06-18-2019, 09:09 PM
Hi and welcome,
You may want to have a look here: https://philcoradio.com/phorum/showthread.php?tid=17076 It's for a 41-300 but the chassis are very similar.
The output transformer requires to be wired w/proper phasing because of the feedback loop. If not the amplifier will oscillate. To acheive the the proper phasing you may have to reverse the brown and blue wire connecting to the transformer (plate leads). This is done w/the fb loop connected.
You may find that none of the secondary taps will give satisfactory performance when the loop is connected to any of them. Low gain or distortion so to get the best performance connect a low value pot (100-500 ohm is fine) across the spkr voice coil connections. Connect the wiper to the loop and adjust the pot for best results. Once this is done measure the pot and replace it w/5w fixed resistors.
GL
You may want to have a look here: https://philcoradio.com/phorum/showthread.php?tid=17076 It's for a 41-300 but the chassis are very similar.
The output transformer requires to be wired w/proper phasing because of the feedback loop. If not the amplifier will oscillate. To acheive the the proper phasing you may have to reverse the brown and blue wire connecting to the transformer (plate leads). This is done w/the fb loop connected.
You may find that none of the secondary taps will give satisfactory performance when the loop is connected to any of them. Low gain or distortion so to get the best performance connect a low value pot (100-500 ohm is fine) across the spkr voice coil connections. Connect the wiper to the loop and adjust the pot for best results. Once this is done measure the pot and replace it w/5w fixed resistors.
GL
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!
Terry
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