Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on December 20, 2014, 11:40:53 am

Title: Grounding pin 2 & 7 of an ef86 - is feasible this way ?
Post by: kagliostro on December 20, 2014, 11:40:53 am

A friend has draw an 8 - 9 pin version of the 7 Cylinder amp (with some mod)

(http://i.imgur.com/ZHXH3tY.jpg)

The layout is not yet complete but connecting to ground the pin 2 & 7 of the ef86 tube it was handy to use the shield of the cable of the input signal

is it feasible ?

(http://i.imgur.com/ngrA05e.jpg)

Thanks

K

p.s.: Here the .vsd file

http://www.mediafire.com/view/blsfad43y1jj2jt/9_Cylinder_Layout.vsd (http://www.mediafire.com/view/blsfad43y1jj2jt/9_Cylinder_Layout.vsd)

Title: Re: Grounding pin 2 & 7 of an ef86 - is feasible this way ?
Post by: tubeswell on December 20, 2014, 12:07:11 pm

The EF86 shield can ground at any point in the ground. No current flows through the shield that would affect the ground return.

Title: Re: Grounding pin 2 & 7 of an ef86 - is feasible this way ?
Post by: DummyLoad on December 20, 2014, 12:54:14 pm

yes. have seen,that done on an ampex preamp that uses ef86 first stage.

--pete

Title: Re: Grounding pin 2 & 7 of an ef86 - is feasible this way ?
Post by: kagliostro on December 20, 2014, 01:04:49 pm

Molte grazie Tubeswell & Pete

Franco