Sony A845 RMAA Tests
Jul 4, 2010 at 10:31 PM Post #2 of 16

yuriv

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There's an unusual result. Not that it'll make an audible difference when hooking it up to line in, but the headphone output with no load has better numbers than line out.
 
One question: how many dB did the output drop when you hooked up the V-modas? Say, at the RMAA level-adjustment screen? If we assume that the load is 16-ohms (and mostly resistive) at 1kHz, we may be able to come up with a ballpark figure for the headphone output's source impedance, at least at 1k. It can't be that low given the frequency response while driving the SE530.
 
Jul 5, 2010 at 1:44 AM Post #3 of 16

james444

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Thanks, this echoes my thoughts when I got the line-out cable. However, can we be certain that it's not the cable's fault?
 
Jul 5, 2010 at 4:29 AM Post #4 of 16

dfkt

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James444, I don't think the cable is faulty. When plugged in it automatically disables the volume control, even in the GUI display, and it delivers sound - so it should be in perfect working condition, I assume.
 
Yuriv, unloaded headphone-out gave -8.8dB into my sound card, with the 16 Ohm load it gave -18.9dB. (My multimeter says the resistance of the V-Modas is exactly 16 Ohm, while the resistance of the SE530's crossover seems to be 25 Ohm.)
 
The result with the SE530 reminded me somewhat of the Hifiman... good thing people don't make that big drama about the Sony player. :wink:
 
I did a volume-matched listening test with a few tracks between the Sony A845, the Sansa Clip+, and the headphone-out of my AudioFire4. While there were absolutely no audible differences with the Panasonic HJE900 (26 Ohm dynamic driver), Koss KSC75 (65 Ohm dynamic driver), HFI780 (36 Ohm dynamic driver) - there was a somewhat noticeable difference with my UE11 (18 Ohm impedance, 8 Ohm resistance, multi-armature) out of the Sony, compared to the other two sources: it sounded thinner, brighter. Not as extreme as the frequency response in the RMAA test suggests, but still somewhat off from the ideal.
 
Jul 5, 2010 at 5:22 AM Post #5 of 16

elfary

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It seems that you're a really skilled headfier dfkt. Do you know what is theapproximate crosstalk value you could measure through a 22 Ohms iem and a t3 amp and an iPhone 3GS as source ?
 
I
 
Jul 5, 2010 at 11:07 AM Post #7 of 16

dfkt

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The A845 headphone-out is average, pretty much the same as any other brand player on the market. The line-out measures worse than the headphone-out, but I can't say if it is audible. James444 and Shigzeo say the line-out sounds noticeably worse than the headphone-out. I didn't listen to the line-out. In any case, the treble roll-off of the A845 line-out is much less severe than the Hifiman's.
 
I only did listening tests with the headphone-out, which confirmed that the A845 sounds no different than any other player with average IEMs or phones. It however struggles to drive complicated multi-armature crossovers properly.
 
On a side note, the cheap Sony B153 stick measured quite a bit better than the A845, but that's only on paper - it still sounded the same as any other player. B153 RMAA test is here: http://rmaa.elektrokrishna.com/Comparisons/Hifiman%20vs%20AMP3%20Pro%201%20vs%20Sony%20B143%20vs%20Clip%2B.htm
 
---
 
Elfary, I have neither an iPhone nor a T3 nor a 22 Ohm phone. Sorry, can't help you there. If I had these things, I would have measured them already.
 
Jul 5, 2010 at 11:35 AM Post #8 of 16

Ypoknons

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Always good to see a dose of objectivity in the portables field. 
 
At least the LOD gets rid of the one volume control, which is nice. But if it degrades audio quality, then it wouldn't be worth it. :/ I guess better to live with two volume controls and have the money for 3 more bowls of premium Wonton noodles. 
 
I wonder how my PCM-M10 would deal with multi-BA IEMs. It clears the no-load tests pretty good, though D50 is the real star. 
 
Jul 6, 2010 at 1:34 AM Post #9 of 16

yuriv

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Quote:
dfkt said:

... Yuriv, unloaded headphone-out gave -8.8dB into my sound card, with the 16 Ohm load it gave -18.9dB. (My multimeter says the resistance of the V-Modas is exactly 16 Ohm, while the resistance of the SE530's crossover seems to be 25 Ohm.)
...

 
Wow, the output drops -10.1 dB when introducing a 16-ohm load. That means the voltage drops down to roughly 31% of its original level. Assuming that the V-modas are 16-ohms resistive at 1kHz, the A845's computed output impedance is ~35 ohms. That's almost twice that of the HM801, which is to say that it is nowhere close to being an ideal voltage source. Someone double-check my math, but if you compare your A845 and HM801 measurements, you'll see that the A845's frequency response has greater ups and downs while driving the SE530.
 
