headphone amp

builder22 · 30 Jun 2017 at 13:57

I spend so much time listening on headphones I've finally treated myself to some AKG 701 and Sennheiser HD600, intention was to only keep one but as I say I spend so much time with audio they'll be worth it...

I haven't read enough to understand why but the AKG's are always quieter for the same volume setting compared to the Sennheisers... despite being MUCH lower impedance

I bought a Fiio E10k with them...it's ok but I kinda misunderstood its function...I thought it could be a DAC OR Amp, never realised the only audio input is from the inbuilt DAC, I have an interface/dac for the PC

so looking for an amp...under £200 I think but not set in stone

is there an amp that would be good for both sets of 'phones?

am i going to get a massive increase in volume/quality for under £200 compared to the Fiio E10k?

EsaT · 30 Jun 2017 at 15:28

builder22 said:
I haven't read enough to understand why but the AKG's are always quieter for the same volume setting compared to the Sennheisers... despite being MUCH lower impedance

That's because impedance tells only how much headphones draw current per voltage, but nothing about what's their efficiency in producing sound pressure from electric power.
And AKGs tend to be at best mediocre in efficiency needing good amount of power to be loud.

In fact very low impedance and bad efficiency is technically the worst possible combination.
Because that means power is taken as current instead of voltage and it's current which stresses headphone driving output.
And low headphone impedance needs low output impedance to avoid decrease of damping factor.
Besides that there are other factors making current fashion of low impedances technically very counterproductive for best sound.

And there are means to drive those headphones well for half of that budget.
Like Objective2 designed to be pathologically neutral and "one size fits all" capable to driving about any possible headphones...
Loud enough to fast cause major hearing loss, if you're not careful.

But if you do any gaming (or watch movies) you would want binaural-simulation for best experience.
Especially those AKG 701s should be extremely/"god mode" good for picking direction and distance cues of various sounds:

(all settings to stereo and no effects/processing for that to work)

So before continuing better look into uses.

Rroff · 30 Jun 2017 at 15:36

Those headphones I believe have very different requirements to drive them - if you stick with the HD650s I'd recommend getting an amp that has atleast 12 volt rails (24v rail to rail) which should ensure the output vrms is high enough to have full control of the drivers - despite on paper only needing something like 2.2 or 2.5 vrms or something they really don't sound great until you push it upto like double that or a little more IMO.

Glanza · 30 Jun 2017 at 16:20

Schiit Magni 2 well within your budget.

rids57 · 30 Jun 2017 at 16:23

^
Schiit Magni 2 - I use mine to drive both my HD650s and AKG K702s (with bass mod) and it does a fine job with both.

builder22 · 30 Jun 2017 at 18:09

sorry, HD600, not 650... (edited)

have seen the schiit mentioned quite a lot...the tube amps too. From what I can gather a solid state will be nore neutral/clerer, or a tube would be warmer/softer, maybe less detailed?

Rroff and Esat...I need to read up on voltage/current etc but that will help what to look for, thanks

The AKG's do sound much more spacious but I'll never use them for gaming, mainly music late at night. I see people mention their soundstage a lot...the distance the drivers are away from the ears and the size of the pads must have something to do with that! They're very clear...wondering if they'll get better with another amp other than thsi fiio

TALON1973 · 30 Jun 2017 at 20:40

if you bought the 600 new , send them back and order the 650.

Rroff · 30 Jun 2017 at 20:44

TALON1973 said:
if you bought the 600 new , send them back and order the 650.

Depends what his requirement and taste in music is - personally I use the 600s over the 650s except with specific types of music.

builder22 · 30 Jun 2017 at 21:38

truth be told.. I had both 600 and 650....sending the 650's back. Thought there was more punch to the 600's even tho the 650's have more bass. Can 'feel' the 600s more at the same volume...if that makes sense. Most of what I listen to is fairly energetic/sharp so the 600s made more sense.
Tempted to keep all three but I'll spend more time changing and comparing than playing!

EsaT · 30 Jun 2017 at 21:50

builder22 said:
have seen the schiit mentioned quite a lot...the tube amps too. From what I can gather a solid state will be nore neutral/clerer, or a tube would be warmer/softer, maybe less detailed?

The AKG's do sound much more spacious but I'll never use them for gaming, mainly music late at night. I see people mention their soundstage a lot...the distance the drivers are away from the ears and the size of the pads must have something to do with that! They're very clear...wondering if they'll get better with another amp other than thsi fiio

Semiconductors and especially proper audio opamps are lot more precise than tubes can ever be and capable to more neutral/transparent sound.
At higher power levels discrete transistors win ICs, but at lower power levels (like headphones) ICs win:
Because they can contain custom components, with all of them situated in same silicon die hence being easy to match to work together and have similar temperature behavior.
Whole "tube sound" is really just distortion of signal from its original.
(now wasn't there supposed to be word "fidelity" in Hifi...)

