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Oppo PM-1 Planar Magnetic Headphone Impressions Thread - Page 112

post #1666 of 3447

Agreed, they don't leak nearly as much as HD800s

post #1667 of 3447
Quote:
Originally Posted by x RELIC x View Post

Quote (Click to show)

Not sure why, but the PM-1 looks really sexy next all that gear. Nice to see reference next to something other than the HA-1.

Haha, thanks. I always use sexy when I see something that I like, my kids don't get it they just think I'm weird rolleyes.gif

I will most definitely order the HA-1 but I am really getting amazing results from the PB-2. The right OpAmp choice is key with these phones. Best yet is Muses 02 + bypassed buffers from the Bushmaster II.

Listening now and considering the future of the HD800.
post #1668 of 3447
Quote:
Originally Posted by zilch0md View Post
 

I know that balanced cables can prevent the transducers from influencing each other on a shared ground (as with single-ended cables), but in my admittedly layman's understanding of this topic, these cross-channel impedance fluctuations have to do with the way signal voltages vary and are obviously not the same on each channel and have some kind of interaction with the cable's dialectric.  Whatever the physics, I can't honestly say I have ever heard these cross-channel influences on single-ended cables. I don't even know what I would listen for if trying to detect it. :o 
 
Also: The cable lengths between the amp and transducers are too short and the voltages too high (relative to Line Level voltages) to be concerned about rejecting common-mode interference between amp and headphones. On the subject of Line Level voltages between DAC and amp, I am in the camp that says there is no need to run balanced between DAC and amp - not unless you've got a really long cable run, where common-mode interference could be a problem at those lower voltages. 
 
In my opinion, the biggest bang for the buck when going to balanced cables between amp and headphone comes not from the aforementioned cross-channel voltage fluctuations, but when using amplifiers that offer more power at a four-conductor output than at a three-conductor TRS jack - if and only if, the headphone is insensitive enough, relative to the amp's power output, to actually enjoy an improvement in dynamics or bass energy and control, for example.  That is a use of balanced cables that I can testify is both audible and substantial, in some cases.  The more sensitive the headphone, the less difference between single-ended and balanced operation on my iBasso PB2 Pelican portable amp, for example, which most definitely puts out twice the power to its balanced connector as it does to its TRS jack. 
 
Even though I can hear a difference in dynamics and bass control when using the LCD-2 balanced on the iBasso portable amp, vs. with half the power output of its TRS jack, I stil prefer to use balanced cables with every headphone if it's an option even when no power-related benefits can be heard. (Indeed, I have balanced cables for every headphone.)  I do this just on my understanding that the "experts" say balanced is better - even if I can't hear a difference, once volume-matched.  I'm the same way with power supplies - I'll run with battery packs, when that's an option, rather than use a PSU that could introduce line noise - even if I can't hear a difference.  I attempt to minimize every weakness on the assumption that the total experience is a sum of its parts, as long as one link in the chain is not excessively compromised relative to the others.

 

In other words, for the PM-1, I can live without balanced cables (my favorite rig for the PM-1 is single-ended), but if the amp supports it, why not?

 

Mike

 

This is, by far, the most rational and reasoned explanation of the use and benefits of balanced cables that I have seen on this site.  Hats off to you sir.

post #1669 of 3447
Quote:
Originally Posted by Maxx134 View Post

I realize you have an LCD but I have to dissagree about trebles.
The PM1 has to me a "Mosfet" sounding trebles while the LCD X has more clarity/brightness than even rest of the LCD line from my memory.

 

I have listened to the LCD2 and 3 only briefly so I cant really comment on the treble on those phones.

 

I will have to go back and compare the PM1 and the X again though.

post #1670 of 3447

I’m in the middle of some testing for a planned review, thought you guys might want to read my notes so far.

 

By specs, the OPPOs should be amazingly easy to drive.  Here are the numbers from the OPPO site:

 

Nominal Impedance: 32 Ohm

Sensitivity: 102db in 1mW

Long-Term Max Power Input: 500mW

Transient Max Power Input:  2000mW

 

With that crazy low impedance and high sensitivity these cans should get very loud with a minimum of power.  Doing the math you only need about 20 mW to drive the phone to 115 dB. Almost any portable device these days can output that much power.  But I was more interested in sound quality than quantity.  I set up an experiment feeding the phones from three different amps.  As you can see any of these amps should be able to adequately (or massively) power these phones:

 

 

FiiO E11

  • Portable stack amp
  • Battery only
  • Power set to High
  • EQ set to 1

JDS Labs O2

  • Desktop\Portable
  • AC\Battery
  • Gain set to Low

Audio-gd Master 8

  • Full sized amp
  • AC only
  • Gain set to Low
  • Power set to High (because I could!)

