Old tube receiver connection symbols?

I recently acquired a Martel/Rotel FAX-150c tube receiver made in the 1960's. Stamped on the rear chassis beneath the speaker screw connections are the following:

right 0 8 0 8 left

So is the 0 the positive or is the 8 the positive?

Under the FM/AM group the following is stamped on the chassis beneath the screw connections:

FM G AM

Would I use the G ( only ground I see ) to connect the phono ground wire?

The phono inputs are marked MAG and X-TAL so the MAG would refer to a magnetic cart but what is X-TAL?

Quote:

Originally Posted by Poultrygeist

I recently acquired a Martel/Rotel FAX-150c tube receiver made in the 1960's. Stamped on the rear chassis beneath the speaker screw connections are the following:

right 0 8 0 8 left

So is the 0 the positive or is the 8 the positive?

It doesn't matter which is which as long as you are consistent. Logically, I would use 8 as the positive.

Quote:

Originally Posted by Poultrygeist

Under the FM/AM group the following is stamped on the chassis beneath the screw connections:

FM G AM

Would I use the G ( only ground I see ) to connect the phono ground wire?

No, that's for antenna connections. For a phono ground use a screw on the metal chassis. Many receivers have a knurled knob for this purpose but any screw on the chassis will do in a pinch.

It sounds like the receiver has only 300 ohm twin lead connections for FM. The antenna would be connected to the FM & G connections. A long-wire AM antenna would go to the other.

Quote:

Originally Posted by Poultrygeist

The phono inputs are marked MAG and X-TAL so the MAG would refer to a magnetic cart but what is X-TAL?

Correct. The MAG input is used for a magnetic cartridge. XTAL refers to old, obsolete high-output crystal (or ceramic) cartridges that aren't used any more. That input lacks the gain and RIAA curve required for magnetic cartridges.

"0" will be the common which may or may not be floating from chassis ground. As such, "8" will be the hot or "+" and should be in phase with the input signal.