Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently May Thu 28, 2020 2:29 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 5 posts ] 
Author Message
 Post subject: From a cool factor or Noir movie
PostPosted: Mar Wed 25, 2020 4:10 pm 
Member

Joined: Mar Tue 17, 2020 11:03 pm
Posts: 69
Don't know what year this is, but from looks alone, what can I say. Check the thickness of this case, is that cast iron? Might have been in auto shops back whenever.

https://www.ebay.com/itm/Vintage-Tube-T ... 1438.l2649


Top
 Profile  
 
 Post subject: Re: From a cool factor or Noir movie
PostPosted: Mar Wed 25, 2020 10:17 pm 
Member

Joined: Jun Fri 19, 2009 6:34 pm
Posts: 9489
Location: Long Island NY
It's an old Jewell counter-top tube tester, presumably from a radio dealer or repair shop where tubes were sold. It basically works on the grid increment or static mutual conductance principle. You set the tube up with the "zero" control so the big meter is on the center mark. Then when you press the "Test" button a volt or two from batteries in the unit is placed in series with the grid which should produce a noticeable change in the plate current. Not terribly quantitative, but very simple--the instructions are printed on the face of the meter!

The "Preheat" they mention on some of the sockets dates this unit to perhaps 1930-31. The early AC operated tubes with cathodes, such as the 24/A, 27, and 35/51 require a considerable amount of time to reach operating temperature--perhaps 30-45 seconds. Testing a number of them could get really tedious. So some tester manufacturers put extra sockets on their instruments which had only the heater pins connected. You would park one tube there to warm it up while testing another. Also made it easier to switch tubes back and forth to compare their readings.

_________________
"Hell, there are no rules here--we're trying to accomplish something!"

Thomas A. Edison


Top
 Profile  
 
 Post subject: Re: From a cool factor or Noir movie
PostPosted: Mar Wed 25, 2020 10:55 pm 
Member

Joined: Mar Tue 17, 2020 11:03 pm
Posts: 69
I imagine with a bit of cleaning those contact switches will last forever.


Top
 Profile  
 
 Post subject: Re: From a cool factor or Noir movie
PostPosted: Mar Thu 26, 2020 12:37 am 
Member

Joined: Mar Tue 17, 2020 11:03 pm
Posts: 69
Mount the power transformer on the top front side, two output transformers on the top where the holes are, tweak the circuitry, add new sockets, and test the machine as you are using it, endless possibilities for stereo amp.


Top
 Profile  
 
 Post subject: Re: From a cool factor or Noir movie
PostPosted: Mar Thu 26, 2020 12:58 am 
Member

Joined: Mar Tue 17, 2020 11:03 pm
Posts: 69
Little close together, but there for a push pull in the top four, and rolling would be easy, preamp down the left side, controls on the right.


Top
 Profile  
 
Post New Topic Post Reply  [ 5 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: PhilF, wazz and 19 guests



Search for:
Jump to:  


































-->


Privacy Policy :: Powered by phpBB