11-01-2008, 11:02 PM
All,
I picked up a Philco 70 with a bad field coil. I'm new to tube radios, and after some research, it looks like the field coil cannot be easily removed to be rewound (let me know if this is wrong). In order to move forward, I'll be hooking up a PM speaker (to use while finishing the chassis work), while looking for a good original (let me know if you've got one).
I've got a few good 8 ohm speakers, and I probably need to build a test speaker for use in the future anyway. I know that I need to get a universal OPT, and it looks like there are some choices from Hammond. Here are my questions:
1) For the purposes of troubleshooting this radio (and potentially other desktop radios), what wattage should I aim for? I was thinking 5W would probably be adequate. This still looks like a $40 - $50 purchase.
2) Has anyone tried this much lower cost ($5 ... too good to be true) alternative: http://schmarder.com/radios/misc-stuff/t-725.htm
It looks to me like this OPT could be used for matching; I have my doubts about performance, but for troubleshooting ... thoughts?
M100C
I picked up a Philco 70 with a bad field coil. I'm new to tube radios, and after some research, it looks like the field coil cannot be easily removed to be rewound (let me know if this is wrong). In order to move forward, I'll be hooking up a PM speaker (to use while finishing the chassis work), while looking for a good original (let me know if you've got one).
I've got a few good 8 ohm speakers, and I probably need to build a test speaker for use in the future anyway. I know that I need to get a universal OPT, and it looks like there are some choices from Hammond. Here are my questions:
1) For the purposes of troubleshooting this radio (and potentially other desktop radios), what wattage should I aim for? I was thinking 5W would probably be adequate. This still looks like a $40 - $50 purchase.
2) Has anyone tried this much lower cost ($5 ... too good to be true) alternative: http://schmarder.com/radios/misc-stuff/t-725.htm
It looks to me like this OPT could be used for matching; I have my doubts about performance, but for troubleshooting ... thoughts?
M100C
