Are there any preamps that can work with 2 amps and a sub woofer?

OP look for a good preamp. Don't spend a fortune. I love Mac. BUT I'm not stuck on stupid either. There are a lot of good preamps..

I have an older Krell 5.1 HT that I really like the build quality. Great stereo playback too. The cool thing, complete sub control and one of the best made remotes on the planet. Class A type circuits. Older DAC and HT but it is a Krell. I paid 350.00 for it 6 years ago.. You can get a 7.1or2 for close to the same now.. Same great playback in stereo..

Speakers and a GREAT preamp, everything else ebbs and flows.. My case more EBB and less flow.. Yes my cup runneth over.. LOL

Regards

Is your sub self-powered? If not, I would advise selling it and getting a self-powered sub with built-in equalizer.

Sub receives l and r from pre-amp, takes the low bass, sends only upper bass, mids, highs out to amp. Importantly it's volume is controlled by the preamp.

Adjust Sub's crossover point; adjust Sub's volume control to match your main's at your most frequent listening level. Now any volume change at preamp goes to sub and amp(s) cohesively.

If in the used market check any of SF line preamps, 4 outputs, 2 balanced, 2 single ended.

G

Are there any preamps that can work with 2 amps and a sub woofer?

Sure. Its not the number of outputs on the preamp, its whether the preamp can drive the combined impedance of all the amp inputs in parallel.


Since your main amps have balanced inputs I would use a balanced preamp. Since subs are usually single-ended input, if the balanced preamp does not have single-ended outputs, I would use a Y adapter for one set of outputs and use the other set to drive a set of Jensen subwoofer transformers to make the conversion from balanced to single-ended (this will also insure that you don't get hum in the subs). The Jensen subwoofer transformers are line transformers that are optimized for subs and so have response to 1Hz to insure there is no phase shift at 20Hz and well below.

3 sets outputs if you use the tape out, that would be a way for many others

https://www.ebay.com/itm/Audio-Research-Reference-6-Tube-Pre-Amp/324525777594?hash=item4b8f3e62ba:g:...