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The Sub-$200 Portable Amps Shootout – 13 (+11) amps compared - Page 4

post #46 of 451
Quote:
Originally Posted by ClieOS View Post

If I were using full size most of the time, I am probably not going to bother with output impedance that much. But given I am pretty dedicated IEM user and how popular IEM has became, I just thought that will be an useful information for consideration... Anyway, where can I get a sponsorship from Amazon? biggrin.gif
I'm sure if you copy/pasted your IEM reviews into Amazon and asked for us Head-Fi'ers to vote your review as helpful, that would at least get you into the Vine program... But I bet there is a better, more direct way. You could just say you have reviewed a library of IEMs on head-Fi, here is a link to my threads and all the people who thanked me for my info & added to my total thread views, and Amazon should consider adding you as an asset to their portable audio sales efforts.

About my amp consideration, I do use my Etymotic IEMs, and I figured if an amp supplies enough current for a low Ohm headphone it should do well for a 62 Ohm full size. I might've just stuck with my E5 to be honest, except my E5 has it's bass boost stuck on, the amp has to almost max it's power output to get to a normal listening volume, and of course new stuff is cool.
post #47 of 451
Quote:
Originally Posted by ClieOS View Post

EMI from iPod? I don't realize iPod is capable of radio wave emission (of significant level) at all. Are you sure it isn't the noise from some other components? For example, microdrive from older iPod, etc. I could understand if it is an iPhone cause those are known to be real bad with EMI (I am using a Samsung for testing, btw). Also, what headphone you were using at the time? I tested with SE530, which is notorious for picking up hiss. But I am certain there are worst out there. Even so, wait till you hear the FSM-01 before you know what counts as really bad hissing - it is like having two mosquitos flying inside your ears.
My C421 are all current models btw.


They are.

I had signicant EMI using the Alpen with a 4G Ipod touch. Loved the amp/DAC, but that was the main reason I sold it. If using WiFi with the Alpen I would get a low level intermittent buzz/squeal.

post #48 of 451
Thread Starter 
Quote:
Originally Posted by RingingEars View Post


They are.
I had signicant EMI using the Alpen with a 4G Ipod touch. Loved the amp/DAC, but that was the main reason I sold it. If using WiFi with the Alpen I would get a low level intermittent buzz/squeal.

Obviously if that's the case, Apple will have to answer for the problem. Since I am not much of an Apple user, I can't test for them. However, I am still not convince it is EMI in the iPod case but rather a case of blackground noise. Wifi is another matter of its own. It runs in a much higher band (GHz) than cellphone (MHz) but often in very intense manner in short distance in order to carry large amount of data. This means anything in close distance will get interference even with shielding. The amp is literally being bombarded by microwave.
Edited by ClieOS - 8/17/12 at 7:38pm
post #49 of 451
Quote:
Originally Posted by ClieOS View Post


 Obviously if that's the case, Apple will have to answer for the problem.

 

ClieOS.

I'm not sure how it's Apples fault... Or Fiio's really. I think it's just the nature of the beast.

I never get/got the interference when running the Ipod alone and I listen to Pandora more than my own files. With the amp hooked up to the ipod I got interference when WiFi was on, but never got it when it was off. So the ipod must have some sort of shielding and I assume that is by design being that WiFi is part of the attraction to the device.

Now like I said I don't think it's Fiio's fault either and I imagine that there would be some level of interference with any amp, amp/DAC unless this was specifically addressed in the engineering of the device, which, these manufactures should look into since streaming is here to stay and only getting more popular.

post #50 of 451
Thread Starter 
No, I am not talking about Wifi, but rather the possible EMI issue from your average, no-wifi iPod. While I am far from owning a big number of DAP, none from my collection has EMI issue that I am aware of. Why would a consumer grade DAP emits that much EMI is quite beyond me.
post #51 of 451
Quote:
Originally Posted by ClieOS View Post

No, I am not talking about Wifi, but rather the possible EMI issue from your average, no-wifi iPod. While I am far from owning a big number of DAP, none from my collection has EMI issue that I am aware of. Why would a consumer grade DAP emits that much EMI is quite beyond me.

