[buke9]

thanks for the input but im leaning towards full tube designs now after reading alot of things instead of the hybrid designs

You just missed out a guy was selling a Crack kit for $200 a couple of weeks ago. The Crack is fantastic with the 600's or 650's. It would not be good at all with the HD 598's. With different tubes got my HD 700's to sound pretty good also but it likes high impedance headphones 300 or above. Got a new tube coming in that is going to lower the output impedance even more.

 

[sureshot1234]

  Suit yourself. OTL designs are typically optimized for high-impedance like your HD600, not for lower impedance headphones like the HD598. If you want a great amp under $200 that will work well with all your headphones, I stand by my recommendation.
 
If you're looking seriously at OTL designs, the Schiit Audio Valhalla 2 deserves your consideration. It has a gain switch for use with your lower-impedance headphones. Owned one of those for a while and liked it well enough.

i will look at the valhalla 2 compared to the others im looking at 

 

[buke9]

i will look at the valhalla 2 compared to the others im looking at 

I had a Vahalla 2 for just a bit and it was almost solid state in the sound didn't have it long enough to tube roll but that will be needed IMHO. It is a very powerful and with stock tubes fairly bright. The HD 700's is what I based this on and they are quite bright but this didn't tame them down as a Crack did. Just my opinion .