Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jonas on December 21, 2023, 09:47:32 am

Title: Gibson Rotary tone control
Post by: Jonas on December 21, 2023, 09:47:32 am: Does anyone know which Gibson model had the passive rotary tone switch? The one without the inductors / choke......

I cannot seem to find it.
Title: Re: Gibson Rotary tone control
Post by: sluckey on December 21, 2023, 11:13:52 am: There are 266 schematics PLUS the Gibson Master Service Manual in Hoffman's schematic library. Take a look.
Title: Re: Gibson Rotary tone control
Post by: scstill on December 21, 2023, 11:32:09 am: interesting design did not know it existed until now (30sec search on google :-)
Guys are also selling varitone switches on ebay and such
https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga_80_varitone.pdf
Title: Re: Gibson Rotary tone control
Post by: kagliostro on December 21, 2023, 05:25:28 pm: Unfortunately the ga_80_varitone has a 15H inductor on the Tone Control

Franco
Title: Re: Gibson Rotary tone control
Post by: Jonas on December 22, 2023, 12:48:00 pm: Thanks guys! I thought there was a different tone circuit without the inductor.
Title: Re: Gibson Rotary tone control
Post by: kagliostro on December 22, 2023, 01:25:17 pm: Are you sure it is in a Gibson amp ?

I remember an Ampeg if I'm not wrong

Franco
Title: Re: Gibson Rotary tone control
Post by: Jonas on December 22, 2023, 01:54:06 pm: I'm not sure if it was a Gibson or not.... sorry for the wild goose chase!!!
Title: Re: Gibson Rotary tone control
Post by: kagliostro on December 22, 2023, 02:19:31 pm: Were you looking for something like this ?

(https://el34world.com/Forum/index.php?action=dlattach;topic=30120.0;attach=104860;image)

Franco
Title: Re: Gibson Rotary tone control
Post by: shooter on December 22, 2023, 04:32:59 pm: Franco that schematic hurts my brain :laugh:
for fun, draw individual schematic circuits for each switch position :icon_biggrin:
Title: Re: Gibson Rotary tone control
Post by: kagliostro on December 22, 2023, 04:48:21 pm: That is in an Ampeg B15 S amp

Franco
Title: Re: Gibson Rotary tone control
Post by: tdvt on December 22, 2023, 05:22:57 pm: Quote from: shooter on December 22, 2023, 04:32:59 pm
Franco that schematic hurts my brain :laugh:

Before I even saw your comment, I thought the same thing.. :icon_biggrin:
Title: Re: Gibson Rotary tone control
Post by: shooter on December 23, 2023, 05:51:10 am: Quote
Ampeg

:laugh:
I took on a super echo twin, I'm sure the draftsman was smokin in the boys room. found a redraw so well done it brought tears to my happy eyes
Title: Re: Gibson Rotary tone control
Post by: Jonas on December 23, 2023, 04:32:22 pm: Thank you kagliostro that is not the one I was thinking of but a good one to try indeed. Will need to draw it out first.......... good exercise for my squirrel brain :laugh: