SMPS buzzing?????

I have four 14v SMPS's that I put in series to make a 28-0-28 supply for some 41hz.com AMP-1B's. The problem is when I connect my bulk capacitors to the supplies there is a strange buzzing that comes from them that doesnt stop until there is a load of a couple amps applied.

The setup works perfectly fine with and without the caps attached, but the supplies only buzz when they are connected:confused: . Voltages between the supplies vary about 0.2v, is this a problem?

Oh, and they will also make the noise if I connect just one cap to one supply.
 
Ok I fixed the buzzing but in a very strange way, and I have no clue what it did to actually fix the problem.

I just put a very low resistance in series with the power wire to the cap.

I dont have any low value high wattage resistors so I used a piece of NiCrome wire. The piece of wire is 2" and has a resistance of about 0.5 ohms.

If no one sees a problem with the way I'm doing this I guess this will be my solution. The NiCrome wire can handle hundreds of watts of heat so I dont have to worry about it burning up like a resistor would.
 
Thanks Eva, a simple statement from you like "nothing bad" is extremely comforting to me.

The DIY resistors seem to be doing the trick. After playing a 20hz sine wave near clipping the makeshift resistor gets pretty warm, but it doesn't glow red so thats good. I still don't know why such a small amount of resistance in series with a cap fixed whatever was wrong, but I guess it doesn't really matter why as long as it works.

Here's a pic of my DIY resistor and the complete test setup....... on the carpet no less. :shhh: don't tell Mrs. Anonymous, shes away for the weekend.

wire.jpg

testsetup.jpg