Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ncusack on December 31, 2013, 01:06:46 pm

Title: Adding EMI filter to an amp?
Post by: ncusack on December 31, 2013, 01:06:46 pm
Hey Everyone,

I recently built a little 18W amp and when I put it together I didn't use an EMI filter on the mains and was wondering if something like this would be a decent choice to add filtering after the fact.

http://www.digikey.ca/product-detail/en/F1199AA06/364-1051-ND/1869583 (http://www.digikey.ca/product-detail/en/F1199AA06/364-1051-ND/1869583)

Aside from weather that's the right kind of part I would also like to know if this will change the mains grounding scheme at all.

Cheers,

Neill
Title: Re: Adding EMI filter to an amp?
Post by: sluckey on December 31, 2013, 02:23:25 pm
Quote
I didn't use an EMI filter on the mains and was wondering if something like this would be a decent choice to add filtering after the fact.
That's fine.

Quote
I would also like to know if this will change the mains grounding scheme at all.
No change. Just run a short ground wire to chassis, preferably the same chassis bolt that the green wire in your power cord is connected.
Title: Re: Adding EMI filter to an amp?
Post by: Willabe on December 31, 2013, 02:38:38 pm
There are many different types at different prices when you look them up.

Some/many are for medical equipment that we don't need and cost more.

I'm not sure which ones are the best for our type of application.


           Brad      :icon_biggrin:
Title: Re: Adding EMI filter to an amp?
Post by: PRR on December 31, 2013, 05:10:17 pm
In our world, we catch more radio-crap on the guitar cord than the power cord.

I suppose if you are running on a generator with bad brushes on a long power cord, brush-hash could exceed crap caught by the guitar cord, and a filter would be useful. But IMHO rarely essential.
Title: Re: Adding EMI filter to an amp?
Post by: stratele52 on January 01, 2014, 04:02:15 am
I never see that in guitar amp and I never need one .

If you want add one ( why ? ) wich one will work best ?