A51 transformer hum...Need power conditioner?

[jeweltone2002]

Hi,

I recently purchased the A51, and I am getting a hum from the transformer. The hum comes directly from the A51 unit and not through the speaker (it's not a ground loop problem). I send the A51 back to Parasound for repair and they replaced the transformer (very good technical support and RMA service by the way).

I just got the A51 back today, and the hum was reduced to a barely audible buzz. However, when I started using the microwave, the hum came back again. The hum diappeared when the microwave turned off. I live in a 30+ years old house, and so I think the power going to the A51 may not be clean.

I don't want to spend too much money on a power conditioner...maybe $200 or so. What kind of power conditioner will solve this A51 transformer hum? The PS Audio has a product called Humbuster AC. Would this Humbuster help me or do I need some other product?Below is a link to PS Audio website:

http://www.psaudio.com/products/humbusterac.asp

Thanks in advance for everyone's suggestions.

jeweltone2002

[bhuskins]

The Humbuster is a product that I've used in a couple situations similar to yours (old house, etc.) and it worked well. It's a fairly new piece from PS Audio, but so far so good as far as I can say. It might just be the least expensive solution that really would solve the problem. It's a lot cheaper than going with a PowerPlant.

Brent Huskins
Media Design

[jeweltone2002]

Would not using a power conditioner cause any permanent damage to the A51? Since I can't actually hear the transformer hum at my listening position, do I really need to buy one?

jeweltone2002

[Peter Nielsen]

Well, to put matters in perspective, I live in a new 3100sqft house (built 2004). When I turn up the volume, my ceiling light starts to visibly pulsate to the beat of the music :roll:

I wish the US had the same electrical code as in Finland. (In Finland electrical code stipulates to never wire light and outlets to the same circuit. It's been this way since the early 80's). Oh well, in twenty or so years, the technology here in the US will probably catch up to Finnish standards :B

Anyway, my point is that you will probably need a dedicated circuit directly to the main breaker box. Make sure that this circuit is wired with heavy gauge wire to reduce voltage drops (10 AWG).

Peter

[jeweltone2002]

I don't think not enough current is the problem. The A51 hums without driving any speakers (actually, the speakers are not even connected). Also, the microwave is on a different circuit as the A51. I turned off every other electronics in the house except for the microwave and the A51, and the A51 still hums when the microwave is on.

The PS Audio website indicate that if the AC power signal has DC components it will cause the transformer to hum. I don't know if this is the really true or not. If this is true, it means I will need some sort of power conditioner.

jeweltone

[Peter Nielsen]

The PS Audio website indicate that if the AC power signal has DC components it will cause the transformer to hum. I don't know if this is the really true or not. If this is true, it means I will need some sort of power conditioner.

I would guess that this has nothing to do with your house then. Most likely other people in your neighborhood are having the same bad power...

FWIW, from what I understand, the PS Audio 1000 might not be powerful enough to provide for A51 peak power requirements. I'd have a look at the Furman IT reference

Peter

[bhuskins]

Would not using a power conditioner cause any permanent damage to the A51? Since I can't actually hear the transformer hum at my listening position, do I really need to buy one?

jeweltone2002

Nope...

No Damage...It's made to work with big amps.

Brent Huskins
Media Design

[bhuskins]

I would guess that this has nothing to do with your house then. Most likely other people in your neighborhood are having the same bad power...

FWIW, from what I understand, the PS Audio 1000 might not be powerful enough to provide for A51 peak power requirements. I'd have a look at the Furman IT reference

Peter

The PS Audio Power Plant 1000 will have no problem providing the power to the A51. The REAL current draw for the A51 is around 500 watts. My system pulls about 900 watts at FULL power and it includes the C1/A51/A21 and several other pieces of gear.

Brent Huskins
Media Design

[Peter Nielsen]

The PS Audio Power Plant 1000 will have no problem providing the power to the A51. The REAL current draw for the A51 is around 500 watts. My system pulls about 900 watts at FULL power and it includes the C1/A51/A21 and several other pieces of gear.

Then why did they put in a 2400VA transformer? If 1000W is max actual power it will consume, then the transformer is grossly oversized. I think it is that big for a reason... :W

BTW, was that 900W peak measured with a 4 ohm or 8 ohm load on all five channels? (Theoretically, if it consumes 900W at 8 ohms, it will consume 1800W at 4 ohms).

Peter