus point of the PA2V2 which retails for around US$70, simply multiplies music enjoyment by many, many folds with this purchase. Best Buy and yours truly has already ordered one!

 

Equipment/Accessories used

 

- Musical Fidelity A3CD cd player

- Portable Amp 2 version 2

- Porta Corda II

- Canare DIY RCA-1/8" interconnect

- MAS Power Master power cord

- Goldmund cones

- Cyrus Isoplat

- Beyer DT150

- Beyer DT440

- Grado SR80

 

Test CDs

 

- Die Rohre - The Tube

Stuttgarter Kammerorchester

 

- Patricia Barber - Nightclub

- Diick Hyman - Swing Is Here

- Tsai Chin - Golden Leaves

- Avril Larvigne - Let Go

- Radiohead - OK Computer

 

Reference links

 

Homepage

Ebay sales

 

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Edited by Mackie

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Excellent. Just what I wanna hear! Sorry for pushing you to do this review but it's gonna make lotsa ppl and Gary from electric-avenues happy. I'm gonna order one NOW!

 

Thanks for the great review. Otsukare! holiday.gif

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Thanks Mackie for the interesting read. I have no need for a portable amp at the moment, but just for interest's sake, how would you rate the "value-for-money" factor of this amp compared to the PCII? And what happens to your PCII when the "new kid on the block" arrives? (My bdae is ard the corner btw *Hint* *Hint* tongue.gif )

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Absolute0, I'm surprised U asked this question. The PA2V2 costs US$70 with AC adapter and Gary is likely to shave a few dollars off as the adapter is only meant for US power standard. Conversely, PCII costs US$225 although its incorporation of crossfeed circuity is a real boon.

 

I intend to sell my PCII if anyone is interested but I avoided posting an ad before the review to avert any conflict of interest.

 

Your birthday har? Pm your wish to me and gor gor will try to make it come true. tongue.gif

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Mine is on the way!! Woo hoo! Actually guys, dunno if i should do this but by e-mailing Gary through his website, you can purchase directly, without bidding, AND it's cheaper! I'm getting mine at US$60 (shipping inclusive) because I chose not to purchase the adaptor.

Edited by Gahman

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Affirmative. Please email him direct for the amps. In any case, the ACV adapter is not suitable for UK power standards and thus, the lower price.

 

I'm also honored to announce Gary intends to send future versions/prototypes for my assessment. I will pass on my opinions to U chaps of course.

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Your birthday har? Pm your wish to me and gor gor will try to make it come true. tongue.gif

Serious? laugh.gif

 

Anyway I asked that question because the PCII is pretty highly-regarded, so I wanted to know for sure that the PA2V2 has surpassed the former in terms of price to performance ratio.

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Affirmative. Please email him direct for the amps. In any case, the ACV adapter is not suitable for UK power standards and thus, the lower price.

 

I'm also honored to announce Gary intends to send future versions/prototypes for my assessment. I will pass on my opinions to U chaps of course.

Yes, the AC adaptor supply Gary supplied does not work with our voltage. But beware when u purchase the adaptor in Singapore as the amp requires a mini jack as ext input and so far I see not all adaptors selling out there provide this small connection so please be careful. The adaptor should supply 3V and 200mA. Higher mA should be OK but if too high may damage the NiMH batteries inside the amp when charging with the amp off.

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Congrats. You should be having fun today eh? Now....where's mine?...It's been a week and...maybe tomorrow! haha...Can't wait too! kicking.gif

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