Need an explanation!

Hello all,
I am a lurker in the Outlaw area and I am trying to figure something out. I am a hobbyist and have not upgraded for 4 years.

I have a Denon 7.1 receiver (4 years ago it was about $1200 not sure of the model... 3801?).

I have eyed the amplifiers here, but how does that work? I would still need to use my Denon, correct? How do I stop using the Denon amplifier and use the 7700?

Just curious. Would I hear a difference?

Thanks

Yes, you would still need the Denon. On the rear panel of the receiver, there is a group of outputs called "pre-amp outputs". It's not available on all receivers, but above a certain price point it is standard - and the $1200 price point qualifies as above that price point. By connecting an amplifier like the 7700 or 7200 to the pre-amp outputs on the receiver, you would cease to use the receiver's built-in amps to power your speakers and would instead use the separate amp. (That means that when you hook the amp up you'll also need to move the speaker connections from the receiver's binding posts to the amp's binding posts.)

Would you hear a difference. Yes, I would expect so. The amps in a receiver are subject to an assortment of limitations imposed by available space and available budget. A separate amp like the 7700 tosses those limitations out the window by dedicating all of the space to amplification and including a large power supply. If you look at internal pics of the Outlaw amps, you'll see some large transformers - that's the heart of the power supply, converting 120VAC to a lower voltage that is suitable for audio amplification. Compare that to a picture of the inside of a receiver, and you'll see that the power supply is drastically smaller. That means the receiver has less ability to respond quickly to transients that require surges in current and the ability to drive difficult loads such as low-impedance speakers. There are other reasons to go with separate amplification, such as isolating the lower power signals of the pre-amp section (audio inputs, DSP, and so forth) from the higher power signals produced by the amps, but that gives you some idea of why folks are often drawn to separates.

Thanks for the reply! That is the info I needed. What is the big difference between the 7700 and 7200?

The big difference is the internal architecture of the amplifiers. The 7200 is a single ended amplifier while the 7700 is a balanced design. The 7700 basically uses two amplifiers on each channel operating with opposite polarity with the speaker connected across the outputs. The 7200 has a single amplifier for each channel with the speaker connected between the output of that amplifier and a neutral reference.

The balanced design has some advantages. It's possible to use a lower voltage power supply to get the equivalent power output. For equal quality components the slew rate (maximum rate of output voltage change) will be double that of a single ended amplifier. Any asymnetries between the + and - sides of the amplifier will be cancelled.

The drawback is basically the increased expense of the additional circuitry.

Please help me with this as my searches have produced conflicting answers. Is the 7700 a "true" or "fully balanced" design or does it have single ended structure terminating in balance XLR jacks. I want to mate one up with a 997 when they are released and utilize balanced cables but it would be good to know the facts. Thanks very much

Mahansm gives a pretty good description of how the 7700 (and the 7500 and 7900, for that matter) works. It is a balanced design (Outlaw refers to it as differential, which gets you to the same place basically.) The 990 and other surround processors that include balanced outputs are pretty much all single-ended designs, though, and I'd expect the same from the 997.