• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Heater Transformer - too much voltage

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glass-ware_2239_781607


I don't have a schematic for this power supply, but you can see that resistors are used in series with the 1N4007 diodes. To what purpose?
 
Let me guess your transformer is a 12-0-12 and you're using a bridge rectifier. Then, no luck. Choke input won't give you enough volts. Another post with wrong info from me then and that makes four, where do I get the medal? 🙂
 
The rectified DC from the replacement PT (after diodes, before CRC) puts up about 36vdc rather than 28vdc as spec'd on the drawing.

Is the 36vdc with or without any valves plugged in?

If it is with valves, then yes, you need to loose some volts.

If it is without, then you don't yet know how many volts you need to drop, since the voltage will fall when current is drawn, and possibly to the level where no additional voltage dropping is needed.
 
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