Power Conditioner Issue

[Monjul]

I wasn't sure where to post this question so I decided PS's would be a good place.

I have an API Power Wedge 112 that utilizes an isolation transformer for source componnents (2 outlets 120watts) and 4 filtered outlets for power amps 91200 watts).

According to their site faq:


Using a voltage meter to measure the voltage on the isolated outlets of an Ultra Wedge will result in a measurement that is approximately 5 volts higher than the wall voltage. This is normal and is a result of measuring the isolation transformer behind the outlet without a load. When a component is plugged in and begins to draw current the voltage will drop to normal. The voltage of the amplifier outlets on the Ultra Wedge and all the outlets on a Power Pack will read the same as the voltage coming from the wall.


Audio Power - FAQ

The problem is, even when all outlets are used, I still measure 5 volts over the line voltage on the IT outlets. Right now, the line measures a slightly high 123 volts and the IT outlet measures 128 volts.

My question is, can this negatively affect my CD player and/or preamp if they remain plugged into the power conditioner? Can it cause damage if used long term? Thanks.

[Mooly]

Almost certainly not a problem.
Just imagine if your CD player has a transformer with a 10 to 1 step down ratio.
123 volts in would give 12.3 out and 128 in would give 12.8 out... doesn't sound quite so bad now does it

And if that were rectified to DC then that would give 17.4 and 18.1 volts respectively

No problem.

[Monjul]

Originally Posted by Mooly

Almost certainly not a problem.
Just imagine if your CD player has a transformer with a 10 to 1 step down ratio.
123 volts in would give 12.3 out and 128 in would give 12.8 out... doesn't sound quite so bad now does it

And if that were rectified to DC then that would give 17.4 and 18.1 volts respectively

No problem.

Thanks and your explaination certainly makes sense but it does make me wonder why a 1:1 transformer would exhibit this. Maybe they mis-count the windings on the secondary, lol.

[Mooly]

Originally Posted by Monjul

Thanks and your explaination certainly makes sense but it does make me wonder why a 1:1 transformer would exhibit this. Maybe they can't count the windings on the secondary.

It's because the transformer voltage drops as it is loaded so a "compromise" is made during manufacture.

All transformers exhibit what is termed "regulation" which is a percentage by which the output rises compared to when supplying full rated load current.

It can be just as few percent or as high as 50% for tiny transformers.

It's perfectly normal.

[Mooly]

A bit on regulation here amongst other stuff on transformers, section 11.3
Transformers Part 2 - Beginners' Guide to Electronics