New member

There are lots of threads that will address your wants.  You need to do some careful and focused research.

Amps can run from a few hundred to several thousand depending on your needs.

You would have to start with giving a price range that is comfortable to you. Also letting us know what the rest of your setup is might help in determining the right amp for you regarding trying to match synergy with your other components. Also knowing the rest of your setup might help us determine wither an improvement can be made by getting possibly a dac/amp rather than just an stand alone amp. The more info you can give the better of a solution can be formed.

<$150

http://www.head-fi.org/forum/thread/199787/k701-amp-suggestions

<$250

http://www.head-fi.org/forum/thread/412546/another-k701-amp-thread

$200-300

http://www.head-fi.org/forum/thread/346719/akg-k701-amp-recommendations

I think around the $300 range would get you a nice amp. It seems like the darkvoice 336 seems to be a popular inexpensive amp for around that price.

A good amp is a start, but you should also be looking at your source and a good DAC is also recommended in addition to an amp.

A used K701, used amp,  and a used DAC can get you somewhere around $600-$700. Add $50 more for a used sennheiser. An alternative to K701 would be the beyerdynamic dt880 (250ohms) for its price.

 

Solid state or tube?

Trane, that really depends on the tube amp. Generally speaking, you want one with an output impedance below the impedance of the headphones you're driving. Solid state does this well (chips have low impedance output), but tubes typically have a higher output impedance, especially OTL amps, like the inexpensive tube amps mentioned here. Output transformers necessary to get low impedance output are expensive, usually $200 or more for a good pair. That's just for the transformers, not the rest of the amp. There are a few OTL exceptions, like the Zana Deux, but that's $2,200 or you can try building your own. The inexpensive tube amp manufacturers make all sorts of claims and rarely tell you the output impedance. They also employ tricks like heavy-handed (and sound deadening, IMHO) negative feedback to get the output impedance down. If you want decent power at a decent price, stick with solid state. If you want a *good* tube amp (both in sound and construction practices), you are going to have to either pay a bit more cash or build it yourself. The cheap tube amps cut too many corners in construction and sound. However, you can get both good construction and sound for a fair price with solid state.

Depends on how much you want to spend total. If you only have $400 go ampless with a good efficient headphone, but at around $600 onwards you should be able to get a good DAC/amp combo and maybe a HD600 or K701. Don't know about the DT48, personally I'd start with something that everyone else has so you get a good frame of reference.

I've gotten surprisingly good sound having the 70x plugged into my Millet Starving Student Hybrid Tube amp. They can be had for under $150 built. If you can DIY, the parts are also inexpensive. Pair it with the uDac ($75) and you're under $250.

Sadly mine is collecting dust but I'll drag the poor girl out to the NJ meet.