Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: willhugh on April 22, 2016, 03:02:29 pm

Title: Noise/Distortion from my house
Post by: willhugh on April 22, 2016, 03:02:29 pm
I recently repaired a 1974 master volume Vibrosonic Reverb for a friend. The amp was dirty and had been worked on before. Someone had already recapped the electrolytics and blackface the phase invertevr but  not the bias supply. I fixed the bias supply and biased the output tubes. I also revoiced the preamps the normal for warmer guitar and the vibrato channel for pedal steel. Also i added reverb to b both channels. The amp sounded great except for a little distortion while the note decayed from the pedal steel and some hiss noises while idle. I looked the amp over and could not find anything wrong. I toke the amp to him in Athens Ga. and at his house the amp sounded fantastic. Dead silent and no distortion. I need to know wats wrong with my house. Any help would be welcomed.
Title: Re: Noise/Distortion from my house
Post by: shooter on April 22, 2016, 03:38:03 pm
Quote
I need to know wats wrong with my house.
house wiring, like neutral - hot swapped, or ground not really ground.  Digital noise, modern *smart* phones are horrendous noise makers.  Inductive things like AC motors, frig compressors.  Got a scope?  make a *sniffer coil*,take a BNC coax, cut one end off, solder a copper loop from center to braid, connect the remaining BNC to the scope and sniff around the home, you'd be amazed at the noise!
Title: Re: Noise/Distortion from my house
Post by: willhugh on April 22, 2016, 04:03:48 pm
Are there any good but not to pricey line filters that I could use.
Thanks
Title: Re: Noise/Distortion from my house
Post by: shooter on April 22, 2016, 06:16:30 pm
I just use a descent computer grade buss strip, and I wired a dedicated receptacle back to the mains for my indoor bench, my barn bench would scare the  :cussing: outta any electrical inspector :icon_biggrin:
Title: Re: Noise/Distortion from my house
Post by: willhugh on April 22, 2016, 07:16:26 pm
Thanks