Amp with speaker INPUTS?? Please explain!


So, I was browsing an amplifier manual, as one does, and the diagram shows four spring clips (R+ R- L+ L-) labeled Speaker IN. (I couldn’t figure out the image hosting thing, otherwise I’d post pics. It’s an AudioSource Amp 300, and the manual is short and easy to find.) I’m not familiar with component connections beyond a couple pairs of speakers and maybe an EQ. But this puzzles me. Can someone please explain when you’d use this? The short “explanation” In the manual is woefully inadequate. 
 

I’m especially interested to know if speakers are at the other end of the wires that connect here. I mean, that would make no sense since speakers don’t send anything that direction, right? 

bricago

@thecarpathian ,

Hec yeah!  It's Cheerwine country!  Are you from here originally?  Wow you've posted a ton!

I spend a lot of time in the South, but New England is my home.

Yes, I've been wasting people's time here for 13 years!

If those receivers didn’t have a pre-out, what output did they use to feed the speaker in? Those speaker in jacks take bare stripped wires. Was there a similar pair of spring clips on the receiver labeled “speaker out?”

 

OP:  Not sure the confusion.  The receivers had no preamp out but they had speaker outs, and often in those days they were simple spring clips.  So the idea was 

Receiver

|--> Extra Amp --> Speaker 

or -------------------------------------

Receiver

|--> Main Speakers

|--> Extra amp --> Second speaker pair

 

In the second case they'd just stick in a second set of wires into the same holes on the receiver.  The extra amp, with high impedance, wouldn't stress the receiver even in parallel with the main speakers. 

That is pretty cool.

I had a Carver Z-Band Coupler for this purpose back in 1991. It allowed me to upgrade my old Harmon Kardon receiver’s speaker terminals with an Adcom GFA 535 amplifier.

I still wonder about the fidelity of this type of setup but I thought it was a great idea back then.

@bbarten  No problem.  I'm good.  I don't live in NC, but you're welcome to stop by if you're in KC.