[HiWire]

Uh oh... time for a new source and amp. A Head-Fier and his/her money are easily parted

 

[taymat]

Dam so both these headphones will need a really good amp? Well that doubles the purchase price then.

I'm not sure I'll be getting them now unless they're really, really good.

 

[trbl]

Quote:

Originally Posted by Jan Meier Dear Headfellows, these phones are very insensitive and need a high signal voltage. They, for instance need considerably more signal than the HD600 and HD650. Jan

Huh. My specsheet for the HD600 says they're rated at 97 dB/mW. That works out to (for a 300 ohm impedance) about 102 dB/V. And the specsheet for the K701 rates it at 105 dB/V, or about 3 dB higher sensitivity than the HD600.

Is the published K701 spec wrong?

 

[rsaavedra]

Quote:

Originally Posted by Jan Meier However, I would like to give a warning to all those who intend to buy these new AKG phones. Despite their impedance of just 120 Ohm these phones are very insensitive and need a high signal voltage.

Quote:

Originally Posted by trbl And the specsheet for the K701 rates it at 105 dB/V, or about 3 dB higher sensitivity than the HD600. Is the published K701 spec wrong?

Notice Dr. Meier mentioned impedance == 120 Ohms, that means he was talking about the K601. The K701 has impedance == 60 Ohms, here links to their specs:
AKG K601 specifications
AKG K701 specifications

If I understand this correctly, it seems the K601 will be harder to drive than the K701?

 

[chris719]

Lower impedances are harder to drive, if the sensitivity remains the same.

Much of the confusion stems from the fact that the HD6x0 is high impedance but very sensitive to the amp used, but this does not mean it is hard to drive..

 

[trbl]

Quote:

Originally Posted by rsaavedra If I understand this correctly, it seems the K601 will be harder to drive than the K701?

It depends if the specifications from AKG are correct. The K601 is rated at 101 dB/V, compared to the stated 105 dB/V for the K701. That would make the K601 about 1 dB less sensitive than the HD600 and 4 dB less sensitive than the K701.

Of course for an amplifier with a high output impedance the apparent sensitivity of the AKG's with respect to the 300 ohm Sennheisers will be further reduced.

I trust things will get clearer as more people have a chance to try and report on the new AKG's.

 

[morbo667]

Quote:

Originally Posted by Jan Meier ... You need a source of decent output voltage (2 Volts) and an headamp with adequate gain factor (x5 is barely enough) otherwise you will be very disappointed!

does this really mean that a Corda HA2 Mk2 SE would be too weak to drive those cans???

 

[Cronstead]

I don't get it ... if the new cans are very good, then posting the impressions about them is going to give it free advertisement ....
Unless, they are exteremely bad performers .... which I hope not as I have very high expectation from them.

 

[philodox]

To add to the confusion, I remember reading something about how AKG measures their headphones differently than everyone else... so maybe those numbers arent all that acurate in direct comparison to stuff from Sennheiser and the like?

 

[Jap]

Quote:

Originally Posted by taymat Dam so both these headphones will need a really good amp? Well that doubles the purchase price then. I'm not sure I'll be getting them now unless they're really, really good.

[size=small]
This isn't surprising at all---all of the top-tier phones need a robust amplifier to sound their best. Even with low impedance phones like Grados, you can drive, say, an RS-1 with a low-powered amp, but one needs an amp with plenty of oomph! to serve these cans properly. All of the top tiered AKG phones---the K1000, K340, K501, even the closed K271---require amps with gusto. If the K601 and K701 are truly the reference cans for any manufacturer, especially AKG!, they need to be shoveled lots of power.

[/size]

 

[Voodoochile]

[size=xx-small]I think it would be easier to just have Todd do my taxes this year.[/size]

 

[ReDVsion]

Quote:

Originally Posted by Jap [size=small] [...]even the closed K271---require amps with gusto.[/size]

Debatable... I ran the K271 out of my AP192 for a while and thought it sounded just fine.

 

[marvin]

There are two limiting factors (power wise at least) to amplifiers, voltage swing and current drive.

Grado SR-225 (97dB/mW) and Senn HD-580 (98dB/mW) have pretty similar sensetivity ratings, but really different impedances (32 ohm/300 ohm). To get to the same SPL, the Grado will need 3 times more current than the Senns, while the Senns will need 3 times more voltage.

That's pretty much why some amps will sound good with the Grados (A47 and RA-1, both of which can supply lots of current), but not as good with the HD-580 because the HD-580 don't benefit as much from current buffers and those amps don't supply the required voltage swing to get the HD-580s volume up.

If the sensitivity specs are comparable, the K601's are right in that range, and with an impedance of 120 ohms, should split the difference between the Senns and Grados in terms of voltage and current requirements.

But from what Jan Meier is saying, the sensitivity of the K601's is a lot lower than that of the Grado's and Senn's, and will hard to drive with lots of voltage swing and current drive needed.

 

[Jan Meier]

Dear Headfellows,

> Notice Dr. Meier mentioned impedance == 120 Ohms, that means he was talking about the K601. The K701 has impedance == 60 Ohms

> If I understand this correctly, it seems the K601 will be harder to drive than the K701?

It's true, the K701 has 60 Ohms and is slightly more easy to drive. Sorry for the misunderstanding.

It even is true that the K701 is slightly more sensitive than the HD650. However, since the K701 has less bass-impact than the HD650 the latter produces more "WOW-effect" at lower sound levels. the slightly recessed bass of the K701 easily seduces people wanting to turn up volume more.

Cheers

Jan

 

[rsaavedra]

Quote:

Originally Posted by Jan Meier However, since the K701 has less bass-impact than the HD650 the latter produces more "WOW-effect" at lower sound levels.

So where would you place the magnitude of the bass of the 701 between the 501 and the 650? Maybe closer to the 501, or closer to the 650? In the middle?

Also if possible, are their mids and highs comparable (or possibly even better) than the K501's?