The AM Forum

I?m looking for a choke that will fit in a SDP 1000L amplifier. The manual says its a 4-35hy swinging choke at 500ma and 2000 working volts. It?s a bit tight in the supply so not just any choke will fit. If you have a parts unit with a good choke or a choke that closely matches what might work, please contact me with what you have and what you want for it with shipping to 77429 (Houston, TX area).
Thanks,
Tom N5AMA

You might want to provide the maximum physical dimensions in order for a replacement choke to fit.

The SDP amplifier is not a common amplifier that's found at many operating positions or familiar with amateurs.

Hi Pete,
Thanks for the quick reply! I realize I need to put the dimensions with the request but won?t have access to the amp for another week. I?ll do that asap but in the meantime hope to find a parts unit, however unlikely.
Have a great week.
Tom

Do you have the old choke?  It may be easier to rewind it.

Good morning Chris,
I do not have the original choke and even if I did it looks typical of the nearly bullet proof construction that was common 20 years ago and probably filled with tar. The open frame chokes would be great and I have on rare occasion rewound smaller transformers that otherwise weren?t available, but in this case, I hope to find something that will fit and have close specs that I can use. I guess I could replace it with a larger choke and mount it external to the amp, but I plan to use the amp in its rack mount form and an external choke would be messy.

Thanks,
Tom

The choke space is sort of narrow but tall, skyscraper style.

The choke can be seen to be about the width and height of two 3B28s and there's room above it. Having one of those amps, I've considered the issue of iron replacement before, and am glad I have not had to do it.

The Eldico SSB-1000 appears to have very similar power supply iron in a physical and electrical sense. Its manual is here: 
https://elektrotanya.com/eldico_ssb1000_rf_amplifier.pdf/download.html
Just another sort of potential donor if the parts fit.

Thinking about the choke, IIRC, there are some UTC chokes that are a louvered metal stamped enclosure with terminals on the bottom, air-filled, with an open frame choke core actually fitted inside the box. The S-36 is 4-20H/400mA, and The S-38 is same but 550mA. No idea if any of these would fit, I only learned that the large metal UTC choke box sometimes has quite a bit of air space.