AU-717 Bi-Amp Time!

[javamanad]

I have an AU-717 which I'd like to use as both a pre-amp (for CD input and volume control) and power amp in tandem with another power amp to bi-amp my new Polk RTi 12 speakers. These speakers accept passive biamping as they have internal crossovers.

Question, Can I use the AU-717 to control the volume for both amplifiers (the one built into the AU-717 and another power amp) as well as the pre-amp section of that AU-717 for component connection? If so, which position should the switch on the back of the AU-717 be in?
1. connected
2. direct coupled
3. separated
4. capacitor coupled

I guess I would connect the other power amp via the pre-out, main-in jacks on the back of the AU-717?

Any suggestions would be very much appreciated. Thanks!

 

[whoaru99]

Connected, IMO.

Then run cables from pre out to power amp input.

The volume control of the 717 will control the volume of the external amp connected to the pre out.

However, to be "right" the external amp needs to have the same gain as the amp in the 717, or the balance of the speaker's mids/high to lows will be messed up. Using an amp with gain/level controls would address this so long as the gain of the external amp is not less than that of the 717.

 

[Hyperion]

'Connected' would do it - but wouldn't it be safer to use capacitor coupled - even though this makes interconnection more difficult? (would need to employ something to create 2 x L&R from 1 x L&R i.e. the AU-717 pre-outs).

Just thinking about 2 separate power amplifiers with their inputs directly connected together... - am I being too cautious here?

John

 

[whoaru99]

One pre-out driving multiple amp inputs is seldom a problem because of the high input impedance of the amps.

If some other form was desired, then simple "Y" cables could be used. The common end plugs into the pre-out, then one leg of the "Y" loops back to the main-in, and the other leg goes to the outboard amplifer. Of course, you would need two "Y" cables, one for each channel.