Yeah, AKG 701s should have soundstage more like concert hall of symphony orchestra.
Which with fitting frequency response (including very neutral bass) makes them apparently one of the absolutely best headphones for competitive gaming.

While HD600/650 Sennheisers are apparently more toward "private room" soundstage.
That would be minus for gaming regardless of frequency response, but can certainly work better in music.
Heck, Turttle Beach Z60 has very "agressive first row" feel in certain type music...
But that BF4 comparison feels like putting head into bucket because of completely lacking sound stage.

If you want to read about electric engineering part here's some
http://nwavguy.blogspot.fi/2011/02/headphone-impedance-explained.html
http://nwavguy.blogspot.fi/2011/02/headphone-amp-impedance.html
http://nwavguy.blogspot.fi/2011/09/more-power.html

AKG K701s are mentioned in site but Hifimans are the most power and current hungry headphones, with 600 ohm Beyers most voltage hungry ones. (1-4)
http://nwavguy.blogspot.fi/2011/07/o2-design-process.html
Sure don't want to try how loud O2 could drive 250 ohm Beyers...

builder22 said:
Tempted to keep all three but I'll spend more time changing and comparing than playing!

Don't you know audiophiles listen only sound of cables and distortion of amplifiers or at most some sine wave test signals?

TALON1973 · 30 Jun 2017 at 21:56

Rroff said:
Depends what his requirement and taste in music is - personally I use the 600s over the 650s except with specific types of music.

The 598 sound better than than 600. i own all 3

builder22 · 30 Jun 2017 at 22:09

what do you not like about 600/prefer on the 650?

partly due to the price but the AKG's were a no brainer, using them for transcribing (slowing down songs to 30% and still be able to pick out individual notes without it just becoming a blurry mess) and playing they're amazing
the HD600 and 650 not so sure about but prefer the 600, although not convinced there's something else that would suit me better...

builder22 · 30 Jun 2017 at 22:12

EsaT said:
Semiconductors and especially proper audio opamps are lot more precise than tubes can ever be and capable to more neutral/transparent sound.
At higher power levels discrete transistors win ICs, but at lower power levels (like headphones) ICs win:
Because they can contain custom components, with all of them situated in same silicon die hence being easy to match to work together and have similar temperature behavior.
Whole "tube sound" is really just distortion of signal from its original.
(now wasn't there supposed to be word "fidelity" in Hifi...)

Yeah, AKG 701s should have soundstage more like concert hall of symphony orchestra.
Which with fitting frequency response (including very neutral bass) makes them apparently one of the absolutely best headphones for competitive gaming.

While HD600/650 Sennheisers are apparently more toward "private room" soundstage.
That would be minus for gaming regardless of frequency response, but can certainly work better in music.
Heck, Turttle Beach Z60 has very "agressive first row" feel in certain type music...
But that BF4 comparison feels like putting head into bucket because of completely lacking sound stage.

If you want to read about electric engineering part here's some
http://nwavguy.blogspot.fi/2011/02/headphone-impedance-explained.html
http://nwavguy.blogspot.fi/2011/02/headphone-amp-impedance.html
http://nwavguy.blogspot.fi/2011/09/more-power.html

AKG K701s are mentioned in site but Hifimans are the most power and current hungry headphones, with 600 ohm Beyers most voltage hungry ones. (1-4)
http://nwavguy.blogspot.fi/2011/07/o2-design-process.html
Sure don't want to try how loud O2 could drive 250 ohm Beyers...

Don't you know audiophiles listen only sound of cables and distortion of amplifiers or at most some sine wave test signals?

thanks, I'll have a read of that!

maybe a bit unfair comparing the headphones without a decent amp but I'm guessing the differences will be much the same regardless..

I have a Kemper guitar amp that has a stereo input.it kinda works as a headphone amp
the headphone out 'nominal impedance' is 33ohms, is that high/low or irrelevant?

Rroff · 30 Jun 2017 at 23:00

TALON1973 said:
The 598 sound better than than 600. i own all 3

Not if you amp them properly and appreciate reference grade audio. The 598 are great for entertainment use but are designed for a different market to the 600s.

rids57 · 1 Jul 2017 at 02:41

a 33ohm output impedance will affect the Sennheisers quite badly, it will cause the bass to become quite bloated and woolly.
It will affect the AKGs differently due to their vastly different frequency v impedance graph and will cause the high frequencies to blur slightly.
The Schiit Magni 2 by comparison has an output impedance of 0.1 or 0.2 ohms.