You're right I don't think it would(DAPs emitting EMI)So this case would be more an RF problem than EMI(I was using EMI out of context and should have stated RF)

But on the WiFi issue it had to be, in my particular case, a receiving issue as opposed to a transmitting issue because my Fubar 2 MKII sits literally 6" away from my WiFi router and when I had the Fiio hooked up to my computer, at the same distance, running DAC duty I had no issues with it so it had to be the Fiio/Ipod just not playing nice when WiFi was enabled. It would be nice to see portable amp amp/DAC manufactures address this issue if at all possible...

post #52 of 451

I noted that you included models from the sub $100 comparison. What method did you use to rank them  if they weren't tested at the same time? As RMAA is quite sensitive to slightly different testing conditions, causing potentially erroneous results.


Edited by elmura - 8/20/12 at 8:00am
post #53 of 451
Thread Starter 
Quote:
Originally Posted by elmura View Post

I noted that you included models from the sub $100 comparison. What method did you use to rank them  if they weren't tested at the same time? As RMAA is quite sensitive to slightly different testing conditions, causing potentially erroneous results.

I didn't mention it but I did remeasure a few of the sub-$100 amp in order to compare result - but that is not the point, as RMAA is only used to (1) establish the baseline for comparison. As some measurement (i.e. FR curve) never varies much between measurements, while critical flaws (said any significant anomaly like high level of noise) can be easily spotted. Also, (2) RMAA result doesn't directly affect most of the criteria and how they are rated. This review isn't intended to be an summery of measurement. It is still as much about subjective opinion as it is objective measurement.

I do understand RMAA is prone to error, noise and variation in measurement tools, which is the reason why the review was 2 months overdue and at least 5 different RMAA tests were made on all the amps to reach some consistent in result that I can conformable use for comparison. The idea is to see the 'trend', but not the individual result. It is not perfect, but I really can't afford any haif-decent oscilloscope or AP audio analyzer in this life time.
post #54 of 451

Care to post battery life figures for the amps?

post #55 of 451
Thread Starter 
Quote:
Originally Posted by AstralStorm View Post

Care to post battery life figures for the amps?

I will add the official number though I don't think that will be much helpful. Precise measurement will take forever to complete so I am not going to do it, especially since some of the amp (PA2V2, HeadRoom, etc) can run for days on end. But the good news is as far as I can tell, all the official number are pretty close to real battery life.
post #56 of 451
So, basically, most will last for a few listening sessions, enough that you'll lose track of how much battery is left and have to charge them up at some point anyway? Oh well. On a similar note, I like the recent trend of companies to report their battery life conservatively (except smartphones).
post #57 of 451

This thread makes the O2 very attractive to me. :p

 

What I really wonder is how would Fred_fred_2004's 3-channel rechargeble cMoy would fair in the sub-$200 shootout. He sells the rechargeable one for a $100-110 which is the same as the OP reviewed in the sub-$100 except it's rechargeable and comes in a flask-looking metallic case.

 

 

I would love to hear the OP's opinion. Thanks!


Edited by BullHorn - 8/23/12 at 7:11am
post #58 of 451

I can respond to that. They're identical except for the inclusion of a rechargeable battery, power supply, power socket, and a better case. No sound quality difference. The OP already highlighted that he ranked the Fred-Fred 3channel unit equal 5th in the under $200 category. Refer to rankings on pg1

post #59 of 451
Thread Starter 
Yep, judging from the picture of internal circuit, the rechargeable and non-rechargeable version's amp section should be the same.
post #60 of 451

I have to say, the O2 amp + odac combo is pretty awesome. I use it with my JH16s and it really has brought some sonic awesomeness to my music. The thing about the O2 amp is that its dead silent, and without any gain resistors I can actually play around with the volume knob! I had the e17 for a bit, but there was something about it that I didn't like... It felt like the bass leaked into the mid range. Either way, my DIY O2 amp is sticking around for a long time! :)

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