Subwoofer connection

Do you already have a subwoofer?
If not, look for a subwoofer that has speaker level connections. 
A popular brand such as REL Acoustics Provide such a connection. 

I do have subs w/amps. Just trying to figure out how to connect to receiver withought RCA sub output. Can one connect through a pre out? I’m not sure if I even want a sub for this thing as it’s driving everything I’m throwing at it like Klipsch, Cerwin, and Bose with descent base. Thank you!

@gkelly  is correct, in that a subwoofer with speaker level connections would be the way to go. However, because vintage receivers do not work with banana or spade speaker connectors, speaker level sub woofer connection is not a straightforward process. I doubt you can fit two wires into the small gauge holes, so you may need to connect the sub or subs to the speaker "B" inputs and run A+B output.

Whatever you do, I would first check with REL or whatever sub manufacturer to decide to go with, to make sure it will work without damaging either component.

Pre out should work fine ...

Easy peasy!

You will have to remove the preamp and amp straps. You will need two Y cables. From the preamp out the left y-cable will go to the sub left in and to the amp left in. Vise versa with the right channel!

The two already mentioned should get you connected.  @yogiboy solution if you don’t have high level connectors for your sub.  I think you can also use the Adapter output but not entirely sure of that one.

Either a Y cable on the pre-out jack if you are connecting with RCA cables or if there are speaker level inputs on the sub you can use those, feeding directly from your main speakers. This assumes you do not have a dedicated sub out connection on your receiver/amplifier. If that is present its just a direct hookup. If you use the sub out connection be sure and disable the low pass filter either at the sub or at the receiver. You don’t want to be running both filters as you can get unwanted interaction when you do that. Use one of them but not both. It may be easier to disable the low pass at the receiver as some older equipment may have this set at a default 80 Hz that is not adjustable and you may find integrating the sub into the system difficult. The transition from the mains to the sub may be more seamless with a lower crossover frequency. Generally, the sub will give you infinite adjustability from about 80 hz down to 40 hz which with most affordable speakers will be sufficient enough range to get them dialed in nicely. Good luck and enjoy!

I think I got it guys- Y cable makes 101% sense. This is my first receiver with pre out-n-in and no sub outs, so I didn’t know. All I knew was I didn’t want to use an older sub w/o line level inputs. The Y RCA’s have saved me before! I’m Done with cheap 1990’s 110wpc receivers. THANKS GUYS! 

Tape out. Done!  It's how we used to hook up eq's and such.  There's always output there.

bbarten

Tape out. Done!

Oh, no, you don’t want to connect a sub to a preamp’s tape output. That would feed a fixed level signal to the sub. In the OP's case, Y-cables connected to the preamp out (which is after the volume control) is the way to go.

agree, no tape out for subs ...

There we have it guys, I’ll connect the subs through the pre with the Y RCA. For giggles and grins I’ll also try connecting a sub on my garage stereo through the tape out with monitor just to see how it sounds. I’m sure I’ll be posting again with questions as I upgrade all my 1990’s era equipment to match the silver faced 1280  receiver  Thanks for all the help and everyone’s time! 

Just make sure the sub volume control is way down before you play music from the tape out...