[nutcracker]

Hi folks,
as all of us knows Mr. Srajan Ebaen of 6moons has been reviewing headphone amps over the years, and we also know he uses his AT w1000 woodie and senn650 for comparison. One comment he repeatedly mentions on each fine/semi-fine headphone amps (raptor, sr-71, aural audition vhp-1) is that they do wonderous magic to the senn650 and practically does nothing to the AT woodie. the reason i believe he says is that senn650 is high impedance, and AT is low impedance. While AT woodie already sound as good as it is when hooked on regular phone jack, senn650 sonically becomes better and better with juicier amps. Is this a generally accepted idea that low imp cans improve far less when amped?? (as compared to high imp can like senn650)

 

[philodox]

Pretty much.

 

[braillediver]

His statements are factual based on the resources he has available for reviewing.


Mitch

 

[adhoc]

um - while it is generally known that, compared to a weenie amp, a powerful amp can really push the volts (and to a lesser degree, the mA) into a high-Z phone, it is not generally known that a low-Z phone can bring many a high-end amp to its knees with its power (pure mA, and conversely mW) requirements.

In other words, while having a powerful amp results in a obvious improvement voltage-wise (more volume and an obviously fuller sound), the (more subtle) distortion that comes with a current-starved low-z phone is definitely more difficult to hear.

naturally, if the low-Z phone is also efficient to boot, the distortion becomes even more subtle.

to summarise:

1. it is not too easy to supply enough voltage with current to a high-Z phone. at the same time, it is certainly not difficult to do so if the amp designer gave his design any serious thought.

2. it is uber easy to supply enough voltage to a low-Z phone, but extremely difficult (esp for tubed amps) to supply enough current.

imo, if you want to know for sure whether your amp can handle your low-Z phone, listen carefully to peak transients. the sudden spike in current draw during such instances usually pushes most amps into clipping.

 

[Jahn]

Yep, like that K340 needs a beefy amp to make it even work serviceably, so you will hear a huuuuge improvement from a cmoy to a M3, while a MS-2 sounds very nice out of even dinky looking solid state amps that feed it enough current.

 

[ken36]

Extremely informative. Thanks.

 

[Loftprojection]

Is it really "thumbs down for low imp cans" though?

In a sense, shouldn't a low imp. and very efficient can be the goal of all manufacturers? Well, maybe not $$$ wise if they also produce amps but if their only market is headphones, isn't it a good marketing point to be able to sell a can that does not require a special amp to sound it's best?

I ordered the W1000 some days ago (still waiting for them to arrive!) and the fact that they are easy to drive and supposedly sound at their best even without a dedicated amp was one of the advantages I found in it. I still don't know if they sound good, but if they do and I can get the a similar quality of sound either using my dedicated tube headphone amp or directly out of my minidisk player or portable PC, I will be very happy. My current Beyers definitely don't sound their best without the tube amp.

 

[philodox]

No, not really a thumbs down... just because they don't have as large changes with amplification doesnt make them better or worse in any way, just different.

I've yet to find a headphone that the Dynahi does not drive perfectly. The only problem is that the gain is so high on mine that you dont have much volume range with very low impedence headphones like the Grados.

 

[bigshot]

Quote:

Originally Posted by braillediver His statements are factual based on the resources he has available for reviewing.

You mean like this one?

http://www.6moons.com/industryfeatures/chip/chip.html

I first found six moons mentioned on a classical music newsgroup.
They were making fun of how gullible people can be.

See ya
Steve

 

[mulveling]

The AT L3000 sounds very different when changing amps, probably even moreso than the hd650. The L3000 is around 40 ohms impedance, which is low. I wouldn't have spent the $$$$ to get another amp like Purk's SDS if I didn't strongly believe it was far superior to other amps I've used with the L3000.

The L3000 is extremely resolving, I think that has more influence on the amount of benefit realized from an amp, rather than impedance (to a point).

 

[Kurt]

AFAIK, the AT W1000 is not in the same league as the HD650. This could be another reason.
He might just doesn’t have the same potential to “grow”.

 

[adhoc]

Quote:

Originally Posted by bigshot You mean like this one? http://www.6moons.com/industryfeatures/chip/chip.html I first found six moons mentioned on a classical music newsgroup. They were making fun of how gullible people can be. See ya Steve

reviews like that are the ones giving us audiophiles a bad name...

 

[nutcracker]

Quote:

Originally Posted by adhoc to summarise: 1. it is not too easy to supply enough voltage with current to a high-Z phone. at the same time, it is certainly not difficult to do so if the amp designer gave his design any serious thought. 2. it is uber easy to supply enough voltage to a low-Z phone, but extremely difficult (esp for tubed amps) to supply enough current. imo, if you want to know for sure whether your amp can handle your low-Z phone, listen carefully to peak transients. the sudden spike in current draw during such instances usually pushes most amps into clipping.

so....low-Z cans performs best with amps which will feed sufficient currents into them?? Pardon me for mixing up with the neighboring amp forum, but could anyone tell me the names of those amps, or possible recomendations?
(I asked the same question in the amp forum, but no one came up with a name of such amp......) Thanks

 

[adhoc]

Quote:

Originally Posted by nutcracker so....low-Z cans performs best with amps which will feed sufficient currents into them?? Pardon me for mixing up with the neighboring amp forum, but could anyone tell me the names of those amps, or possible recomendations? (I asked the same question in the amp forum, but no one came up with a name of such amp......) Thanks

FOR LOW-Z PHONES:

tube amps: look for a transformer-coupled output. this lowers the output impedance (ie step-down) of the amp while simultaneously increasing current output. optimal power transfer to low-Z phones is also achieved with the lowered output impedance (tubes typically have output impedances in the thousands of ohms). hence OTL (Output Transformer-Less) designs usually do not do well with low-Z phones. to a lesser degree, you may want to look around for tube amps with 'negative feedback' - usually they do slightly better (less distortion) with both low-Z or high-Z phones at the expense of some gain.

- eddie current hd-25
- melos sha-1
- mapletree audio (DIY or premade)
- optimised morgan jones (DIY) [check over at headwize]
- cavalli-lovell variant (DIY) [check over at headwize]

ss amps: any ss amp can have their buffers 'stacked' in order to provide enough juice; capacitors with larger values can easily be substituted in. add to this the fact that ss amps often have ridiculously low output impedance (<5ohms) and that's why i said it's difficult to design a ss amp that does not do well with low-Z phones. even a cmoy-type design can be modified easily to handle low-Z phones (afaik the secret of the Grado RA-1).

- gilmore lite
- dynahi

now there are also mosfet hybrid type amps out there, but my knowledge of them is sketchy at best.. so

 

[recstar24]

adhoc,

maybe you can answer this or help me out, its a question i have always wondered, is it possibile for an OTL design to provide enough current to low z cans and sound good as well? if so, do you know of any? I am interested in hearing one