Toroidal Isolation Power Conditioner

1+ ptss, Equi-Tech uses a balanced topology with their transformers so they cancel noise, any noise just like a balanced pre amp circuit. I use a 1.5 RQ on my low level and digital stuff and it is faultless. It will also last longer than I will. They do make them much larger for amplifiers but it gets expensive and IMHO power amps are less sensitive to line garbage. My opinion here is colored as the electrical company forced me into paying for my own line transformer because of my work shop when I built this house. They did not want me dimming everyone else's lights. So, I probably have less garbage to begin with. I do think the 1.5 RQ made a difference sonically but it is a subtle one. For computer audio it is a must.
I use an Apple Mini with a 6 TB hard drive run by Pure Music and it use to crash every two to three hours or so. Now it might crash once a week. That is a big difference and when I unplug it from the 1.5 RQ it goes right back to crashing every two hours. Go figure. 

Since the OP was looking in the used category for a product, I would cast my vote for BPT . Not only does it use the transformer type that he requested, it also renders a balanced output . In addition, my model has separate shielding for each secondary winding . The end result is the best isolation for each outlet connected to its own secondary . BPT had many options for upgrades as well, but the model that I own (I believe that it is a BPT 13.5? sorry, too many years ago, and the back is impossible to read given its physical location . The damned thing weighs in at 80 lbs.) I remember that it will support a total of 10 amps total, but EACH winding is rated at 10 Amps as well . I know, everybody wants to say that their product is 'built like a tank', but weight alone is not the justifier here . Truly, from the chassis to the individual components chosen, the BPT brad is like few other products that I have ever owned in terms of quality performance and heavy duty plus build .

Also have BPT and second your thoughts. Bought an Equi=Tech to put by the fuse box. Hi efficiency speakers really benefit. 
Best value is the BPT to run your front end. I was lucky to find a used BPT3.5 Sig Plus and yes 80lbs. They come up from time to time.

I know this is an old thread but is there any such power conditioner as the OP was looking for that is affordable? It doesn't seem it should be so custom and expensive, I have a nice one for my DAP.

I'm listening at this very moment to this toroidal.  https://www.decware.com/newsite/ZLC.html

It is quite good and only recently replaced in my main system by a Puritan.