I have a Silvertone table radio, Mod 7036 which is transformer powered. It is stamped 25 cycles. I was told it would work on 60 cycles AC; is this true? What would be the effect on the voltages?
Nick

Yes Nick, it will work just fine without any voltage problems. I have a couple of them and they work fine and they run way cooler as well as the power transformer is much heavier than a 60 cycle unit.
Greg

:I have a Silvertone table radio, Mod 7036 which is transformer powered. It is stamped 25 cycles. I was told it would work on 60 cycles AC; is this true? What would be the effect on the voltages?
:Nick

I believe that 25-Hz power was supplied around the Niagra Falls area before WW2.

Greg is correct, a 25-Hz xfmr will have more core iron than a comparably rated 60-Hz model. At 60 Hz, you might be able to reduce the size of the filter caps a little and still have acceptable ripple on the B+. That could reduce wear and tear on the 6X5 rectifier at turn-on.

:Yes Nick, it will work just fine without any voltage problems. I have a couple of them and they work fine and they run way cooler as well as the power transformer is much heavier than a 60 cycle unit.
:Greg
:
:
::I have a Silvertone table radio, Mod 7036 which is transformer powered. It is stamped 25 cycles. I was told it would work on 60 cycles AC; is this true? What would be the effect on the voltages?
::Nick

:I believe that 25-Hz power was supplied around the Niagra Falls area before WW2.
:
:Greg is correct, a 25-Hz xfmr will have more core iron than a comparably rated 60-Hz model. At 60 Hz, you might be able to reduce the size of the filter caps a little and still have acceptable ripple on the B+. That could reduce wear and tear on the 6X5 rectifier at turn-on.
:
:Yes it is a large transformer. I was reading about Nikola Tesla and George Westinghouse who were responsible for the 1st AC power station at Niagara falls. The first installation was indeed 25 cycles and the first city to be powered by AC was Buffalo, NY. Nick
:
::Yes Nick, it will work just fine without any voltage problems. I have a couple of them and they work fine and they run way cooler as well as the power transformer is much heavier than a 60 cycle unit.
::Greg
::
::
:::I have a Silvertone table radio, Mod 7036 which is transformer powered. It is stamped 25 cycles. I was told it would work on 60 cycles AC; is this true? What would be the effect on the voltages?
:::Nick

::
::Greg is correct, a 25-Hz xfmr will have more core iron than a comparably rated 60-Hz model. At 60 Hz, you might be able to reduce the size of the filter caps a little and still have acceptable ripple on the B+. That could reduce wear and tear on the 6X5 rectifier at turn-on.
::

One thing to watch is that the transformer may be too efficent, and sets inteded fro 25 cycles often we designed for 110 volts, vs the 120 we get today.

Measure the filament voltage, and iff too high stick a dropping resistor in there.

Charles' suggestion to check the voltages is good.

I would expect the xfmr losses at 60Hz to be higher than at 25Hz. The copper (winding) losses are the same at either freq, but the core (iron) losses would be higher at 60Hz.

Now, having said this, the B+ should be a little higher at 60Hz because of less ripple, but nothing to worry about. I wouldn't expect the filament voltage to be much different, but do check. The 120V vs. 110V line voltage would be more significant I think.

:One thing to watch is that the transformer may be too efficent, and sets inteded fro 25 cycles often we designed for 110 volts, vs the 120 we get today.
:
:Measure the filament voltage, and iff too high stick a dropping resistor in there.