Rroff · 1 Jul 2017 at 02:51

EsaT said:
But that BF4 comparison feels like putting head into bucket because of completely lacking sound stage.

I really don't rate my 600s with BF4 or for that matter any competitive gaming - definitely need headphones that have a wider and more artificial sense of separation and a driver that sounds more responsive. For music though especially if you have a decent quality/lossless source of some well mastered music the 600s are just another level with the right amp.

EsaT · 1 Jul 2017 at 12:34

builder22 said:
maybe a bit unfair comparing the headphones without a decent amp but I'm guessing the differences will be much the same regardless..

the headphone out 'nominal impedance' is 33ohms, is that high/low or irrelevant?

That output impedance isn't any problem for 200+ ohm headphones.
Like 300 ohm HD600/650 or 250/600 ohm Beyers.
It's these fashionable low impedance headphones which are problem.
Ratio of 8 between headphone impedance and output impedance is considered enough to be at very good level.

But 60 ohm HD598/599 have decreased damping factor, along with their frequency dependant impedance causing bass bloat.
Because impedance of output and headphones forms frequency dependant voltage divider with bigger part of outputted power driving headphone at its impedance spike frequency.
Though there are plenty of headphones with flat impedance curve, like 32 ohm Beyers, which wouldn't suffer frequency response changes.
No doubt also other factors in headphones affect how they respond to lowering damping factor.
After initial bass bloat HD595 completely loses impact/power of bass at some point, when I tested with serial resistor based volume control.

Inadequate output can have two basic results: Inadequate volume or clipping of signal.

If amplification is low with signal staying inside limits of output then it just simply limits available volume.
That's basically the situation if you try to use high impedance headphones with portable player or some all in one device.
DAC's output and amplification are matched to output's voltage limit with 100% volume setting being full unclipped signal level.

If amplification exceeds output's limit that causes clipping of waveform because running out of voltage.
That can happen easily when amplifier is separate device from source of analog signal possibly trying to amplify lot already high level input signal.
Also if headphones are inefficient needing lots of power and have lowish impedance (like many Hifimans) they can simply draw so much current that it exceeds outputs abilities again causing clipping of signal.
(or in worst case too high current draw burns output)

Rroff · 1 Jul 2017 at 15:06

^^ good post. I suspect this is partly why Sennheiser have gone down the route of low impedance, high sensitivity (generally more than most other brands) for a lot of their mainstream consumer headphones.

builder22 · 1 Jul 2017 at 17:26

gonna take a bit more reading to fully grasp how impedance/current/volts/damping work together

....would it be fair to say that with a decent amp the AKG's will remain the same but more volume, maybe better top end?
but the HD600 will sound different due to the varying impedance at different frequencies? ie my fiio amp and other sources might be struggling at some frequencies just now?

http://graphs.headphone.com/graphCo...D[]=573&graphID[]=703&graphID[]=4313&scale=30

http://graphs.headphone.com/index.php?graphID[0]=573&graphID[1]=703&graphID[2]=4313&graphID[3]=&scale=30&graphType=7&buttonSelection=Update+Graph

a Schhit Magni 2 seems to be the obvious route

EsaT · 1 Jul 2017 at 23:00

builder22 said:
gonna take a bit more reading to fully grasp how impedance/current/volts/damping work together

....would it be fair to say that with a decent amp the AKG's will remain the same but more volume, maybe better top end?
but the HD600 will sound different due to the varying impedance at different frequencies? ie my fiio amp and other sources might be struggling at some frequencies just now?

HD600's 300 ohm impedance makes 33 ohm output impedance almost meaningless for frequency response.
Difference in part of total output power driving headphones is that of between 90% and 93% so only ~3% increase.
Even some 50 ohm output difference wouldn't make much difference to frequense response.

But for 60 ohm HD598's with 280 ohm impedance spike at driver's resonant frequency that would be difference between 65% and 90% which is 38% increase.
Though those headphones are bass neutral at default so boost of some dBs won't make bass overpowering...

Frequency response of human hearing depends on sound pressure with sensitivity to bass and treble compared to mids dropping with decrease of sound pressure.
Once so called "loudness compensation" was actually common feature to counter that.
https://en.wikipedia.org/wiki/Loudness_compensation
That's likely behind lots of sensed sound quality drop of AKG 701 with inadequate output:
Already neutral to start with bass becomes even more powerless feeling and also treble becomes muffled.