Marantz SR8000 Preamp Out / Power Amp In (1 Viewer)

[NHCondon]

Hey all,

I have a Marantz SR8000 which I picked up for cheap and I want to use a DSP module to expand my capabilities in a kind of bi-amp situation.

I am thinking to use 4 channels (plus a sub) to run some Magnepans. I would use 1 channel to power the "woofer" and one to power the "tweeter" so that each gets 105 W, effectively doubling how much goes to the speakers. This would be a simple bi-amping case but I had to go and complicate things a little more...

I also have a Dayton DSP-408 which takes a low level (preamp) signal and sends it to power amp but allows me to control crossovers, eq, time delay, etc. I figured this would be very handy in what I am trying to accomplish with the Magnepans in bi-amp mode.

My question is regarding the Marantz SR8000 in & out jacks on the back: is it as simple as taking the Pre Out RCA jacks to feed the DSP-408 and then back using the 6CH Input jacks?

 

[JohnRice]

A couple things are problems here.

First, and most important, a receiver can only have one active input at a time. It then sends that input to the pre-amp outputs. So, in order to use the 6 channel input, that has to be the selected input, which means the actual source can't be a different input. The result is, you would never get any sound if you selected the 6 channel input. Any other input would produce sound, but the DSP would be bypassed and the bi-amping wouldn't work.

Second, regarding using two amp channels to drive your speakers. Low frequencies require far more power than high frequencies. It is technically true there would be twice as much power available, but in reality most of that increase can't be used. Look at it this way, and I'm just using these numbers to illustrate how it works. Let's say you have a 100 WPC amplifier. There are 100 total watts available, but a maximum of 90 watts is used by the woofers and 10 is used by the tweeters. So if you separate them and have 100 watts available for each, the woofer only has 100 watts available, which means the tweeter will only use a maximum of about 11 of the 100 watts it has available. You don't actually get a 100% increase of usable power, but more like 10%.