Vintage receiver into a subwoofer with a single input

[HTX]

Hi - Long time lurker here!

I searched the forum, but couldn’t find this exact situation. My apologies if I am asking about something that has already been answered many times.

I have an opportunity to buy a friends JBL L10cs subwoofer at a very good price, but I am not sure how I would set it up into my system. I am using a Marantz 2270 receiver, which obviously does not have a sub out connection. Unfortunately the L10cs only has a single “Subwoofer Input” plug, nothing else.

Could I run a speaker-level to line-level converter and then run that output into a stereo to mono converter and then go to the subwoofer input? Somehow I assume that won't work and I am missing something very basic here... lol!

If it doesn’t work (or even if it does), are there any other solutions? Or do I just need to look for a different subwoofer? This is a good deal, and I love how it looks, but if it won’t work then I will have to find something else.

Thanks!

 

[mikehd]

I think your receiver has a pre-out/main-in jumper on the back. You can use the pre-out with a pair of RCA splitters, sending one pair back into main-in, the other pair to a RCA splitter (2 in, 1 out) to the sub's single line level input.

The RCA splitters I use on my Carver receiver are these: https://www.amazon.com/dp/B07TBT6QC4

You'll of course need the RCA cables to connect everything together.

 

[HTX]

Thanks! It definitely has the pre-out/main-in jumper. I never even considered using splitters here. Really appreciate the advice!

 

[bowtie427ss]

the other pair to a RCA splitter (2 in, 1 out) to the sub's single line level input.

That will short the preamp's stereo output to mono.

 

[mikehd]

That will short the preamp's stereo output to mono.

Ah, thanks for catching that.

 

[GordonW]

That will short the preamp's stereo output to mono.

Yes, some sort of "summing node" is needed. Here's a diagram for that:



This should allow the combination of both channel's signals, to the subwoofer.

Here's one that's commercially available:

Amazon.com: SPRODIO Single Stereo to Mono Converter, RCA L/R Audio Adapter Stereo to Mono summing Cable Adapter SC21 : Electronics

Buy SPRODIO Single Stereo to Mono Converter, RCA L/R Audio Adapter Stereo to Mono summing Cable Adapter SC21: Connectors & Adapters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Regards,
Gordon.

 

[Ziinda]

This is where an active crossover helps out. It goes before the amp section though. Some old receivers had low pass and high pass switches which work similar to a crossover and they also had mono switch to combine both channels, then you might be able to bridge those channels but you'll need to check with maker.

 

[HTX]

Yes, some sort of "summing node" is needed. Here's a diagram for that:

This should allow the combination of both channel's signals, to the subwoofer.

Here's one that's commercially available:

Amazon.com: SPRODIO Single Stereo to Mono Converter, RCA L/R Audio Adapter Stereo to Mono summing Cable Adapter SC21 : Electronics

Buy SPRODIO Single Stereo to Mono Converter, RCA L/R Audio Adapter Stereo to Mono summing Cable Adapter SC21: Connectors & Adapters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Regards,
Gordon.

Thanks to everyone for all their help, I appreciate it!

Gordon, is there any chance you could repost the diagram you mention? For some reason I can't get it to show up, only a broken picture icon is there.

Thanks!

 

[GordonW]

Thanks to everyone for all their help, I appreciate it!

Gordon, is there any chance you could repost the diagram you mention? For some reason I can't get it to show up, only a broken picture icon is there.

Thanks!

I saved the image on this computer, and re-uploaded it.

Regards,
Gordon.

 

[HTX]

I saved the image on this computer, and re-uploaded it.

Regards,
Gordon.

Thanks Gordon, I appreciate it!

 

[Lavane]

Yes, some sort of "summing node" is needed. Here's a diagram for that:

View attachment 3586382

This should allow the combination of both channel's signals, to the subwoofer.

Here's one that's commercially available:

Amazon.com: SPRODIO Single Stereo to Mono Converter, RCA L/R Audio Adapter Stereo to Mono summing Cable Adapter SC21 : Electronics

Buy SPRODIO Single Stereo to Mono Converter, RCA L/R Audio Adapter Stereo to Mono summing Cable Adapter SC21: Connectors & Adapters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Regards,
Gordon.

I built one similar to that it works fine.