Compare older Sony ES receiver vs. newer gear?

This question relates to my previous post. I own a Sony ES receiver model STR-GA7 ES. It's a Pro-Logic model with 5.1 analog inputs and is rated at 90 WPC (.05%THD)RMS X 3 up front and 40 WPC x 2 rear. It is from model year 1997 (or '98?). My question is regarding the amplifier section. According to Sony, the front three channels have what is called a "parallel push-pull" design with four output transistors per channel. It is rated to drive 4-ohm speakers up front. Can anyone comment on the quality of this type of amp design relative to newer receivers or separates? The overall build quality seems very solid on this receiver - as good if not better compared to some of the newer "flagship" receivers on the market now. Less processing power, of course, but still excellent feel to the buttons/switches, huge heat sinks, etc.

I know that the Sony ES separates amps of the mid-90's were described in Sony sales literature as having the "parallel push-pull" as a major feature and that their ES receivers were supposed to compete performance-wise with separates of that era in theory. Is this just marketing hype? You don't see this amp design mentioned on any of the newer Sony ES Dolby Digital/DTS receivers. Was the amp design dropped due to high cost or because something better has come along? How does this amp compare to MOSFET? My receiver runs very cool, does that mean it is biased very low and switches to class A/B sooner than other 90W amps? I'm using fairly power-hungry speakers (Hales Revelation 2, 6ohm 86db sealed floorstanding three-way) but they still sound very good on this receiver in my 15' x 13" living room.

Just curious if any Sony fans would care to comment.

While I know nothing about Sony's receivers of any genre, I can comment on their last set of ES integrated amps and power amps. They are full MOSFET amps that run class A up to about 15wpc and then switch over into class A/B. I recently replaced my TA-F808ES integrated (100wpc @ 8 ohms) with the TA-N90ES power amp with the same ratings. Only difference I am aware of is the at the power amp is balanced while the integrated is not. Both run every bit as hot at idle or under light load as they do under heavy playing conditions. If your receiver does not run fairly warm then it is obviously not the same design. And I can't believe that it is, in any event. The integrated amp weighs 54 pounds and the power amp weighs 48. Very large x-former and caps as well as heat sinks, etc. Both are quite substantial beasts. And they sound great!! Like a BAT VK-200 for 1/4 the price.
Gpdavis1 - Thanks for your response. I checked the owner's manual and the receiver weighs nearly 31 lbs. Fairly hefty, I think, for a receiver of a 90W X 3 power rating. It will get warm during a movie, but not nearly as hot as some Pioneer Elite receivers I've seen in dealers' showrooms and I know they were MOSFET designs.

Anyway, I've had the "upgrade bug" for awhile now but am honestly having trouble really justifying buying a new power amp or pre/pro + amp. I just don't have room in the rack without getting rid of the turntable. Besides, without conducting a direct "A/B" comparison in my home it's nearly impossible to know what I may be "missing".

All I can say is the sound I'm getting now is very musical to my ears. In other words, I can spend time listening to some very nice gear in local showrooms and still come home, kick up the ES, and get grins. I think careful setup/calibration of my system has paid big dividends in this regard.