02-23-2009, 02:32 AM
Hello Aaran. I have to disagree. I have had several Canadian Philcos cross my workbench over the yrs that had orig 25-40-50 cycle ac trans on them.Many were already "smoked". The still working 25-40 cycle trans heated up after running awhile on 60 cycles & produced higher B+ voltages in ALL cases, unless a suitable size dropping resistor had been added previously by other techs somewhere down the road. Yes, perhaps this particular orig 25 hz trans ( we are discussing) had internal shorts ( wonder why), nevertheless, I always replace them. To each his own I guess. And if the rectifier tubes plates are getting near short-status, it will in fact make the trans work harder also indeed just before the fireworks show inside the rect. tube.Even the best tube testers can lie, the best test is tube under-load in the set it is working in.
I didnt say a 25 cycle trans "wouldnt work" on 60 cycles!, but in many of my past experiences servicing these sets, I found all them running higher-voltages in B+ here on 60 cycles unless someone previous had added a pwr dropping resistor either at the rectifier socket feeding 1st B+ filter, or by previously lifting & installing a suitable power resistor at the 25 cycle trans CT to chassis ground. Many of these vintage 25-50 cycle sets have had these mods already done many- yrs ago by other techs for the same reasons as I have discussed here, & I found their reasons for "adding" the dropping resistors in the 1st place to work on 60 cycles for a good reason.Those previous "mods" were to drop B+ voltage probs many yrs ago in the US. You bet, vintage 25 cycle trans will work in vintage radios on 60 cycles without any noticable audio probs because vintage tube radios are very-forgiving in "audio". As I stated in my last post, try the same with any solid-state vintage items ( IE tape decks,etc.) designed for 50 cycles vs running on 60 cycles, & you will definately hear the audio distortion due to the cps differences. The last Canadian Philco I had here was a 38-9C, ( equil to US 38-8) I purchased as a parts set on ebay. The B+ dropping-resistor idea had "not" been previously added to that set that had the 25-40 cycle notation plate,and larger size trans & the pwr trans was already "fried" many yrs ago! Wonder why, coulda been the filter-caps also? I installed a good used 60 hz trans on it and saved it.
Im not here to argue at all, Im here to help explain why B+ runs higher here on any vintage 25-50 cycle trans in my previous experiences in servicing vintage radios for years. My local incoming ac line voltage is running around 123-124 volts at 60 cps here depending on time of day usage. And yes,all vintage trannys will heat-up abit, but the 25-40 cycle types really take awhile to build their heat, then "pop",.. your done in many cases if you dont monitor the B+ carefully. I still say using a 25-50 hz power trans on 60 hz, your still " livin on borrowed time"? Just my.02 only.
I didnt say a 25 cycle trans "wouldnt work" on 60 cycles!, but in many of my past experiences servicing these sets, I found all them running higher-voltages in B+ here on 60 cycles unless someone previous had added a pwr dropping resistor either at the rectifier socket feeding 1st B+ filter, or by previously lifting & installing a suitable power resistor at the 25 cycle trans CT to chassis ground. Many of these vintage 25-50 cycle sets have had these mods already done many- yrs ago by other techs for the same reasons as I have discussed here, & I found their reasons for "adding" the dropping resistors in the 1st place to work on 60 cycles for a good reason.Those previous "mods" were to drop B+ voltage probs many yrs ago in the US. You bet, vintage 25 cycle trans will work in vintage radios on 60 cycles without any noticable audio probs because vintage tube radios are very-forgiving in "audio". As I stated in my last post, try the same with any solid-state vintage items ( IE tape decks,etc.) designed for 50 cycles vs running on 60 cycles, & you will definately hear the audio distortion due to the cps differences. The last Canadian Philco I had here was a 38-9C, ( equil to US 38-8) I purchased as a parts set on ebay. The B+ dropping-resistor idea had "not" been previously added to that set that had the 25-40 cycle notation plate,and larger size trans & the pwr trans was already "fried" many yrs ago! Wonder why, coulda been the filter-caps also? I installed a good used 60 hz trans on it and saved it.
Im not here to argue at all, Im here to help explain why B+ runs higher here on any vintage 25-50 cycle trans in my previous experiences in servicing vintage radios for years. My local incoming ac line voltage is running around 123-124 volts at 60 cps here depending on time of day usage. And yes,all vintage trannys will heat-up abit, but the 25-40 cycle types really take awhile to build their heat, then "pop",.. your done in many cases if you dont monitor the B+ carefully. I still say using a 25-50 hz power trans on 60 hz, your still " livin on borrowed time"? Just my.02 only.
