Hi-Gain Amp Input Jack Shielding

General discussion area for tube amps.

Moderators: pompeiisneaks, Colossal

Post Reply
User avatar
Cathode Ray
Posts: 206
Joined: Sat May 26, 2018 3:22 pm
Location: SATX

Hi-Gain Amp Input Jack Shielding

Post by Cathode Ray »

I've seen this done on modded Marshalls, and the amp I'm building(kit) has it as well. It's often done very crudely, using scrap materials.

I can assume it's shielding, but what for ?

RF from inside the amp itself ?


Thanks in advance :!:

Image

Image
Roe
Posts: 1918
Joined: Thu May 31, 2007 2:10 pm

Re: Hi-Gain Amp Input Jack Shielding

Post by Roe »

yes, it is shielding and it works well. Fender even shields the speaker output jacks on newer amps
www.myspace.com/20bonesband
www.myspace.com/prostitutes
Express, Comet 60, Jtm45, jtm50, jmp50, 6g6b, vibroverb, champster, alessandro rottweiler
4x12" w/H75s
SoulFetish
Posts: 211
Joined: Wed Apr 03, 2013 1:50 pm
Location: Norwood, MA

Re: Hi-Gain Amp Input Jack Shielding

Post by SoulFetish »

Roe wrote: Tue Jan 08, 2019 8:05 am yes, it is shielding and it works well. Fender even shields the speaker output jacks on newer amps
Are you talking about the thick insulating board they fit around the two speaker jacks? If you notice where the jacks are located in the chassis, often they are positioned near high voltage nodes and those are there to prevent anyone (children, etc.) from inadvertently sticking something in the speaker input and potentially shocking themselves.
Roe
Posts: 1918
Joined: Thu May 31, 2007 2:10 pm

Re: Hi-Gain Amp Input Jack Shielding

Post by Roe »

that makes sense
www.myspace.com/20bonesband
www.myspace.com/prostitutes
Express, Comet 60, Jtm45, jtm50, jmp50, 6g6b, vibroverb, champster, alessandro rottweiler
4x12" w/H75s
User avatar
Reeltarded
Posts: 10189
Joined: Sat Feb 14, 2009 4:38 am
Location: GA USA

Re: Hi-Gain Amp Input Jack Shielding

Post by Reeltarded »

A better method of shielding is electrical tape with a foil layer encased in shrink wrap.

An even better method is none at all and the jack is installed right at the input grid of the first stage.

:)

#rearinput #pokerintherear
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
User avatar
Cathode Ray
Posts: 206
Joined: Sat May 26, 2018 3:22 pm
Location: SATX

Re: Hi-Gain Amp Input Jack Shielding

Post by Cathode Ray »

Reeltarded wrote: Fri Jan 18, 2019 11:35 am A better method of shielding is electrical tape with a foil layer encased in shrink wrap.

An even better method is none at all and the jack is installed right at the input grid of the first stage.

:)

#rearinput #pokerintherear
I know what shrink tubing is, and have some..

but can you tell me a source for the type of shrink wrap that will work for this little aluminum shield that's about 1-1/2" tall :?:


Thanks.
User avatar
Reeltarded
Posts: 10189
Joined: Sat Feb 14, 2009 4:38 am
Location: GA USA

Re: Hi-Gain Amp Input Jack Shielding

Post by Reeltarded »

you wrap the jack in electrical tape, then foil with a ground wire, then a big shrink thing. The ground wire and the wire shield go to the input ground.. you use smaller shrink butted up to and over the larger stuff to cover the wire tail made at the junction of tye jack and wire.. it looks like a real rat tail.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
User avatar
Cathode Ray
Posts: 206
Joined: Sat May 26, 2018 3:22 pm
Location: SATX

Re: Hi-Gain Amp Input Jack Shielding

Post by Cathode Ray »

Reeltarded wrote: Fri Jan 18, 2019 3:56 pm you wrap the jack in electrical tape, then foil with a ground wire, then a big shrink thing. The ground wire and the wire shield go to the input ground.. you use smaller shrink butted up to and over the larger stuff to cover the wire tail made at the junction of tye jack and wire.. it looks like a real rat tail.
I can visualize it RT.

But what about the "shrink wrap".

Can you link a source for what you're talking about there :?:
User avatar
Reeltarded
Posts: 10189
Joined: Sat Feb 14, 2009 4:38 am
Location: GA USA

Re: Hi-Gain Amp Input Jack Shielding

Post by Reeltarded »

At hardware stores I shop at they have it up to I think 3.25 inch (1.62 wide?) Electrical supply sites I have browsed also had thick and wide shrink.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
User avatar
Cathode Ray
Posts: 206
Joined: Sat May 26, 2018 3:22 pm
Location: SATX

Re: Hi-Gain Amp Input Jack Shielding

Post by Cathode Ray »

Reeltarded wrote: Fri Jan 18, 2019 5:51 pm At hardware stores I shop at they have it up to I think 3.25 inch (1.62 wide?) Electrical supply sites I have browsed also had thick and wide shrink.
Thanks RT.

I'll check it out.
Post Reply