Re: Halicrafters SX17 transformer
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Thanks, Jim.
????????? ? Joe Connor
On Wednesday, August 7, 2024 at 09:53:16 AM EDT, Jim Whartenby via groups.io <old_radio@...> wrote:
Yes, see message # 30485 "Further investigation revealed that the primary of transformer T5 is open." Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
I want to make sure I understand this. Was the Hammond 124A used to replace the interstage transformer??
? ? ? ? ? ? ? ? ? ? ? ?Joe Connor
On Tuesday, August 6, 2024 at 03:03:10 PM EDT, Jim Whartenby via groups.io <old_radio@...> wrote:
John I figured that Richard would chime in about your audio power comment.??
18 watts sounds to the normal ear as twice as loud as that from a 1.8 watt amplifier.? The SX-17 manual mentions that the audio amp puts out 13 watts of "undistorted" audio, whatever that meant before 'hi-fi" became popular.? In any event, if you are just going to listen to speech you may not notice much difference but music or singing might be a different story.??
The reserve power might make the listening experience a bit more life-like especially if your speaker response is pretty flat across the audio spectrum.? Again, the smallest change the normal ear can perceive is 3dB or twice the power.? The difference in performance between a 3 ohm speaker and a 4 ohm speaker is not worth the worry.? The more efficient the speaker is, the louder it will sound.??
I use an old Zenith wood cased bookshelf speaker from a thrift shop with an added 70 volt line transformer using the 10 watt tap.? This is enough to convert the headphone 600 ohm output of a military type radio to the 8 ohms needed by the speaker.? I believe the audio power of the amplifier inside the radio is under half a watt maximum but it sounds just fine for speech! Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
In the end purchasing a new transformer proved to be necessary. The Hammond 124A appears to be working just fine although I doubt that the set is currently putting out anywhere near 18W. After fixing problems in the decoder and IF section (mostly caused by leaky paper wax capacitors that had to be replaced, the set sprang into life and started receiving stations. I implemented an arrangement similar to Franz (HB9HPZ) - so thank you for posting that. I am using a temporary speaker setup which is nowhere near ideal, and perhaps not correctly matched but good enough to test with and I can get good and clear volume from the set, but it does have to be turned up over halfway, maybe two thirds of the way. In any case, it is working so thanks for the comments with advice regarding the transformer.
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