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Transformer hum in power conditioners, what do you do? Power Conditioners
Old 17th July 2011
Gear Addict
ckett's Avatar

Thread Starter
Transformer hum in power conditioners, what do you do?

My current home studio setup is being powered off of a Furman AR-15 Voltage Regulator/Power Conditioner. I am finding that after an hour of having things powered on, I am hearing transformer buzz coming from the Furman.

I used to have a Furman AR-1215 and it did the same thing. Should I just move it into my machine closet and feed everything out to a few power distribution products such as this Furman one: - Pro A/V Product - D-10-PFP

Or should I move up to a higher quality product with a better quality transformer?

What are your experiences and solutions?

Old 18th July 2011
Lives for gear
jmikeperkins's Avatar
Something is not right here. You should not be hearing transformer buzz/hum from your Furman AR-15. It's even stranger that it only happens after it has been on for one hour. I assume that when you remove the AR-15, the buzz/hum goes away? I assume your power is properly grounded? I have been using an AR-1215 for years now and I have never had any transformer buzz or hum from it. My first guess is there is something wrong with your AR-15 but you said you had the same problem with an AR-1215?

A voltage regulator, like the AR-1215, is not a bad thing to have if you have brown outs or voltage fluctuations, because it can correct for those within a certain range, but in Dallas, TX, you probably have pretty stable power and it's probably not absolutely necessary to have a voltage regulator. If you move somewhere else, like a foreign country that has unstable power, then it may be necessary. The link you post is for a Furman D10-PFP which does not offer any surge protection (but does offer a circuit breaker). The normal Furman power "conditioners" do not have transformers in them (open one up and see for yourself - there is not much in the box and nothing in there looks like a transformer) and are really just glorified power strip and surge protectors in convenient rack mount form that sometimes have lights on them. If you want to specifically avoid the transformer in the voltage regulator then just get a normal Furman power conditioner. I bought 5 of the of the $65 Furman M-8x units recently and they work just fine.
Old 18th July 2011
Gear Guru
Changes in acoustic buzz from a power transformer often indicate that the AC waveform is not a pure sine wave, but has harmonics. The cause of this is probably outside of your control - you may find the buzz comes and goes depending on demand on the grid. There are so many switching power supplies (including large industrial motors) that rip the **** out of a pure sinewave. Signs of the times.

I would suggest buying a pure sinewave inverter, and a deep-cycle battery, and a high current DC power supply. This would allow you to construct a good sine-wave uninteruptible power supply. (The cheap UPS are worthless for truely recyling your power - they usually don't boot in until the voltage drops, so they don't achieve what you want to acheive.

I have also wondered about buying two electric motors, mounting them face to face on a baseplate. The input motor would run on dirty AC, and drive the 2nd motor as a generator, which should output pure sinewave with a relatively small loss in power.

An isolation transformer used to establish a clean new earth connection is a good idea. However - any clicks and harmonics pass straight through a transformer (just think of how audio transformers pass any signal). So transformers themselves do diddly squat about cleaning up AC.
Old 18th July 2011
Gear Addict
ckett's Avatar

Thread Starter
Old 18th July 2011
Gear Guru
PS Audio looks a bit like an 'audiophool' company to me ... they have a product to sell for this.

If it's DC on your AC, then a simple isolation transformer will fix this. Worth a try. Of course, the isolation transformer may buzz, but you can mount that outside or somewhere.

I suspect it's more likely to be a distorted sine wave, which would pass through an isolation transformer.
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