Noise from main system when plug the Crack to power

[Siri]

Get the input signal from McIntosh MX113, noise come from main speakers and go away after unplug power from Crack, it happen whether Crack turn on or off. When use it alone with the signal input from iPhone, iPad there is no noise from the headphone, any idea?

[Paul Birkeland]

Does the rest of your equipment use 2 wire power cords?

[Siri]

MX113 pre. and MC2100 power use 2 wires power cord.

[Paul Birkeland]

If you have some clip leads sitting around, you can use them to connect a screw on each of those components to the chassis of the Crack, and you may find that the noise is all gone.

[Siri]

That's a good idea, thank you, I'll try that tomorrow.

[Siri]

Since this symptom was not happen to solid state headphone amp using either power adapter or 3 prongs power cable, it happen to other tube amp(Dark Voice 336SE)too, both amps(336SE and Crack) when get the signal from sources directly(not from the preamp), sound from my HD600 is perfect even when I route those signals through the vintage Soundcraftmen equalizer, I think it's normal for the tube amp, but why? and how to eliminate that noise when join these amp to the stereo system?

[Siri]

Oh, I try that Paul suggestion to hook up chassis ground between pre-power and Crack amp there is notting change in noise level.

[Paul Birkeland]

You could also try a cheater plug on the Crack. 

[Siri]

I'm new to the word "cheater plug", please shed me some light.

[oguinn]

It’s a plug that goes three plugs to two with a screw tab to go to ground. https://en.m.wikipedia.org/wiki/Cheater_plug