[basisfunction]

Hello Head-fi,
 
I am a super-lurker who is considering improvements to my home audio equipment. What I have now:
 
Sources:
Technics 1200MKII
Kenwood KD-2055
Apple iPod Touch playing ALAC
 
Receiver:
Harman-Kardon HK-430
 
Headphones:
HD590
HD595
HD598
 
Loudspeakers: HPM-100
 
Standard issue connectors.
 
No headphone amplifier yet.
 
I listen to a spectrum of music from classical to rock, I could be listening to something recorded by Deutsche Grammophon all the way to Steely Dan or Boston.
 
QUESTION: I am considering buying a Little Dot MKIII LD MKIV or MKIVse. Is this overreaching for my level of headphone? Also take into consideration that I am considering getting HD650s in the future.
 
NEXT QUESTION: I like the sound of my HD595 and HD598 as it is, is there a most obvious can I should seek out that is not a Sennheiser product?

 

[Impulsive]

I will just point out fact that your headpohones are low impedance ones, while you choosed amps that have better synergy with high impedance headphones.
I would advise some solid state amp as they are known to have better synergy with low impedance headphones.
 
High-Z headphones needs more voltage to be driven properly and that is what are tube amps good at.
However, Low-Z headphones needs more current and little voltage, and SS amps are good at providing current.