Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on May 01, 2011, 05:45:03 am

Title: Good Old italian tecnology - no more nowadays
Post by: kagliostro on May 01, 2011, 05:45:03 am

This is a very old Geloso potentiometer

as you can see the wiper didn't touch the carbon surface

between there was a thin metal strip

turning the knob moves the contact without the parties crawl

Unfortunately, these pots are not made more

I must say I was pleasantly surprised to see something done so

Kagliostro

Title: Re: Good Old italian tecnology - no more nowadays
Post by: PRR on March 02, 2019, 12:42:45 am

Geloso had a long history, in America also. Here's 1930 at Pilot Radio company (huge but suffered in the 1930s).
https://www.americanradiohistory.com/Radio_Design.htm
Spring V3 N1

Title: Re: Good Old italian tecnology - no more nowadays
Post by: sith on March 02, 2019, 07:42:26 am

oh I have old G1/1110 that needs much of TLC, and I plan to restore it someday, but it's story for another time...

Title: Re: Good Old italian tecnology - no more nowadays
Post by: shooter on March 02, 2019, 07:51:15 am

I love that it has an "infallible distortion meter" China don't got 'em  :icon_biggrin:

we used a piece of equipment on the Radars that was about that big, and heavy, used for measuring waveguides.

Title: Re: Good Old italian tecnology - no more nowadays
Post by: Tbone55 on March 02, 2019, 08:51:08 am

And now we are paying the price for giving away our technology in exchange for cheap labor.

Title: Re: Good Old italian tecnology - no more nowadays
Post by: PRR on April 18, 2019, 04:13:20 pm

> turning the knob moves the contact without the parties crawl

Here's what looks like the same idea from another company.

Surely both products vanished because nobody will pay $1.50 if there is a $1 pot available.
https://www.americanradiohistory.com/Archive-Radio-Engineering/30s/1930/Radio-Engineering-1930-01.pdf

Title: Re: Good Old italian tecnology - no more nowadays
Post by: kagliostro on April 19, 2019, 06:34:09 pm

Many Thanks PRR

I like those old prints


Franco