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THE AM BULLETIN BOARD => Technical Forum => Topic started by: W6TOM on February 06, 2016, 06:49:18 PM



Title: Transformer Info ?
Post by: W6TOM on February 06, 2016, 06:49:18 PM
 Went to the California Historical Radio Society Winter Bay Area Swap, nice day, sunny and in the high 50's. Not much ham stuff there and just a few sellers, fun none the less. Bought a bag of parts, inside were two of these transformer kits, any ideas what this was used for??? I assume tube equipment.


Title: Re: Transformer Info ?
Post by: w4bfs on February 06, 2016, 07:05:00 PM
right you are .... that looks like a replacement set of windings for a interstage xfmr that Antique Electronics Supply sold ... a good replacement for Viking II and Dx100 rigs .... cant tell from yer pix but should be small, about an inch or so.... similar to Stancor A53


Title: Re: Transformer Info ?
Post by: KA2DZT on February 06, 2016, 07:06:43 PM
Single plate (like 1/2 12au7) to push-pull grids.  Only problem is where are the laminations??

Fred


Title: Re: Transformer Info ?
Post by: W6TOM on February 06, 2016, 07:12:18 PM
 Size is about 1", the windings and diagram were in a small plastic bag stapled shut with two staples. I have two of these.

 Some pictures from the swap.


Title: Re: Transformer Info ?
Post by: W7TFO on February 07, 2016, 12:47:54 AM
They were meant to 're-populate' your old crapped out I-stage.

I used a few of them over the years..an inexpensive fix it was.

73DG


Title: Re: Transformer Info ?
Post by: kb2vxa on February 07, 2016, 11:54:20 AM
Something you probably know already but what the heck. You can get much improved bass response and save the trouble of building a phase splitter by simply taking the DC bias off the transformer primary thereby greatly raising La. Take the plate lead off the driver tube and feed AC from the plate through a 2uF cap, then feed DC to the plate through a 10K 10W WW resistor. Along with the speech amp mods you've already done your hi-fi AM is now complete.


Title: Re: Transformer Info ?
Post by: W3GMS on February 07, 2016, 10:38:19 PM
Yep, as was said, you need the lamination's and also with the primary to secondary turns ratio, you will be OK only for AB1 operation due to the large step up turns ratio.     

Joe-GMS     
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