 

Frequency Response 20-20

+/- 0.1 dB

+/- 0.1 dB

+/- 0.15 dB

Max Output 33 Ohms

101 mW

613 mW

 

Max Output 50 Ohms

 

 

7000 mW

Output Impedance

0.5 Ohms

0.54 Ohms

1 ohm

 

Amps were chosen on the basis that 1) they represent a wide range of power output at 32 Ohms, and 2) they were available.  Specs were measured in the wild for the FiiO and O2 so they don't match the manufacturer's posted specs.  Audio-gd specs were provided by the manufacture, who didn't deign to provide numbers for lowly 32 Ohm headphones because who would ever plug something that small into the beast?

 

All Amps were fed with the same chain and hardware: PC with J River 19 >  USB2  >  Mytek 192 Stereo DSD DAC  >  Unbalanced Cables > AMP > SE cable to OPPO PM1.

Amps were sound level matched at 82 dB with pink noise before testing.  I used test tracks from the new " Dr. Chesky: The Ultimate Headphone Demonstration Disc" (which I will say lives up to its name.  Absolutely terrific, check out Jude's posting on it here.) 

 

I am still testing this evening but here are findings so far.  My findings may be the results of the amps different sound signature as much as the power levels, so take them as you may.


Testing at high volume:

 

Volume:  The headphone was easily driven by all three amps even on complex \ intense music at high volumes.   I level matched with pink noise at 82 dB so transients in music were easily 100 and above.

Noise:  At the start of testing the JDS Labs O2 clipped noticeably with transients, as I had accidentally left the gain set to "High."  Changing the gain to "Low" solved the problem. Other than that no noticeable distortion on or noise from any of the amps.

Depth of field:  Good on all three amps but clearly better with the audio-gd.  Very acceptable on the FiiO for a battery only amp.

Dynamic range:  This went in order of power:  Worst on FiiO, best on Audio-gd.  Very good on Audio GD.

Attack \ Transient Response:  Acceptable across all amps, better on FiiO E11, best on audio-gd.

Timbre \ Texture: good across all three, very slightly better on Audio-gd.

 

Summary (so far)

 

The PM 1 could be easily driven at insane volume with a watch battery.  At high volumes, performance does increase with more powerful \ better amplification.

Dynamic range increases noticeably, depth of field increases noticeably.  Attack\transient response very good even with low power and benefits only slightly by better amplification.  Timbre\texture is good even at low power.

 

The low impedance of these phones would dictate using an amp with an output impedance of below 4.  Many portable devices such as smartphones don’t publish their output impedance, and some suck, so buyer beware if that’s your planned use. The amps I tested with have excellent output impedances of 1 Ohm or below and I heard no distortion introduced by any of the amps (with the correctable exception of the O2 on high gain).

 

Edited for spelling


Edited by ogodei - 5/4/14 at 4:11pm
post #1671 of 3447

I ordered the Oppo PM-1 Planar Magnetic Headphone on March 30. Should arrive May 7. Talk about anxious! 


Edited by icysparks - 5/4/14 at 5:57pm
post #1672 of 3447
What's the resistance of these. Edit 32 ohms? The Pandora hope is only 8 ohms. Thats sensitive. I would like to hear a comparison of those two
Edited by grizzlybeast - 5/4/14 at 6:12pm
post #1673 of 3447
Quote:
Originally Posted by SpudHarris View Post


Funny you should say that..... I can now use the PM-1 with everything. Nigel's audio playpen (Click to show)




Not sure if I'm brave enough to try the speaker taps on the TP80 biggrin.gif

 

Haha!  I hear you, but "cute" went for a speaker amp - with no apparent problems (thus far).

 

:D

 

Quote:
Originally Posted by SpudHarris View Post

[snip]

I will most definitely order the HA-1 but I am really getting amazing results from the PB-2. The right OpAmp choice is key with these phones. Best yet is Muses 02 + bypassed buffers from the Bushmaster II.

Listening now and considering the future of the HD800.

 

That's funny!  With your massive collection of op-amps for the iBasso PB2 (and my relatively modest collection), we're both running our PB2s with Muses 02 and dummy buffers.

 

:D

 

I run mine that way for the HD800, though, not for the PM-1, but I would say that the Muses 02 does make the PM-1 sound more like the LCD-2 - thicker mids and bass. As previously posted, I prefer the more neutral, brighter, and analytical OPA1611s with dummy buffers for the PM-1 - or better still, the OPA1611-equipped Meier Stepdance on 15VDC battery power.  This gives me absolutely all the sparkle I personally want from the PM-1, with everything else still falling into place nicely.  

 

There's no right or wrong to this, of course - that's the beauty of rolling op-amps - flavor of the week!  

:beerchug:

 

Is the Beresford Bushmaster MkII growing on you (as a DAC)?  

