Author Topic: High Impedance Headphones [150/750 Ohms] And HP Amps  (Read 696 times)

Offline AlleyCat

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High Impedance Headphones [150/750 Ohms] And HP Amps
« on: October 19, 2017, 03:45:38 PM »
Anybody have any suggestions on which portable amps to use with high impedance  [150/750 Ohms] headphones with active circuits, such as the Sennheiser PXC 450's [ noise cancelling ]?

Thank you.
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Offline EduanB

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #1 on: October 19, 2017, 04:00:46 PM »
At first, I was confused with what you meant by 150/750 Ohms. Turns out the impedance changes when you enable ANC.

Seeing as the PXC450 has a fairly high sensitivity of 108 dB SPL/mW, you can reach about 110dB with a dragonfly black (1.2V) with the ANC on (750 Ohm).
See this useful calculator: http://www.digizoid.com/headphones-power.html

Offline AlleyCat

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #2 on: October 19, 2017, 04:33:38 PM »
Thanks EduanB, and for the useful calculator. Any other suggestions?
"Not everything meaningful is measurable, and not everything measurable is meaningful" - Floyd Toole

Offline EduanB

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #3 on: October 19, 2017, 09:29:09 PM »
As I see it there are 2 types of portable amps.

With a battery.
Pros:
  - Doesn't drain your phone's battery as much
  - More power
  - Some could be used as a battery bank
Cons:
  - Another battery to remember to charge
  - Larger + heavier
  - If the battery eventually dies you probably have to throw it away (unless you find a replacement)

Without a battery
Pros:
  - Light and very portable
  - No battery that can die
Cons:
  - Less power
  - Drains your phone faster (though not that much)

Some suggestions:
Most of the FiiO stuff gets good reviews, especially for the money
Audioquest Dragonfly Black/Red
Meridian Explorer 2
Oppo HA2
Chord Mojo
Woo Audio WA8 Eclipse (money no object)

Before spending too much on a portable amp consider whether it would have been better to get a nice dedicated DAP or spend the money on better headphones.

Offline Hi-Phibian

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #4 on: October 19, 2017, 10:46:38 PM »

Some suggestions:
Most of the FiiO stuff gets good reviews, especially for the money
Audioquest Dragonfly Black/Red
Meridian Explorer 2
Oppo HA2
Chord Mojo
Woo Audio WA8 Eclipse (money no object)


Curious as to you experience with above.  How would you rate the Meridian vs the DF red?

Anyhow.  Consider the Soundblaster E5. 
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Offline AlleyCat

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #5 on: October 20, 2017, 09:26:35 PM »
Thanks guys for the suggestions, keep 'em coming please.

I have an ADL X1 [Headphone Amp / USB DAC / iDevice DAC] which has the following spec [part thereof] :

Max Headphone Output Levels (1%THD 1KHz) :
34mW(12 ohm), 60mW(16 ohm), 82mW(32 ohm), 86mW(56 ohm),
36mW(300 ohm), 19mW(600 ohm)
Channel separation: 60 ~ 64dB (1KHz)33ohm , -50dB/<=3dB
Frequency characteristics: 20Hz ~ 20kHz (0.5dB)
Total Harmonic Distortion: : 0.033% (33ohm) , <0.02% (300ohm) ,
0.0085% (600ohm)/1mW
S/N Ratio: 95.5dB/32ohm , 98.1dB/56ohm , 101.6dB/300ohm , 102.1dB/600ohm

I have the volume nearly maxed out and can appreciate the lack of power and control this amp has on the headphones. I like the sound a lot and it comes very close to the 600/650's.

I upgraded from one of the earlier Fiio models, listened to the earlier Audioquest Dragonfly's - didn't appeal and settled on the ADL X1. I primarily listen to this unit on my ipod [ all music AIFF] through my Sennheiser Momentum Over Ears, but this PXC 450 offers so much more.

I would like to realise the full potential of these dated 'phones with a portable amp with sufficient power to drive them.

[Would love to listen to the Chord Mojo, and to own any of the Woo products, the Meridian is way too expensive and over-priced].

Keep 'em coming, thank you.
"Not everything meaningful is measurable, and not everything measurable is meaningful" - Floyd Toole

Offline capetownwatches

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #6 on: October 21, 2017, 07:18:27 PM »
The Cayin C5 is an excellent performer IMHO, and available here for very reasonable money:

https://www.amazon.com/Cayin-Portable-Audio-Headphone-Amplifier/dp/B00OAPDHDI/ref=sr_1_1?ie=UTF8&qid=1508605925&sr=8-1&keywords=cayin+c5&refinements=p_n_shipping_option-bin%3A3242350011

Rated output power: 800mW + 800mW (32 ohm load)
SNR: ≥101dB (A-weighted)

I have used one with my LG V20 and it has gain to spare - should drive your headphones properly.
It is also very well put together.

Amps: NFB11.32 [upgraded] - Little Dot MKll [upgraded] - X-Can V3
DAC:   Benchmark DAC1 USB
Cans:  LCD2F - HD600 - DT990Pro 250 - K612Pro - K171MKll - Y50

Offline AlleyCat

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #7 on: October 22, 2017, 09:19:36 PM »
Thanks capetownwatches. Interesting.

Here's a video comparing it to the Fiio E12 [ skip to about the halfway and watch from there to get a fair idea of the quality of sound. The first half is largely about differences/complaints about peripheral things such as cables and rubber bands].

It seems a a really decent performer, especially in terms of the bass quality and power.

Do you still have yours and did you import it?

Thanks again.

https://www.youtube.com/watch?v=ojzU7gEnbU0
"Not everything meaningful is measurable, and not everything measurable is meaningful" - Floyd Toole

Offline naughty

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #8 on: October 22, 2017, 09:27:27 PM »
If I was going to try any portable headphone dac/amp now as an alternative my Nuprime uDSD I would only consider self importing an ifi iDSD micro (black label)

Offline AlleyCat

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #9 on: October 22, 2017, 10:02:07 PM »
^^ Nice, very nice specs, not so nice price [ imagine the closest looking Donald Trump comedian would saying that, the one where Mike Pence is mostly with him].
"Not everything meaningful is measurable, and not everything measurable is meaningful" - Floyd Toole

Offline capetownwatches

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Re: High Impedance Headphones [150/750 Ohms] And HP Amps
« Reply #10 on: October 23, 2017, 10:45:18 AM »
Thanks capetownwatches. Interesting.

Here's a video comparing it to the Fiio E12 [ skip to about the halfway and watch from there to get a fair idea of the quality of sound. The first half is largely about differences/complaints about peripheral things such as cables and rubber bands].

It seems a a really decent performer, especially in terms of the bass quality and power.

Do you still have yours and did you import it?

Thanks again.

https://www.youtube.com/watch?v=ojzU7gEnbU0

It is a more than decent performer - seems to have the edge on the E12 (now replaced by A5) in terms of sound quality.
I got mine through Amazon and used my MYUS account - took about 10 days and very smooth.

Recommended - www.myus.com

I sold mine to a friend since I found myself never using it for portable use - my V20 is more than capable without additional amping.
Only when listening to the odd file that has VERY high dynamic range do I feel it could use a bit more grunt, and I tend not to listen to those on the go anyway.



Amps: NFB11.32 [upgraded] - Little Dot MKll [upgraded] - X-Can V3
DAC:   Benchmark DAC1 USB
Cans:  LCD2F - HD600 - DT990Pro 250 - K612Pro - K171MKll - Y50