Isolation transformer question

I use Plitron isolation transformers for all sensitive electronics. These are industrial grade, not consumer-itis.

I have done a factorial Plitron/ Wall x Aftermarket Power Cord two factor experiment, (in all combinations). Source power was high quality 117VAC half a mile from the nearest commercial installation. No AC, no street lighting running in the neighbourhood. Amps Bryston, speakers Quad ESL, source vinyl.

Best sound was with Plitron isolation transformers. With Plitron, all power cords sounded the same. With wall power, more expensive cords sounded better, monotonically increasing with price (best of these aftermarket cords was $4k).

Just how good can it be? Well, comparing an isolation transformer in front of a medical grade power supply, that power is almost as good as NiCad battery (NiCads are so quiet that they fall below the noise floor of most professional test equipment). You have to listen with utmost attention to hear the difference. That is for powering the most sensitive device, the phono/pre.

Other benefits include protection from power surges. You just can’t expect a 5kg transformer (at most) in a component to protect like a 20kg transformer by the panel. The notion that ANY commercially available amp under 50K is going to protect like that is silly. Even on my big (100 lb of transformers,100 kg of inductors, 1F capacitance) brute force power supply, I use Plitron isolation.

For what it’s worth. YMMV.

I have an Audience AR6 power conditioner. I bought it three houses ago and it made a positive difference. I moved from the big city to a brand new subdivision on the edge of farm country. The people across the street had Moo Cows and the next house rotated crops. Anyway, there, the power conditioner seemed to do absolutely nothing. I left it in for the magnetic circuit breaker, but that’s it.  8 years later, I’m back in the big city and the AR6 makes a very noticeable difference.

YRMV

There are plenty of good reasons to use an isolation transformer including blocking DC, preventing ground loops and getting a quiet neutral. Of course the biggest variable is the quality of your AC in the first place, which is my case is just dreadful. (The corporate parent of my electric utility has paid tens of millions of dollars in penalties for its bribery and fraud schemes, which only drains money that could be spent to improve local infrastructure.)

You need to know that isolation transformers hum. I threw out a 2kv Soundtrapper isolation transformer because the noise of the hum more than counter-acted any perceived benefit to the electronics’ noise floor

lloydc

You need to know that isolation transformers hum.

Mine don’t.

If there’s a hum, that most likely indicates that there’s a gremlin somewhere else in the circuitry. Possibly a grounding issue.   Yet, poorly made transformers can hum - if the windings are uneven or if the lamination deteriorates.