DIY Audio Projects Forum

Hum, Buzz and Hiss
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Author:  laurie54 [ 14 May 2018, 16:08 ]
Post subject:  Re: Hum, Buzz and Hiss

I recall years ago the "Mark 10" remote control and/or security system for the home owner. (turn lights on off, alarm windows and doors etc). They worked ok but many suffered from the same poltergeists Mark and Bruce suffer from. The suggested remedy was to place a .01uF/1000v disc across the line right in the breaker panel. It worked as long as the source of the noise was on another leg of the hydro feed. Noise was bled off before it corrupted the second 110v leg. Then someone would plug in a vacuum cleaner and it was game over!
It is possible to buy a wall/house receptacle that is mostly aimed at the computer industry but should be included in the audio industry as well. (they come in bright orange only though). It's made for North Ameriac's 220vCT hydro but may be available for 220vac countries not sure. The receptacle had hot and 3 separate gnds. 1= neutral return, 2= 2nd safety gnd return, 3= gnd shield. Most cases "BX" or flex cable is used for the feed so the "gnd shield" is connected to the outer metal jacket of the wire. And it's a dedicated separate feed back to the breaker panel.

Author:  johnnycamp5 [ 09 Jun 2018, 18:12 ]
Post subject:  Re: Hum, Buzz and Hiss

Hello all.
I am a long time lurker, first poster.

I have a new found (approx. 3yrs) love for audio (especially tube) electronics, but absolutely no knowledge for it. I constantly read a lot of info, and enjoy building diy “kits”
I’ll be turning 50 in January, so I doubt that my lack of knowledge is going to change much.

Please forgive my ignorance, which there will be much of lol.

These “poltergeist” pops and crackles from light switches or refrigerators,
or high frequency noise from flourecent lights…
If it’s all ac mains line noise…

Would a balanced power supply unit work to remedy this?
I’m referring to the ones like “eqitech” makes, where they use a huge (depends on wattage) torroid transformer.

Something about a secondary winding establishing 60v+/60v-/ground, vs. 120+/0-/ground.
Supposedly the 60+60- cancel any noise through the windings, I’m guessing similar to xlr balanced lines).

I have read some builders comments, their first impressions were their systems seemed a bit louder at the same volume setting, when in fact they really only lowered the noise floor.

I bought a giant torroid (and a 6 receptacle face plate) for this purpose from “Plytron” a few years ago but never built the unit.
I think it is common to use a bus bar grounding system and (obviously) multiple outlets for the build.

Author:  gofar99 [ 12 Jun 2018, 13:48 ]
Post subject:  Re: Hum, Buzz and Hiss

Hi, I suppose so. My main system uses an APC H1500 power filter/voltage regulator. The regulator bit is somewhat misleading as it bumps it up or down in increments of 5 volts. The filters though work fine. I design and build all my stuff with IEC power input line filters anyhow. We have lots of AC things switching on and off all the time including radiant heat tapes in the ceiling. They are like huge antennas. I don't have any problems with clicks etc from any of it. The only ones that occur are from static electricity when touching things. It is very dry here and they build up rather large. I have grounded touch plates in front of all my turntables to dissipate the charge before touching the tone arms. My gear that is not on the APC doesn't have any issues either.

Good listening

Author:  mwhouston [ 12 Jun 2018, 18:03 ]
Post subject:  Re: Hum, Buzz and Hiss

There are small caps (.0033uf I think) which can be added at certain AC points to suppress clicks. Sorry for the vagueness but I have only sighted the schematic once. Need high voltage rating.

I, like Bruce, have a power filter in most devices. They are compact and at $8 each and a little extra work, why not?

Good grounding techniques can help. I just finished a tube preamp which had a hum and buzz. In the end I connected the negative of the DC filament voltage with the neg of the HT and ran them both to mains earth. The preamp now is dead silent.

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