[TR] Triumph Radio question

[LT]

Brian, 4TBTR  is the model number for the 1964 radio.

The Bendix service manual indicates that you connect "the Positive side of the power source to the radio housing and the negative side to the "A" lead"

It also indicates that a speaker with 20 ohms impedance is required. "DO NOT USE A STANDARD 3.2 OHM VOICE COIL"

The radio has an eardrum shattering 2 watts output.

Larry Ternowski

Brian wrote

I have read from this list that radios from earlier Triumph cars (and others of that time) have a ground selector to set the radio for operation in pos. or neg. ground cars.

I have an old Triumph radio (two knobs, 5 push buttons). It is branded Triumph and has the 'book' logo in the display . The display has a 5 to 16 scale, and is AM, I assume. It has is no ground selector.

Written on the case:
4TBTR 009342

Is it safe to assume, as there is no alternative ground setting option, that this radio is for a positive-ground car?

It has three wires. One black, with a bullet connector; two speaker wires Brown and Brown/Yellow.

I want to test the radio to see if it works, and if so, find it a good home. It is in surprisingly good condition, compared to the junk I've seen on ebay.

Can anyone confirm this is positive ground?

Cheers,

Brian