I've been at this all morning and I have to confess at this point that I've bitten off a tad more than I can handle in a single review. I think it best to do these comparisons in smaller, more digestible chunks. With this in mind, I've decided to begin with a comparison of the META42 portable versus the SuperMini v6.
The sources used were the new generation 30 GB iPod and a Sony EJ1000. All tests were performed using the PCDP's line-out and the headphone out of the iPod. (More on this decision below.)
The headphones used were HD600s, DT880s, D66s, Ety ER-4P/S and CD3000s. The HD600s are fitted with a Sennheiser 1.2 meter cable. The Etys have FixUp's replacement cable, 4S adapter, and the standard foamies. The other headphones are completely stock with no tweaks of any kind. This isn't a headphone face off, but I feel those I've selected for the test to be representative of the most widely owned models here. The idea is to determine their relative suitability for use with these particular amp/source combinations. Since the HD600 appears to be the most widely experienced quality headphone on Head-Fi, I decided to use it as the test reference.
The amps were configured as follows:
The META42 is a KurtW version, and full specifications are listed at the end of this article. For this phase of the testing, it was used without its external power supply. The full specs are listed below.
The SuperMini v2 included the standard attached six-inch OFC cable and standard power indicator. This has been my workhorse iPod amp and has seen more use by far than the others combined.
The SuperMini v6, like the v2, was purchased solely for use with the iPod when driving difficult 'phones. It is an analog version with crossfeed and the optional power indicator.
The ICs were Straightwire, Kimber PJB and Xin's OFC.
The music used consisted primarily of a jazz mix including Benoit, Sinatra, Krall, Jones, Garrett, and several others. The classical selections included mostly small ensemble pieces for cello, violin, viola, flute, and piano. Where the iPod and PCDP were compared, the rips were all 160kbps AACs.
The Tests.
First up was the Kimber--HD600--META42--EJ1000. Then I realized that wouldn't work so I tried EJ1000--Kimber--META42--HD600. (Just kidding, fellas!) There were no surprises here. The META, like always, quickly made me wonder why I thought I ever needed anything better. The familiar effortless flow with its fast, sharply defined transients soon took me away. But I managed a few notes. Included among them are phrases such as . . . cello and woodwinds have excellent body and resonance . . . the timbre of the cello is particularly pleasant . . . clarinet has wonderful hollow, reedy sound . . . very lifelike . . . very musical sound . . . exceptionally well controlled bass . . . great brushes . . . sound is extremely open and dynamics have an unlimited feel . . . not the least hint of congestion.
Next, the v6 was substituted for the META. The immediate impression was one of familiarity--not surprising given the amount of time I've spent with the v2. The sound was good but seemed somehow less well defined than with the META. Nevertheless, I continued listening to the same selections and soon the memory of the prior amp faded and the v6 sounded very good indeed. Then I began a series of direct short passage comparisons. My notes include . . . transients seem slightly rounded . . . slower . . . slew rate overrated? . . . cello and woodwinds have less body . . . less air . . . deep bass but slightly mushy . . . sounds somewhat congested in comparison.
I then switched ICs, but none of the three tried made a quantifiable difference.
Next up was the iPod paired with the META and the HD600. The sound seemed very similar to that of the EJ1000 with this combination. I tried several quick switches with difficult passages and my opinion didn't change--they sound practically identical.
Then I switched to the v6 with the same iPod--HD600 combination. There was a subtle but definite drop in quality. I made several META/v6 switches to be sure, but in the end felt confident that the v6 is outclassed by the META.
Next I tried the iPod with the HD600s and no amp. The immediate difference was the obvious: lower available volume. But although lower, the output was considerably beyond my preferred listening level if not beyond my tolerance. My notes from this portion of the test include . . . sounds better than v6 . . . wider, faster, sharper, cleaner transients . . . better definition and inner detail . . . best with no amp at all! . . . excellent dynamics . . . much, much better than anticipated . . . bass slightly boomy compared to META? . . . Sinatra's voice with just the right amount of raspiness.
A few additional notes on the iPod. When using an external amp, I've always set the amp's volume to full on and adjusted the system volume with the iPod. This test indicated rather conclusively that this is wrong. Although running counter to conventional wisdom, the best combined output results from setting the iPod's output to maximum and adjusting the volume from the amp. I presume this is due to the iPod's digital circuitry since it apparently has no effect whatever on the players dynamic headroom. Run in this way, I encountered no clipping whatsoever. The reason I chose to use the iPod's headphone output rather than its line-out was that in comparing it directly against the EJ1000s line-out I could detect no difference. I'll reserve the line-out test for another segment.
