[radionut1929]

Well, I looked at the schematic of the Kolster K-27. At first, it appears that the Kolster transformer would substitute for the Philco 511 transformer.

But it won't. Why?

Notice the Kolster transformer's high voltage winding is 600 VCT (300-0-300).

After some searching, I finally found the Philco's ratings. Its high voltage winding is only 375 VCT (187.5-0-187.5).

To use the Kolster transformer would make the B+ run too high throughout the Philco, and would likely cause the B+ on the 71A plate to exceed its design ratings (180 volts max.


You can do what you wish, but I personally would not do it.

Here are rough specifications for the Philco transformer. I can't guarantee the current specification of the high voltage secondary is correct, but 60 mA is greater than the total plate current draw of the entire set which according to Bulletin 5 adds up to just over 34 mA. Bulletin 5 specifies "30 mA per plate" on the plates of the 80 rectifier. Therefore, 60 mA was selected as a nice round figure. Anyone is, of course, welcome to add their two cents' worth to this. The filament currents were obtained from a tube manual - the 1.5V filament current is equal to the total filament current draw of four 26 tubes.

Primary - 125 volts AC, tapped at roughly 110
Secondary #1: 375 VCT (187.5-0-187.5), looks like 60 mA
Secondary #2 (26 tubes): 1.5V, 4.2A
Secondary #3 (27): 2.5V, 1.75A
Secondary #4 (71A): 5VCT, 0.75 to 1A? (0.5A for 71A tube plus additional current of pilot lamp)
Secondary #5 (80): 5V, 2A

Hi Ron,

Ok, I will take your advice and not use the Kolster transformer.
I will just wait until I have enough money to get the transformer rewound.
By the way, do you know where I can get a Philco model 86 junker set?
Please let me know what you can do to put the word out and I will be
thanking you for what help you can offer.

Sincerely,
Radionut