AC 10 power supply chassis

Comment

Comment by David C. Poland on January 26, 2022 at 3:02pm

Norman - thanks for input.

I have found two Amperite 2 pin globe smoked glass regulators over the years of looking:

1 - type 12-10 NIB stating on the box for line fluctuations between 95 and 130 volts for transformer primary between 80-85 volts AC. Tests 4 ohms cold. The stated specs seem about right.

2 - a loose Amperite 14-10 which may be used, and testing 3 ohms cold.

When I get to restoring my AC-10 power supply, I suppose I could try both with amp on a Variac and monitor the amp voltages. I would expect the actual current flow would effect the the Amperite tube life.

I suppose a hefty power resistor in series with the Amperite tube as needed may make it possible to use one of two tubes I have.

Do you understand the significance of the pair of  2 digit tube numbers? 

Any cautions or advice?

Comment by Brad Winder on January 26, 2022 at 12:40am

Thanks Norman!

How hard it will be to find one, or a suitable substitute, is the big question...

Comment by Norman S Braithwaite on January 25, 2022 at 10:06pm

12-20

Norman 

Comment by David C. Poland on January 23, 2022 at 8:00pm

Folks - anyone have the number for the correct 2 pin Amperite voltage regulator tube for the late version Scott AC-10 power supply.??  Or any commentary or experience for this version Scott power supply

This had Scott%20AC-10%20late%20power%20supply.JPG the large smoke glass voltage requlator tube that drops house line voltage to about 80 volts AC to the primary of the power transformer.

Comment by David C. Poland on March 15, 2020 at 6:29pm

Very Nice AC-10 amp !

The tall metal cylinder to the right of the 80 rectifier is a substitute for an 2 pin large smoked glass globe Amperite Self Adjusting Line Voltage Control tube. The primary of the power transformer is designed for 80 Volts AC, per a Scott diagram I have . The Amperite tube acts as a variable resister. From an Amperite tube box I have: "Automatically Controls Line Voltage Line Fluctuations Between 95 and 130 volts"

The Amperite tube replaces the hi-lo switch of earlier production  AC-10 amps.

To protect your power transformer, and as a way to assess incoming line voltage with that Amperite substitute  you have,  when first powering your amp after electrical restoration, monitor the ac voltage presented to the transformer primary (after the substitute) for a reasonable AC voltage and at the same time monitor the B+ voltage is near either:

1) 140 volts DC at the high end of the big ceramic voltage divider. or

2) 135 volts B+ terminal to the receiver

(FYI - I have your version of the late version AC-10 amp (unrestored.) in my collection)

-Dave