Help! Just finished my Helder TA2020 MKIII and I'm getting buzzing

[CarbonCrew]

I finally got around to assembling my Helder TA2020 MKIII and finished (99% done) it today. Thus far it sounds fantastic, though I am having one issue. This may not be an issue as I still need to buy knobs for the pot and switch, but when I touch the pot adjustment post I get a not extreme, but noticable, buzz or feedback through the speakers.

This is my first project attempt at a DIY amp of any sort and I'm not above stupid mistakes. If anyone has any idea as to how I might remedy the problem I'd love to hear some suggestions.

Thanks,
Chris

 

[DigitalJunkie]

Grounding the body of the pot/switch should fix it up. 🙂

 

[parb]

my guess is that you need to connect the body of pot to ground. it should have come with a ground lug, a round piece that goes over the axel of the pot and has one end with a "pointy tip" on it. solder a piece of wire to the tip and connect the wire to ground. mount the lug on the inside of your box but on the volume knob axle itself and i suspect you will find that this will make your amp quiet.

 

[nigelwright7557]

I always use metal cases for my audio so it acts as a screen.
It should always been earthed.

 

[CarbonCrew]

Yeah I would have liked to have used a metal box. This being my first amp project, I was trying to keep it cheap in case it went bust.

I'll ground the pot and give that a go. Thanks for the suggestions.

 

[tomocapi]

RIFA PHE

Hi, my friend gave me a Helder hifi ta2020 MKIII and I´m trying to put it together. Along with all the parts, there´s a RIFA PHE 426 300 (100nKBRD) capacitor but I don´t have a clue of where it goes in the amp. What does it do anyway? Thanks!