I bought a silvertone model 6125, while looking at the schematic it shows a 6J8 tube. Somebody along the line has replaced it with a 6A8 tube.. I don't have a 6J8 tube on hand, is it ok to use the tube in there?
Michael
If you wanted to try it, tubes are forgiving enough for you to test it, but on paper it should not work.
: I'm wondering if a 6J8 tube can be replaced with a 6A8 tube?
: I bought a silvertone model 6125, while looking at the schematic it shows a 6J8 tube. Somebody along the line has replaced it with a 6A8 tube.. I don't have a 6J8 tube on hand, is it ok to use the tube in there?
: Michael
Agree these tubes aren't made for replacement but should work. Pin #6 is a triode plate in 6J8. In a 6A8 it's a screen grid used as oscillator plate. In the case of 6J8 the oscillator grid is used for coupling to mixer stage.
I believe someone who sold you the radio found the 6A8 to operate. 6J8's are harder to find.
Norm
: Hi,
: The answer is "no". 6J8 is a heptode (pentagrid) converter with triode. The 6A8 is just a Pentagrid converter. The problem is with pin 6, on the 6J8, that is the triode output.
: If you wanted to try it, tubes are forgiving enough for you to test it, but on paper it should not work.
:
: : I'm wondering if a 6J8 tube can be replaced with a 6A8 tube?
: : I bought a silvertone model 6125, while looking at the schematic it shows a 6J8 tube. Somebody along the line has replaced it with a 6A8 tube.. I don't have a 6J8 tube on hand, is it ok to use the tube in there?
: : Michael
: Agree these tubes aren't made for replacement but should work. Pin #6 is a triode plate in 6J8. In a 6A8 it's a screen grid used as oscillator plate. In the case of 6J8 the oscillator grid is used for coupling to mixer stage.
: I believe someone who sold you the radio found the 6A8 to operate. 6J8's are harder to find.
: Norm
: : Hi,
: : The answer is "no". 6J8 is a heptode (pentagrid) converter with triode. The 6A8 is just a Pentagrid converter. The problem is with pin 6, on the 6J8, that is the triode output.
: : If you wanted to try it, tubes are forgiving enough for you to test it, but on paper it should not work.
: :
: : : I'm wondering if a 6J8 tube can be replaced with a 6A8 tube?
: : : I bought a silvertone model 6125, while looking at the schematic it shows a 6J8 tube. Somebody along the line has replaced it with a 6A8 tube.. I don't have a 6J8 tube on hand, is it ok to use the tube in there?
: : : Michael
: : Agree these tubes aren't made for replacement but should work. Pin #6 is a triode plate in 6J8. In a 6A8 it's a screen grid used as oscillator plate. In the case of 6J8 the oscillator grid is used for coupling to mixer stage.
: : I believe someone who sold you the radio found the 6A8 to operate. 6J8's are harder to find.
: : Norm
: : : Hi,
: : : The answer is "no". 6J8 is a heptode (pentagrid) converter with triode. The 6A8 is just a Pentagrid converter. The problem is with pin 6, on the 6J8, that is the triode output.
: : : If you wanted to try it, tubes are forgiving enough for you to test it, but on paper it should not work.
: : :
: : : : I'm wondering if a 6J8 tube can be replaced with a 6A8 tube?
: : : : I bought a silvertone model 6125, while looking at the schematic it shows a 6J8 tube. Somebody along the line has replaced it with a 6A8 tube.. I don't have a 6J8 tube on hand, is it ok to use the tube in there?
: : : : Michael
Thank you guys!
After I recap the radio I'll give the 6A8 tube a shot..
Michael
Norm:
I'm stumped again on this radio silvertone model 6125. I replaced a bad 25Z6G tube That was blown with a Good metal 25Z6 tube.
I then replaced all of the capacitors and electrolytics. The Radio's tubes fail to light up!
So I rechecked the tubes just to be sure, and they are still good.. I should mention this is only my third radio I've ever tried to fix so I'm unsure where to look for a problem..
Do you have any ideas for me to try.
Thank you
Michael
: : Hi Michael, The 6A8 should work OK on the broadcast band, it might be a bit marginal on ahort wave. The 6A7 & 6A8 (same tube, octal base) was a clever design that used the second grid as the plate for the oscillator. In fact it wasn't a true grid, just the vertical support wires that picked up sufficient electrons for the oscillator while most passed through to the mixer section. This is different mode of operation to the 6SA7 & 6BE6 pentagrids where the total tube current (usually from the cathode circuit) is used for oscillator feedback. it's used as a normal triode oscillator. There wasn't enough current collected for strong oscillation, particularly on SW and it was also prone to frequency pulling at high frequencies. Try it and see, it will probably be OK & can't hurt. The 6J8 was much more commonly used here in Australia than in the US.
: : Don Black.
: : : Hi
: : : Agree these tubes aren't made for replacement but should work. Pin #6 is a triode plate in 6J8. In a 6A8 it's a screen grid used as oscillator plate. In the case of 6J8 the oscillator grid is used for coupling to mixer stage.
: : : I believe someone who sold you the radio found the 6A8 to operate. 6J8's are harder to find.
: : : Norm
: : : : Hi,
: : : : The answer is "no". 6J8 is a heptode (pentagrid) converter with triode. The 6A8 is just a Pentagrid converter. The problem is with pin 6, on the 6J8, that is the triode output.
: : : : If you wanted to try it, tubes are forgiving enough for you to test it, but on paper it should not work.
: : : :
: : : : : I'm wondering if a 6J8 tube can be replaced with a 6A8 tube?
: : : : : I bought a silvertone model 6125, while looking at the schematic it shows a 6J8 tube. Somebody along the line has replaced it with a 6A8 tube.. I don't have a 6J8 tube on hand, is it ok to use the tube in there?
: : : : : Michael
:
: Thank you guys!
: After I recap the radio I'll give the 6A8 tube a shot..
: Michael