Amp for AKG701??

Well keep in mind that you will want to get an amp AND dac. The dac is a digital to analog converter. You want a clean digital signal going to your source to your dac so that it can be turned into an analog signal and then amplified by your amplifier. 

 

If you are looking at the shciit stuff, then I recommend you check out the schiit modi for the dac and the valhalla for the amp. Then just get better tubes for the valhalla and you should be all set. 

My personal preference is for solid state amplifiers. I am not going to mention any specific amplifiers because I never recommend things I haven't had a lot of experience of myself.

 

However I do have a pair of K701s myself. These headphones are extremely transparent and will sound at their best with good quality transparent amplifiers.

 

Avoid, if you can, amplifiers that colour the sound. These have become very popular even though they are really not hi fi imho. The initial impression of coloured sound can be very good but you will soon tire of it and if you replace the coloured amplifier with a neutral amplifier it is a joy to hear your music without the added colour.

 

Remember that neutral transparent amplifiers allow you to hear the colour that is actually in the music!

 

In your post you mention "good extension, power and timing" all three of these are associated with good quality solid state amplifiers.

 

The next thing I'd suggest is that you consider second-hand amplifiers. For the same money as a new amplifier you can get very much better quality. It might be worth you while to look at some online auctions and get an idea of what is available.

I've read the Lyr has a pretty high noise floor. so I'm guessing it's the tube circuit may need tweaking. The hyper detailed phones will be very sensitive to this. You can get neutral tube amps, it's not a design barrier. Power supplies have to be at least twice as big to offset the wasted heat energy but with enough power, you can certainly make the K shine. I've used a Singlepower tube amp on them for years and loved it. The EC ZD was another tube amp that sings well with them. As you mention, tube bloom and extension roll off are impacting the sound but your gain tube selection has a big say in how much is impacted. When I went to a quality, highly detailed and well extended signal tube (2c51) in the high range, the tube amp gave me what meat that can be had out of the 701s with plenty of sparkle. Both the SP & EC amps are over $2k and have plenty of power reserves to handle the K with ease.

But for a budget, a tube amp has to cut corners and it's the power supply that takes the hit. Start messin with quality and sizing of parts in your power supply, you impact portions of the benefits you gain with tubes. In instances where money is the primary influence on selection, SS will give you more performance. The trick is finding an amp that can do the ambient ques right in the budget catagory. A lot of amps can sound good with a top end source but not everybody has one. Still, for the value level amps, SS is the way to go. With that said, there have been a few (Heed Canamp, Bryston, Schiit Mojo, GSX, B22, etc.) really good SS amps that handle all the dynamic cans and the LCD & th more efficient HE orthos (excl. HE6) but your getting back to bigger power supplies.

What is your budget and people can be more forthcoming with products that work well the harder to drive headphones.

FYI: Jason at Schitt told me in an email that the Valhalla was not the best match for the K701.