Even with modest gear like single-driver BA IEMs, you should be able to hear the difference between the A845 and something much closer to a stiff voltage source like a Sansa Clip/Clip+/Fuze or a late-model iPod, by listening for FR differences alone.
 
Jul 6, 2010 at 3:58 AM Post #10 of 16

shigzeo

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I haven't published my A828 LOD and HPO RMAA scores yet, but I wasn't too impressed by the A845 LO and the HPO, which sounded good, has discernible artefacts such as clicks and pops in the back ground with sensitive earphones.
 
A845 RMAA LOD and unloaded test. I did not publish loaded tests.
 
DFKT is right: I wasn't impressed by the A845 and actually, sold it!
 
Jul 6, 2010 at 6:11 AM Post #11 of 16

elfary

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Thanks anyway DFKT (And Shigzeo as well). It's great to have a database of RMAA tests to have some hard data that can enlighten our ears.
 
I'm about to purchase an iBasso T3 to replace my first ever amp (E5) and thanks to these tests (Amongst other things) i know what to expect (Aside for the obvious overall SQ leap forward).
 
Jul 6, 2010 at 8:47 PM Post #12 of 16

shigzeo

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Try to remember that an amp is just an amp. I CAN fix the deficiencies (if any) in your source, but it may not. If you tend to use dynamic earphones with your player and your player has no frequency deficiencies with low impedance earphones, you will be down to the more subjective differences of stereo separation and distortion, two areas that are frequently argued upon.
 
Some people love channel bleed even if it isn't in the original signal: and it makes sense with headphone listening since headphones sever the continuity there. Secondly, distortion, which can sound warm, fuzzy, and nice, may be lowered. The T3 is a high performance (bug decently priced) headphone amp. It WILL drive any iem on the market to impossible volumes, and with little distortion, good channel separation and perfect frequency response. That means music CAN sound more like the original signal.
 
Remember that we are talking to audiophiles here who tend to want to eschew the original signal; oftentimes, what sounds like the original sounds 'digital'. So in some ways, a high performance amp will actually (though sounding truer to the recording), introduce a thread of discomfort. I tend to like everything a good amp can do, but that doesn't mean that in all areas, the amp is 'better'. 
 
Still, the T3 is one of the best for iems, particularly for balanced armatures and particularly if you have a player with an output that gets sweaty when running lowΩ earphones.
 
Jul 7, 2010 at 5:47 AM Post #13 of 16

dfkt

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This is very much off-topic for this thread, but here goes:
 
I haven't heard the T3, but the T4 really isn't worth the money at all. Somewhat shabby build quality (dirty PCB with some unprofessional solder joints), cheap yet blingy materials used, hiss with IEMs (despite the "made for IEMs" slogan on the amp), etc, etc... now the T3 might have fixed some of those issues, but IMO it's still a somewhat iffy company that's behind that amp. iBasso lost my trust, but of course YMMV.
 
For an alternative I would recommend taking a good long look at the Headstage Arrow 12HE. That's the only amp I ever tried that does pretty much everything right.
 
Ok, back to the A845 RMAA...
 
Jul 7, 2010 at 5:56 AM Post #14 of 16

shigzeo

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I on the other hand, haven't tried the T4. The T3 isn't a structural brick house, but it is made on par for its price. As an amp (and that only) with a good hardware layout, it is great. I've had only good dealings with iBasso and currently own 3 of their amps (T3, T3D, and P3+) though admittedly, I don't use them very often. The T3 has much less hiss than any of my Sony's - about as much as a Cowon D2, maybe less. It isn't annoying. Every amp I have ever heard hisses to some degree from its output, so I am not put off by this. However, amps that really really hiss are unusuable for IEM's. 
 
The A845 was always strapped to the T3D as I could not stand the player's hiss.
 
Jul 8, 2010 at 4:41 PM Post #15 of 16

elfary

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I have not yet ordered the T3.I made up my mind for the T3 vs the Arrow because of the size and the waiting list that tArrow has these days.

My main listening is on Shure se420's which are 22ohms and dual balanced armature drivers. I don't know yet how this specs affect to my sources (iPhone 3gs and 09 iPod Classic). What i do feel is that amping the classic via lod with a fiio e5 warms up the sound at the expense of high end clarity and soundstage so i was hoping to get rid of these side effects with the T3
 

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