Harman/Kardon Receiver


Sometime ago I acquired for $75.00 a Harman/Kardon 430 receiver in exellent condition (all original) for a small bedroom system. After having it serviced, I have recently begun to use it, and I am astonished at how musical it sounds.  Associated equipment include Snell J IV speakers and a Cary 308-T cd player, interconnects are by The Cord Company and speaker cable is by NAIM.  The sound is so musical and satisfying that I can listen to it all day without any listener fatigue at all.  My question is if some of you experts on receivers could tell me why it sounds so good? I have no information at all about this receiver and would appreciate any insights the Audiogon family could provide.
For what it is worth, in the past I heard a Harman/Kardon 730 receiver and did not find it nearly as involving musically.
Thanks to all in advance and cheers.
Avondale
fuenteclara
The list of champions competing with today's high-end monsters:

Pioneer SX980, SX1280,
Sansui AU 717, H.H.Scott Stereomaster 

to name just few out of many...

i have a 430.   it sounds good because they knew how to make a good receiver back then.   and more power from the 730 proves more power dosent mean better sound.  last i saw, the 430's were going for $200 and up on the bay.  
The HK 430 is a bit of an anomaly.  Not all receivers of that vintage sound so good.  Prevalent use of discrete componentry, oversized power supply for the design and engineers who actually listened to the product probably explains most of it.  

I owned one, garage sale purchase for $20, took it home and gave it the classic Deoxit treatment.  Ran it with a Nak CD player and a pair if Snell K monitors.  Also ran Rogers LS3/5As, Spica TC 50s and various other monitors with satisfaction.  A ridiculous product for the investment.