Sony 777ES vs Sony 7100 ES Receiver upgrade?

Well, here is my opinion for what it is worth. DON'T BUY ANOTHER SONY RECEIVER TO DRIVE YOUR B&Ws!!!

Most B&W speakers have a low ohm dip at certain frequencies (1.7 ohm for some of the 800 series, I think, not sure about the 700s). This is something that requires very robust amplification to handle - the kind entirely lacking from Sony receivers of which I am aware. I am not a Sony basher - they do some things very well. But Japanese receivers typically have poor power supplies, and your 170Wx7 receiver is not really giving anything like 170 watts into each of all 7 channels at 8 ohms, and once the ohm load drops significantly your receiver is going to sputter big time.

If you want a receiver (of course separates would be better, but much more expensive), I would look at an Arcam Diva AVR 300. This is probably in the same price range and will do an astronomically better job with your speakers. Be sure you do a comparison audition if you can so you can hear for yourself. But in my opinion trying to drive your B&W’s with the Sony is grossly unfair to them and really a waste of money - you will never begin to appreciate what your speakers could and should sound like.

Note: the AVR 300 is listed as 100W x 7channels, as opposed to the 170 rating for the Sony you quote. DON’T BE FOOLED (sorry for shouting again). This is a MUCH more powerful receiver.

If I remember correctly, the 777 has preamp outs. I would buy a good multi-channel power amp and add it to the receiver. They're many good amps that can be had for the cost of a new receiver.
I found the 170w of digital power (STR DA5000es) to not even sound as powerful as the older DA3es receiver.
Also, the fellow above is correct. You need an amp capable of driving 4 ohms with no trouble. Most receivers don't like this low of an impedance.

Sorry Newmanoc, I think you may be mistaken unless you have listened to the Sony 7100ES Receiver.

I have a few asian magazines showing multiple owner setups and reviews using a Sony 9000ES receiver. One magazine reports writes an article where they goe to an owner's house using the 9000ES receiver which powers a pair of B&W Signature 800 + Signature HTM + four 704 for surrounds in a Qualia setup (TV & PJ).

Even at this demo Sony HS-60 Projector demo, the Sony 7100ES powers 3 PMC IB2's and the room is huge! Those PMCs are power hungry just like N802s.
http://www.avbuzz.com/audio-video/200509/sony-sa/show/index.htm

I think these new high-end receivers CAN power some of the bigger monsters. However, you may not get the great quality 2 channel you are desiring.

I am a believer that a receiver cant power much as I use separates myself.

But sometimes you just wonder.

However, some flagship models can deliver especially in this day of the new digital amps.

Jwatusi: Your Sony 777 can do ok with your old 603s but with 703 you will need slightly more power and the 703s are a more detailed speaker.
The main differenece between the 7100 and your 777 besides power are the new surround formats. Whether you want/need them is your choice. If you dont, I would just buy an external amplifier like BIGTREE recommends since your 777 receiver has pre-outs.

"Sorry Newmanoc, I think you may be mistaken unless you have listened to the Sony 7100ES Receiver."

Well, it is certainly possible that I am. I haven't heard this receiver, and certainly not driving B&W 703's specifically. If you have, then your opinion is far more credible than mine. I only offer my view with such experience as I do have, and with the awareness that going into low ohm loads is beyond that for which Sony receivers are typically well suited.

But if you have not heard this receiver driving the B&W's in question, but only seen pictures of Sony receivers hooked up to B&Ws or read some review citing it was done (a little shy of a true A/B comparision, I'm sure you'll admit), then I would agrue caution is in order before suggesting this is anything remotely like a good idea.

But I think all three of us who have posted thus far are in agreement that the best solution is getting a true multichannel amp and using the current receiver as a processor.

The reason that the 7100es weighs substantially less than your old 777es is because it uses digital amplification as opposed to analog. It still has a massive toroidal transformer but since the digital amplification is something like 90% effecient, it doesn't produce heat like analog amplification does and as such, does not need the massive heat sinks that make up most of the weight in traditional analog receivers.

For what its worth, the 7100es is a lot more powerful than even the 5000es from a couple of years ago thanks to its massive power supply (the old 5000es used switching power supplies and had no toroidal transformer.

With all that said, the 7100es will sound completely different from your 777es as it has a smooth digital sound which is very revealing and clear. Your 777es by comparison will sound more warm in not a touch muddy by comparison. You may find that the digital sound is not for you. Take a listen and see.