Hello
I've had an ICBM in my system for quite a while. I installed the ICBM at the same time I got an outboard amplifier. I noticed a hum but thought it was the amp or the electric line. I had the line checked for continuity and voltage. Corrected a bad neutral ground. Swapped out the amp, and the hum is still there. Now I'm looking funny at my ICBM, especially its little transformer. Anyone have any system hum problems caused by their ICBM?

I don't know about the ICBM as a source of trouble (don't have one), but just last week I went through my wiring in search of a fairly annoying hum that had been intermittently driving me nuts for a couple of months. Not a problem with the power from the wall (a dedicated, grounded circuit running through a Panamax power conditioner) or any faulty devices, but the result of power wiring and interconnects getting into a tangle. I cleared up the clutter, re-routed a few power cords to get them away from interconnects, and the problem was solved.

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I'm pretty sure I've posted on this topic before.

My ICBM created a huge hum problem. It's the wallwart power supply. Like most, it's cheap - and noisy.

The solution to all my wallwart problems, was to buy an isolating transformer (otherwise known as a groundloop isolating transformer, or a 1:1 A/C transformer) and to run all of my wallwarts off a power bar connected to it. The one I have is pretty beefy but limited to 300 Watts. But that's not a problem because most wallwarts draw very little current. The only other thing to note is that these transformers typically run hot. It becomes a 20-30 pound hot block of iron and copper in no time. Keep it physically away from other stuff. Use it as a baseboard heater in winter as well. (Only mildly kidding.)

Jeff Mackwood

Thanks fellas

My cabling is very neat, and I separated all power lines (run them through a fat red split loom) from interconnects and speaker wires.

It's definitely a 60 cycle hum, and the only explanation I can come up with is the ICBM transformer.

I've never heard of an isolating transformer. May I ask where you got yours and how much it set you back?

Thanks again. I read the article on curing ground loops and ordered 3 Calrad ground blocker/isolation transformers from my local MARVAC for about $6.50 each. I still think it's a defective ICBM wall wart the only such device on my system. I'll report back.



[This message has been edited by 2x6spds (edited November 03, 2003).]

Nope. No problem at all... but, I already had those described problems in the past with other gear and solved them.

2X6spds,

Apologies for not responding sooner. Lost track of this thread.

Got my isolating transformer at a local electronics / electrical supply store - industrial type (ie. not Radio Shack.) Set me back just over $100Cdn. Every city's got 'em. The transformers come in many sizes. Given the low draw from most wallwarted components, my 300W (output) unit is more than enough for several devices.

Regards.

Jeff Mackwood