Sennheiser HD650 vs AKG Q701 QJ

[EUVL]

I said 701 + DAO, didn't I ?

Thin bass ? Never !!!!!



BTW JH, try adding a 65R-0.1µ Zobel in parallel to the 701 coil.
See if you like it more.
The 65R you can make up from 2x 2W 130R metal film.
0.1µ should be a good MKP, or even FKP if you can get them.


Patrick

[qusp]

ha I just realised how I automatically insert HD600 when someone asks about HD650, they arent as different as people claim, but I definitely prefer the 600. people who say the hd600 are light on bass are off their rocker.

[jameshillj]

Ah Patrick,

Yes, tried the filter loading, but not those values - will try this one, and thanks - the Xfeed does tailor the perceived response a bit as well, and the re wiring also helps also.

Looking forward to your new headamp design next year, with all the bells & whistles!

Jeremy, all this headphone modding is right up your alley!

[Ouroboros]

I have the poor man's version of the 600, the HD580. These (and the HD600) do need a good dedicated headphone amp to give their best performance.

[otherside]

Thanks for your views, i expected nothing less.

Yes indeed i think i need to try them first. Not easy to find them in the very few high end stores in Edinburgh but i'll give it shot.

Cheers

[EUVL]

If you don't have a powerful enough amp the K701 will not sound as it should.
It also needs 50~100 hours run-in.
Beware of that.


Patrick

[qusp]

are we talking more than 5WP/ch?

[Blues]

Audio Features/Specifications

Frequency Response: 10Hz - 39.8kHz
Maximum Input Power: 200 mW
Input Impedance: 62 ohms
Sensitivity: 105 dB SPL/V

I don't see the sense of driving these cans with headamps having more than 200mW unless we want a couple of curly fried voice coils.

That max input power will already generate about 116dB SPLs which we also don't want directly into our ear drums. 200mW also requires just 3.52V of input voltage at the 62-ohm impedance.

Tyll Hertsens' data here (lower right corner) http://www.innerfidelity.com/images/AKGK701.pdf are more like it for normal listening. 2mW! is aplenty...I don't think we even need headamps.

[EUVL]

Perhaps a few questions :

1. Does a moving coil still behaves like an inductor or resistor when the coil us under motion and induces back emf as a result of its velocity ?
2. Is this back emf constant with time, or in phase with the signal ?
3. Why would someone want to have a low output impedance, as well as fast current reserves, in e.g. his 100W Class A Pass Power Amp ?
4. What is your normal listening power level when using one of these power amps to drive your loud speakers ?
5. What would be the typical output impedance of an opamp (if you want to use them to drive phones) ?
6. If you have a headphone amp which can output say 200mW, what do you think the distortion would be at full power (200mW) ?
7. What would be the distortion of the same amplifier at say 10mW ?

Of course there are people who like to drive loudspeakers with 4W Class A tube amps.
No problem with that, everyone to his own taste.


Merry Christmas,
Patrick

[EUVL]

Oh, almost forgotten.

The DAO follower is capable of 10Vrms output, and max Class A current of >200mA while still well within its linear region.
Bandwidth is way over 1MHz even with a source impedance of 2.4k.


Patrick