 

I tried some switching back and forth between my Resonessence Concero and the Bushmaster MkII yesterday - about the third time I've revisited using the Concero as a DAC instead of as simply a USB-to-SPDIF converter.  I still prefer the Bushmaster MkII with a neutral amp and the PM-1.  The Concero sounds thin and cold, in comparison - great for the LCD-2, but not as nice as the Bushmaster MkII for more neutral headphones.  I think a lot of Concero fans are using tube amps with HD800's for example - evidence that you've got to have some warmth somewhere along the chain with the Concero (in my opinion.)

 

Mike

post #1674 of 3447
Quote:
Originally Posted by ogodei View Post

 

This is, by far, the most rational and reasoned explanation of the use and benefits of balanced cables that I have seen on this site.  Hats off to you sir.

 

Gee, thank you, ogodei!  

 

I won't be able to wear a hat for the next three days.  (Big head!)

 

:D

post #1675 of 3447
The pm1 was well received at the Atlanta meet today and got a lot of play time. There was a brand new pair there and mine which had about 30+ hours on them. Several people said that mine sounded better. Fwiw
post #1676 of 3447

Big difference after burn in on the PM-1 needs minimum 50 hrs before they start to soudn good. Out of the box I first was not impressed at all.

post #1677 of 3447
Quote:

Originally Posted by ogodel View Post

 

I’m in the middle of some testing for a planned review, thought you guys might want to read my notes so far.

 

By specs, the OPPOs should be amazingly easy to drive.  Here are the numbers from the OPPO site:

 

Nominal Impedance: 32 Ohm

Sensitivity: 102db in 1mW

Long-Term Max Power Input: 500mW

Transient Max Power Input:  2000mW

 

With that crazy low impedance and high sensitivity these cans should get very loud with a minimum of power.  Doing the math you only need about 20 mW to drive the phone to 115 dB. Almost any portable device these days can output that much power.  But I was more interested in sound quality than quantity....

 

...Summary (so far)

 

The PM 1 could be easily driven at insane volume with a watch battery.  At high volumes, performance does increase with more powerful \ better amplification.

Dynamic range increases noticeably, depth of field increases noticeably.  Attack\transient response very good even with low power and benefits only slightly by better amplification.  Timbre\texture is good even at low power.

 

The low impedance of these phones would dictate using an amp with an output impedance of below 4.  Many portable devices such as smartphones don’t publish their output impedance, and some suck, so buyer beware if that’s your planned use. The amps I tested with have excellent output impedances of 1 Ohm or below and I heard no distortion introduced by any of the amps (with the correctable exception of the O2 on high gain).

 

Compared to the FIIO® E11 (Zs = 0.5Ω), I knew that my Asus® STX'™ internal Texas Instruments® TP6120A2 (Zs = 10.7Ω) would be at some disadvantage driving a reactive 32Ω load due to the resultant electrical-damping deficit; data on the PM-1 from both Oppo® and independent testers, however, indicate an almost purely resistive load, so the TP6120A2 may prove good enough.  Given the PM-1's 500mW RMS limit, what external "straight" headphone amplifiers (dual-RCA analog inputs) would be the most appropriate to A/B against the TP6120A2 for low-level fidelity?

post #1678 of 3447
Quote:
Originally Posted by Maxx134 View Post

My experience was only about half as much leak as an hd800
I realize you have an LCD but I have to dissagree about trebles.
The PM1 has to me a "Mosfet" sounding trebles while the LCD X has more clarity/brightness than even rest of the LCD line from my memory.
You have a double wammy of euphonic sound as I feel the PM1 to already have a tube like quality.

you should come clean man - it is an impressions thread after all wink.gif
post #1679 of 3447
Quote:
Originally Posted by Frank I View Post

Big difference after burn in on the PM-1 needs minimum 50 hrs before they start to soudn good.

X2.
post #1680 of 3447
Quote:
Originally Posted by zilch0md View Post
 

 

Haha!  I hear you, but "cute" went for a speaker amp - with no apparent problems (thus far).

 

:D

 

That's funny!  With your massive collection of op-amps for the iBasso PB2 (and my relatively modest collection), we're both running our PB2s with Muses 02 and dummy buffers.

 

:D

 

 

Tried the TP80 speaker amp briefly last night (feeling brave after a couple of San Miguel) and although wonderful sounding, with no music playing the hiss was unbearable so went back to the PB-2....

 

I think the Muses01 are probably going to be where I end up but at the moment I only have 2 of them and they are in the P4 and Fi-Quest, you know me, I will be rolling like a nutter any time soon :p 

 

I have been so impressed by the PM-1, more than I ever expected given the cost. I've lived with mine for over a week now and can't wait for each listening session. Can only imagine what the HA-1 will do for them.

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