Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Siri on April 06, 2019, 04:16:41 AM

Title: Noise from main system when plug the Crack to power
Post by: Siri on April 06, 2019, 04:16:41 AM
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?
Title: Re: Noise from main system when plug the Crack to power
Post by: Paul Birkeland on April 06, 2019, 06:05:05 AM
Does the rest of your equipment use 2 wire power cords?
Title: Re: Noise from main system when plug the Crack to power
Post by: Siri on April 06, 2019, 07:52:46 AM
MX113 pre. and MC2100 power use 2 wires power cord.
Title: Re: Noise from main system when plug the Crack to power
Post by: Paul Birkeland on April 06, 2019, 01:38:19 PM
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.
Title: Re: Noise from main system when plug the Crack to power
Post by: Siri on April 06, 2019, 05:43:36 PM
That's a good idea, thank you, I'll try that tomorrow.
Title: Re: Noise from main system when plug the Crack to power
Post by: Siri on April 07, 2019, 03:50:49 AM
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?
Title: Re: Noise from main system when plug the Crack to power
Post by: Siri on April 07, 2019, 03:57:53 AM
Oh, I try that Paul suggestion to hook up chassis ground between pre-power and Crack amp there is notting change in noise level.
Title: Re: Noise from main system when plug the Crack to power
Post by: Paul Birkeland on April 07, 2019, 05:20:16 AM
You could also try a cheater plug on the Crack. 

Title: Re: Noise from main system when plug the Crack to power
Post by: Siri on April 07, 2019, 04:49:12 PM
I'm new to the word "cheater plug", please shed me some light.
Title: Re: Noise from main system when plug the Crack to power
Post by: Jameson on April 07, 2019, 05:16:14 PM
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