Regarding the ICs, heres a rundown on those I used:
The Straightwire IC is a 12-incher with low profile right angle connectors. It's well constructed and sufficiently flexible for portable use.
The Kimber is a 12-inch cable with right angle Switchcraft connectors. This cable, though obviously of very high quality, isn't suitable for many portable applications. The large connectors, combined with the stiff Kimber PJB cabling is simply too cumbersome for my taste. I used it for a while in a Headroom Airbag with the EJ1000 before finally switching to a more flexible choice. I now use the Straightwire and Xin cables interchangeably.
The Xin OFC is a 9-inch cable with right angle connectors. It's extremely flexible, but is a dog cosmetically due to the shrink-tube covering of the connectors. Personally, I don't find this objectionable, but I do prefer the low profile Straightwire connectors for their exceptional compactness.
As we all know, the requirements and considerations for ICs differ somewhat between home and portable systems. There is an audible difference between those I chose, but it's subtle and not sufficient to overcome the convenience of a more flexible cable in this application.
Now, by way of summary, a little Socratean self interview:
Q. Have there been any surprises so far?
A. Yes. There is a greater difference than expected between the META and the SuperMini. Also, I was surprised by the iPod's ability to drive the HD600s.
Q. Has the test changed the way you'll use your gear?
A. Yes. In many cases I will no longer use an amp with the iPod. Since my preferred method of listening is increasingly centered on the iPod, this is a significant change.
Q. Don't you feel the META contributes to the iPod's performance?
A. Not really. I believe the reason the META sounds good with the iPod is that it doesn't obviously alter the iPod's already excellent headphone output. In my view, it contributes nothing other than added volume. Conventional wisdom notwithstanding, it actually is possible for an amp to improve upon the original source owing to the different load it presents to the preamp. The real test will come when I compare the META and iPod's line-out with the headphone output. I expect great things from the META in this case.
Q. Is the crossfeed option on the v6 a worthwhile investment?
A. This is a Catch-22 for those upgrading from earlier versions of the SM. Xin offers a whopping $60 discount, but only if they include the $39 crossfeed. This is the reason I ordered it. But since I can hear no difference whether it's on or off, if the v6 were my first SuperMini I wouldn't order it. I should mention that I'm not really a crossfeed fan, however. Also, my META includes a "blend" feature that does essentially the same thing and I can't hear that either. In fact, I can only occasionally hear a difference with the Corda's crossfeed and that is supposedly the best of the lot.
Q. Since you rate the META above the SuperMini, do you plan to get rid of your v6?
A. No way. It's an excellent performer and still the most convenient amp out there. Keep in mind that the SuperMini suffers only in direct comparison to the META. I've used a v2 for many months and have always been delighted with it.
Q. So what happened to the comparisons of the other headphones?
A. I'm not yet finished with those and I've run out of time. I thought it best to post this rather than wait for the whole kaboodle. Besides, it's too damned long already. I've got to run for the airport.
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META42 Specs:
- Serpac H-65-9V case, measuring 2.75" x 4.94" x .94" high
- AD8620 dual op amp soldered directly onto board for
shortest possible signal path
- Cascode FET current sources to operate the op amp in
Class A mode
- 3 EL2001 output buffers per channel.
- EL2001 buffer in internal power supply with TLE2426
railspliter
- Power supply caps: four 470uF electrolytics, as well
as two 6.8uF Wima poly caps
- 3 Amp Crowbar diode to protect against a reversed
battery
- DC-coupled circuitry
- Vishay/Dale 1% Metal Film resistors
- Teflon insulated silver plated OFC wire for input/output paths
- Sockets for the output buffer ICs and gain resistors
- Switchable Blend function with internal pot for
tweaking value. [Similar to crossfeed]
- Output resistors replaced with socketed jumpers
- Gain is 9.6
- Case has external compartment for a standard size 9
volt battery. The battery used was a fully charged Plainview 9.6v
NiMH.
- Total standby current of approximately 13-14 mA giving
about 30 hours on an alkaline battery or 13 hours on
a rechargeable NMiH battery.
External Power Supply:
- 500mA supply with external voltage
regulator/filter box operating at 18 volts
- LM317 1.5A voltage regulator for 0.01%/V line
regulation, short circuit protection and 80dB ripple
rejection
- Additional 3000uF capacitance for filtering
