Nice to see you on the forum Rob!
If the loud hum is emitting from the speaker, it's unlikely the output transformer is shot. Much more likely to be the 20uF 450V smoothing/reservoir caps. Given the age of the amp (45 yrs), the cathode bypass cap (25uF/25V) will most likely be u/s too, and of course, it would be a wise precaution to replace the .02 cap feeding the 6V6 ('that cap').
Lots of domestic radios from the late 40s onwards used 6V6 output stage - sometimes, as in the Barker 88, two is push-pull, so in the unlikely event of the OPT being shot, one could be culled from a scrap radio chassis.
(I'm not sure from your post whether you've bought the amp Rob, or are considering buying it - the title of the thread suggests that you're thinking about it and wondering from the description of hum, if it's worth a punt).
This is another instance where someone has an irresistible urge to switch it on to 'see if it lights up' with the risk of seeing it light up spectacularly for a brief instant, sending it to the 'scrapyard in the sky'.
Hope that helps a bit.
If the loud hum is emitting from the speaker, it's unlikely the output transformer is shot. Much more likely to be the 20uF 450V smoothing/reservoir caps. Given the age of the amp (45 yrs), the cathode bypass cap (25uF/25V) will most likely be u/s too, and of course, it would be a wise precaution to replace the .02 cap feeding the 6V6 ('that cap').
Lots of domestic radios from the late 40s onwards used 6V6 output stage - sometimes, as in the Barker 88, two is push-pull, so in the unlikely event of the OPT being shot, one could be culled from a scrap radio chassis.
(I'm not sure from your post whether you've bought the amp Rob, or are considering buying it - the title of the thread suggests that you're thinking about it and wondering from the description of hum, if it's worth a punt).
This is another instance where someone has an irresistible urge to switch it on to 'see if it lights up' with the risk of seeing it light up spectacularly for a brief instant, sending it to the 'scrapyard in the sky'.
Hope that helps a bit.
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
