I finally found a perfect solution for this problem. I tried the Mapletree Audio switch box, which admittedly is a little more elegant, but I did some A/B testing and felt like there was a loss of that last 5% of resolution and substance. I do have a very resolving system. I don't think the difference would be noticeable with a mid-level system.
I looked inside and I have to assume that the puny contacts and hook up wire do not do the job (even though they use a high quality rotary switch). So I thought about a hard connection to avoid small contacts and skinny wire. A simple, old school knife switch works best. I felt like I got that last 5% back. I tested two big copper 4PDT switches and this one has the largest contact area and the most copper where it counts: Tatoko Knife Switch Dual power Copper Power Disconnector Switch Semicircular switch 4P 100A https://www.amazon.com/dp/B07V5Z6GP7/ref=cm_sw_r_sms_apa_i_J-8yEbBBR32DH
Remember, if you have a tube amp you should have resistors in the circuit so that the tube amp is never on without a load. Not sure what the load should be. Do your research. I used the resistors that Maple Tree sent with their box. Btw, anyone want a good deal on that box? :)
I looked inside and I have to assume that the puny contacts and hook up wire do not do the job (even though they use a high quality rotary switch). So I thought about a hard connection to avoid small contacts and skinny wire. A simple, old school knife switch works best. I felt like I got that last 5% back. I tested two big copper 4PDT switches and this one has the largest contact area and the most copper where it counts: Tatoko Knife Switch Dual power Copper Power Disconnector Switch Semicircular switch 4P 100A https://www.amazon.com/dp/B07V5Z6GP7/ref=cm_sw_r_sms_apa_i_J-8yEbBBR32DH
Remember, if you have a tube amp you should have resistors in the circuit so that the tube amp is never on without a load. Not sure what the load should be. Do your research. I used the resistors that Maple Tree sent with their box. Btw, anyone want a good deal on that box? :)