[Chris_Himself]

Rocking recabled HD580's with a Creative X-fi w/ these exact mods
http://www.head-fi.org/forum/thread/226975/hotrodding-the-x-fi-a-layman-s-guide-no-56k
 
It does just fine and this setup outperformed my iBasso DAC/amp I had back in the day.
 
Honestly I don't think the HD580/6xx are that hard to drive, they just honestly scale with good amplification well as should all headphones. They're rated at 300ohm, and the opamp I'm using from National Semiconductor says it can comfortably power 600ohm loads. The Cirrus Logic DAC in the x-fi series are actually fairly good and they'll handle bit-matched playback which is a dream when you're listening to FLAC!
 
My advice, get somebody to mod an x-fi for you. I've abandoned headphone amps for years since the upgrade!

 

[svenski]

I recently had the same dilema. I upgraded from the HD595 to the HD650 and budget was an issue. The 595s were easy to drive right out of my sound card. I then purchased the E7 alone only to upgrade a week later to the E7/E9. I would recommend to go all the way as the E7/E9 is available for £130. The E9 drives the 650s nicely. The response seems to be alot more punchy with the E9 compared to the E7 with a better mid range and soundstage. It is interesting that at the first few hours after I got the 650s I felt like I could not use them unamplified while now I sometimes do. On my HTC HD2 phone, the HD650 sounds bearable, say when I want to move about in the house. The E7 connected in between makes the sound a bit smoother but also with less top end. In any case, I always appreciate the difference when I have them hooked up to the E7/E9 where they can shine bearing in mind the small budget for this powerful amp.
 
 

 

[jackmccabe]

How about a used emu 0404  or a used e9 and a used zero dac.
Also you should be able to find a pair of hd650';s for less than £250 easily, I would suggest you look on the for sale forums.
Here they are for £222.80 http://www.okobe.co.uk/ws/product/Sennheiser+HD+650+3m+Wired+HIFI+Stereo+Headphones/1000008989?ref=1q4bs

 

[svenski]

Quote:

How about a used emu 0404  or a used e9 and a used zero dac.
Also you should be able to find a pair of hd650';s for less than £250 easily, I would suggest you look on the for sale forums.
Here they are for £222.80 http://www.okobe.co.uk/ws/product/Sennheiser+HD+650+3m+Wired+HIFI+Stereo+Headphones/1000008989?ref=1q4bs

The above link is very attractive and I tried it lots of times before but it was always out of stock. The best I have seen new was £250. I bougth mine from DV247 for a bit extra as they offer a 4 year warranty and have a store in Cambridge where I had a chance to audition them first.
 

 

[blacknile]

I have a pair of Beyerdynamic DT880 600ohm headphones. I think they're about as difficult to drive as your  650. I have an iBasso D2+ boa as well which (at the highest gain setting) seems to be able to drive them just fine You might want to try that.

 

[PXSS]

Whatever you do, don't go for the E7.
Friend of mine did and he regrets his decision. Even my portable CMoy Dual chip LM6171 & LM4562 Amp which I bought from a member here for about 50eur drives them better. I'd choose the NFB-12 over the E7+E9 combo any day.

 

[Optimus Praim]

Quote:

Whatever you do, don't go for the E7.
Friend of mine did and he regrets his decision. Even my portable CMoy Dual chip LM6171 & LM4562 Amp which I bought from a member here for about 50eur drives them better. I'd choose the NFB-12 over the E7+E9 combo any day.

Fred_Fred surely knows how to build a good performing amp....

E7 is a toy compare to his dual chip Cmoy...

 

[Proglover]

OP is based in UK I think
 
Neco (Neco Soundlabs, based in London) also makes fantastic amps. His mosfet is known to have great synergy with Senns HD6X0. I can also agree on that from personal experience, since I have both his fantastic 9v portable and his mosfet
http://cgi.ebay.nl/ws/eBayISAPI.dll?ViewItem&item=140541708987 
 
I'd recommend it wholeheartly, but it doesn't have a DAC, like NFB-12 does have.
 
The Neco mosfet is in a higher league then E9, way more transparent. I had both and compared.