100% Deaf in right ear. Suggestions for good stereo to mono mixer

I need to find a good stereo to mono adapter . I want to use this adapter with what ever headphone output there is on various devices.
If i did not have roommates that I wish to not disturb I would not bother trying to find a solution.
my current amp is the smsl AD18 hooked up to a pair of rb42’s.
thank you in advance for any suggestions.

How about using Foobar and convert stereo to mono?

That kinda diminishes the quality a fair bit, and there are other plugins that might do better

I know the makie big knob passive has a mono switch that works really well. It just probably wouldn’t work well in this situation unless you are feeding the ad18 using an analog signal, since the device itself is a passive analog device that would need a line level input and output the mono signal. This isn’t exactly what you would be looking for, but it would work for downmixing to mono without major quality loss

I have found this but I am not sure it would work for the typical head phone out jack.

I think it’s for microphones or somthing.
Why the heck is it so expensive sux to be me.
I will look up the makie big knob ty.

This would only work between your source and amp, but you could take both L and R outputs and plug them into the channel that you’re able to hear on the amp.

Devinal Premium Aluminium Alloy RCA Male to Dual 2-RCA Female Gold Plated Adapter, Stereo Splitter Y Audio Cable(RCA F-2 RCA M) (1 Male to 2 Female) https://www.amazon.com/dp/B075HYKJHJ/ref=cm_sw_r_cp_apa_i_DV2yDbMDXE2KE

Not familiar with your amp or HPs so I don’t know what connection options you have but have you looked at things like this? It’s cheap enough that it’s not a big deal if it doesn’t work. I assume there are 1/4" versions as well.