With the high heat in some parts of the country now,the problem at your brothers may be low voltage.Another thing might be a bad relay,poor connection,or something else wrong with the a/c to cause a major change in the sound.
Often the ones built for surge protection as their main focus don't sound that good.
A good conditioner can make a big difference only after you have your system well tuned and properly matched.
A power conditioner, Furman being the best, is worth the investment, especially with you run tubes.
Furman is by far not the best but I like them. For the money they protect well and don't degrade the sound like others do but Shunyata, Running Springs, Audience, and Theorem are in an entirely different league.
Shunyata, Running Springs, Audience protects and improves the sound to some degree.
I have been very happy with my PS Audio Quintet. Not in the same league as some of the high-end power conditioners mentioned above, but it cleaned up a lot of hum and noise in my system, and made my system sound smoother and more musical. I have not noticed any downside to having my system plugged into it. YMMV!
Blue Circle BC6000 - was able to discern a noticeable difference in dynamics and punch
I've posted this before, and still maintain that I never met a power conditioner that benefited my system. I've tried all that I could find....some are better than others - I found Richard Grey the worst.... Listen to it in YOUR system for a few days, then remove it and listen again.
Stringgreen. I think you need to try a Synergistic research Powercell 10SE. Your negative points will dissapear.
I've tryed many hi end conditioners , but ended up with Shunyata , these units have polished a very great sounding music maker . I also brought home one of there top power cords , I now own 7 . MAX .
I agree on the SR Powercell 10SE - Stringreen - you need to "meet it" and your tune will change (couldn't resist...).
Pure Power APS cetainly made a large and immediately audible difference. I have used it for 2 years now, on all the time, 100% reliable.
The next thing to consider, is adding a Quantum Q4.
Might want to add Running Springs to your list.
I had a Shunyata power conditioner in my system, (although I don't remember which model number), and found it better than most, but I still preferred it out of my system. I feel no need to experiment for "improvements" now.....perhaps a rebuild of my cartridge, but not quite yet.
I use the Belkin PureAV PF60. Retails for about $800, but you can get them for $200 new at this point. I live in an old home, so for me it made a nice improvement. I'm actually getting 120 for the first time ever.
It was most evident in my video system, as the brightness is very noticable. Hope it helps.
I made some interesting experiments. I have both a Shunyata Hydra and a Panamax. I have two systems, one music only in one room and the other a Plasma TV & theater. I put the Shunyata on the music system, then took it out and repeated. My sound was better with the Shunyata, but only a small improvement.
Next I did the same with the Panamax on the Theater. With the Panamax I could "see" and hear better picture and sound.
I put the Panamax on the Stereo and the Shunyata on the theater. I took them in and out and carefully listened. The Panamax on the stereo made no difference and maybe made it sound a tad thick and flat. The shunyata did not do much for the TV and theater but it made slight improvements.
My conclusion was the Shunyata made an improvement in sound quality on stereo and it remains in the system. The Panamax is staying in the theater and you can really see the difference on the TV.
Good Luck, and this is a "LOT OF TROUBLE" by the way.
That's why the Torus is a keeper for me,it's not a little improvement,it's a huge improvement,I use to use separate hydras for components amd amps all on dedicated lines.
Now two Torus(s)20a for components and a 60a for my amps.
Best investment I've made and you really hear it in the music.
We'll worth an audition and you can see that they very seldom come up here for sale or on any other site.
Pricey but worth it if you care about the music.
Can't beleave the guy who took the Shunyata out and said it was better , he didn't even know what model he had, and said he had no more need to seek improvements . Does not sound like a music lover to me . Sounds more like he's trying to save money .
I had two Furmans, just sold the IT 1220 (20 amp), and have owned the Panamx 1000, and several Blue Circle pillows.
I now enjoy a Hydra 8 on the front end, and a hydra 2 on the amps.Both are fed two separate runs of 10 guage from the panels 30 watt breakers.
I also feed the hydras and gear with 3 Annaconda Helix power cords and a python cx.
In my limited experience, the Shunyata gear has made a major improvement in the sound of my system( Ref 3A Grand Veena, Audio Valve Eclipse,Red Draggon Leviathans, Rega P9, Audio Aero Capitole).
I can't see how anyone living in this century with all the crud on the grid finds "wallplugging" superior.
I can't vouch for any of the other top grade power conditioning gear because I have no experience with it.
I would venture to say that it is at least the equal of the Shunyata and if it is, then well worth the money.
In the last few years that I have addressed the power situation,my system has never performed as flawlessly and as naturally as it does now.
The investment was substantial, but the benefits in improvements to my sound in my feeling was more economical than making the upgrade in electronics .
I believe I would have had to at least spend four times as much money on upgraded electronics to match the level of sound my present gear has with the Shunyata system.