Originally Posted by blumonk
I also believe the 3650 has High instantaneous-current capability (HCC): ±45 amps, whereas the 3600 has HCC): ±35 amp section.
I'd pick the 3600 over the 3650.
The 3650 is also rated for ±35amps (the product information summary sheet lists 45 (along several other misprint specs), though all other documentation lists 35)
The 3600's amplifier section is actually beefier than the 3650, the power supply is larger and there is 25% more secondary capacitance.
I made a fairly thorough list comparing the 3600vs3650 in this thread;http://www.avsforum.com/avs-vb/showt...6#post21574146
Also, 3600 has A-Bus, which is cool for easy to install multiroom. For some reason they dropped it on the 3650.
A note regarding the 3600's A-Bus output - Though not mentioned in the manual, unlike previous A-Bus equipped H/Ks you also need to purchase an optional external power supply if you intend to use it with a single keypad. This power supply connects to the DC jack directly above the A-Bus output.
The integral 24VDC supply was deleted from the 3600's power supply before production.
If you will be using an A-Bus hub (i.e. 'HK' ABH4) off the 3600 to power multiple keypads, a power supply connected to the receiver is not likely required - the hub's power supply will be powering the keypad(s), and powered A-Bus hubs normally do not require power coming in the expansion input (just 12VDC status power, which the 3600 ABus does output even w/o the 24VDC supply connected)
Deleting the integral 24VDC supply obviously saved costs, and it is rare that only a single keypad will be used anyway (thus requiring hub for multiple rooms)
Deleting the A-Bus connectivity from the 3650 entirely saved even more costs. If a hub is being used, a dedicated "A-Bus" receiver output really is not required. The single cat5 line just makes it a little more convenient. E.G. if you wish to setup an A-Bus system with a 3650 (which still has the analog Zone2 outputs), simply connect the Zone2 analog pre-outs to the RCA audio inputs of the A-Bus hub (i.e. ABH4), and run a 3.5mm mono cable from one of the hub's IR emitter outputs back to the receiver's Zone2 IR input. (In most cases a 'status' power connection is not required, as the hub will automatically enable/disable status output to all keypads when audio signal is present at input)
Note: On some *other* brand A-Bus hubs, a local source/RCA input is not used and only expansion input. In these cases a local 'interface' module is normally used, which provides the IR emitter jacks, RCA connection for L/R audio, 'status' power input, and occasionally a trigger output for other sources - this module then provides an "A-Bus" cat5 based output which goes to the hub's expansion input.
Both of the H/K branded A-Bus hubs feature RCA analog input, however.