Oppo PM-3 : The Portable Planar - Impressions

[leng jai]

Anyone know if the PM-3s are more efficient than the PM-2? The latter is supposed to be pretty good straight out of a phone.

 

[MattTCG]

   
HA-2...c'est la vie!!!!

 
I knew somebody would say that. 

 And yes I agree. 

 

[miceblue]

The bass slam is subdued compared to the pm-3 on a desktop amp. 

How so? I don't hear much bass difference between my MacBook's headphone output and the Objective 2.

 

[Max Choiral]

  The pm-3 scales up appreciably with a decent desktop amp. So far I'm pretty disappointed with the pm-3/fiio x5 combo.

X5 can't drive low impedance headphones to adequate level. 
This is the most common mistake because most people think that such headphones don't need amp.

 

[redogfizbal]

Man that's to bad, I'm getting heavy bass slam direct out of my iPhone!

 

[MattTCG]

Oh well. I can use the ifi micro to pair with the x5 and it will drive the pm-3 with determined authority. I was just hoping to be good with the x5. That's what I get for not doing my homework properly. 

 

[miceblue]

X5 can't drive low impedance headphones to adequate level. 
This is the most common mistake because most people think that such headphones don't need amp.

How so? The X5 outputs 255 mW at 32 ohms. That's plenty for the PM-3 at 102 dB/mW.

 

[Max Choiral]

How so? The X5 outputs 255 mW at 32 ohms. That's plenty for the PM-3 at 102 dB/mW.

Man, it's not about numbers, it's about the quality of amp section. Try at least smth like Centance Hifi-M8 & more likely you will hear the difference in the bass section (structure, speed, tightness)
Low impedance headphones demand good amperage, most daps lack it. Even desktop amps

 

[MattTCG]

Okay, I hooked up the micro to the x5 and it rocks the pm3...hard. So this will work for me. If I start traveling more I'll probably buy the h2.

Thanks guys.

 

[redogfizbal]

H2 looks very enticing. I just wonder if it's worth the hassle. I've always been about simple is better.

 

[chailee80]

H2 looks very enticing. I just wonder if it's worth the hassle. I've always been about simple is better.

Quite honestly i have a hard time noticing much difference between the ha-2 and my ipad, most of my music is only itunes 256k aac or 320k mp3 so i tend to just plug directly into my portable devices to keep things simple. The pm-3 seems very well tuned for smartphones, ipods etc...The ha-2 is mainly used with the desktop and laptop.

 

[miceblue]

X5 can't drive low impedance headphones to adequate level.
This is the most common mistake because most people think that such headphones don't need amp.

How so? The X5 outputs 255 mW at 32 ohms. That's plenty for the PM-3 at 102 dB/mW.

Man, it's not about numbers, it's about the quality of amp section. Try at least smth like Centance Hifi-M8 & more likely you will hear the difference in the bass section (structure, speed, tightness)
Low impedance headphones demand good amperage, most daps lack it. Even desktop amps

If an amp has a provided number at a low impedance, it has enough current at that load.

Quality != drive, and you specifically said drive.

A headphone is properly driven if it has enough voltage and current. The X5 offers plenty of current as dictated by the power output levels at 16 and 32 ohms and should drive the PM-3, and other low-impedance loads just fine.

Spoiler: Physics and Math

Ohm's Law:
P = I * V
P = I^2 * R
P = V^2 / R

X5's specifications
460 mW at a 16 ohm load, <1% THD+N
0.460/sqrt(0.460*16) = 169.55 mA, 2.71 Vrms

255 mW at a 32 ohm load, <1% THD+N
0.255/sqrt(0.255*32) = 89.26 mA, 2.85 Vrms

28 mW at a 300 ohm load, <1% THD+N
0.028/sqrt(0.028*300) = 9.66 mA, 2.89 Vrms


PM-3's specifications:
1 mW to reach 102 dB SPL at a 26 ohm load
0.001/sqrt(0.001*26) = 6.230 mA, 0.16 Vrms needed from the amplifier

2^6 or 64 times the power is needed from the amplifier to reach 120 dB SPL
120 dB SPL - 102 dB SPL = 18 dB SPL
double the power from the amplifier for every +3 dB SPL gain
18 dB SPL / 3 dB SPL = 6, or the amplifier needs to double its power 6 times to let the PM-3 reach 120 dB SPL

64 mW needed for the PM-3 to reach 120 dB SPL
0.064/sqrt(0.064*26) = 49.6 mA, 1.28 Vrms needed from the amplifier, the X5 can provide way more than those requirements and can thus sufficiently drive the PM-3


I'd say the X5 is voltage-limited for high-impedance headphones, and indeed it is with 8 Vp-p maximum (FiiO's specifications). You can see that the voltage outputs at 32 and 300 ohms are its limiting factor, and current most certainly doesn't seem to be.

Of course quality matters though, I don't think anyone will deny that.

 

[money4me247]

  Anyone know if the PM-3s are more efficient than the PM-2? The latter is supposed to be pretty good straight out of a phone.

yes, easier to drive. technically capable of playing directly from any source without amplification. whether you feel like or how much extra gear you want to add would be personal choice, depending on what kind a subtle improvements you are looking for. (imo).

 

[MickeyVee]

Anyone know if the PM3 mates well with the AK100 II?  I'm planning on getting the PM3 as soon as it becomes locally available.  This will probably become my around the house and travel rig.  Seems to make more sense than the HE400i and from what I've been reading, I think I'll really enjoy them. Canada / US exchange rate is crazy right now and as soon as my local Oppo dealer gets them, I'm in! 

 

 

[Mcberto]

Just got my pair in for a couple of hours now. I would have to agree with Matt that having additional power to drive the PM-3's definitely brings it into a different level.
 
I guess I'll see if I'll be travelling a lot to justify buying a HA-2 to pair with the PM-3's.
 
So far so good in my opinion.