I am trying to use the 12 volt trigger on my new Integra preamp to turn on my old Marantz MA700's. How do I do it?

Before you attach it to your camera you must check the trigger voltage first, never use an old flash unit until you check the trigger voltage with a multimeter, most old flash units have a huge trigger voltage that will damage your camera.
Very simple to check the voltage on that Sunpak 622, turn on your volt meter and set it to about 200 volts DC, turn on your Sunpak flash and apply the RED lead to the bottom contact, apply the Black lead to the side of the hot shoe and look for the ground, usually a small metal piece on the side. Now look at the meter, if it shows a voltage of 6 volts or less then it is safe to use on your camera, if voltage is higher, say 12 volts or more, don't use it. A high trigger voltage will certainly mess up your camera in the long run. Even if it has a safe voltage of 6 volts or less, you will only be able to use that flash in Manual Mode, the newer cameras will not sync or recognize an old flash unit.
I have an old Vivitar flash unit that I can safely use on my Canon XTI because the old vivitar has a trigger voltage of 5 volts, safe for all newer digital cameras.

Marantz preamp out, to Carver amp(or line in). Have you tried this and had problems?

The only way would be a voltage selection switch on the back of the unit, or changing pigtail leads on the primary side of the power transformer.

Do you mean just crackling generally or it crackles when you turn it up or down? I have a Marantz PM350, old but still great performance, and I periodically take the volume knob off and spray down the hole with a cleaner/lubricant spray. This does the trick!

The newer surround sound recievers will not work no matter what you try with them the way you have it hool up, they are not design to be useing a turn table on them that has a mgnetic cartridge ,Evan if you buy a phono preamp for it, you are just wasteing your time end money, I was a electronic tech for over 40 years ,Before i retired this summer, End no lots of people who tried to do the same thing your trying to do ,End It would not work,

Do you mean SR-8200? You can't omit the details of a model number if you want a good answer.

Assuming it is...

http://www.retrevo.com/support/Marantz-SR8200-Receivers-manual/id/511ci775/t/2/

Run the 901's with the Active EQ between the receiver Front L and R Pre-Outputs and the mono block amps, one chanel to each.

Pre Out Channel X >>> Bose EQ Amplifer IN, then Bose EQ Amplier OUT >>> Monoblock IN

http://community.klipsch.com/forums/storage/74/1341919/200w%20mono%2005.jpg

I can't find a manual for the MA700. Set them up to a certain volume and then use the speaker setup routines of the SR to match everything up volume-wise. Control will be in the AVR.

Check the ATI website..all the manuals are available there

it is possible that one or both outputs have gone d.c.. try disconnecting both speakers and check across left and right output terminals with a d.c.voltmeter set to 100 volts. no d.c. volts should be present

May be the problem solved here :
http://www.audiotoolers.com/ubbt/ubbthreads.php/ubb/showflat/Number/5316/page/1#Post5316

Unit probably uses fuse type lamps, either 8 or 12 volt filament. Remove one of the lamps and look for voltage rating on end cap. You can order these lamps from Allied Electronics or MCM Electronics online