The ruling to that varies.
The Tag Duels down here are as follows: 16000 vs 16000 Life Points for both teams.
1. Cards on the field is as in "1 field" meaning it just one big field with 10 Monster Card Zones, 10 Spell/Trap Card Zones, 2 Field card Zones (however, 1 Field card may be active on the field) 2 Graveyards, and 2 Fusions Deck Zones. This meaning if I have a face-down Call of the Haunted, I may special summon Jinzo in my partner's graveyard. Or my partner may use my Call of the Haunted to get back his Blowback Dragon. (The field is as 1)
Another Example is for #1:
My Partner and I have an active Messenger of Peace, partner's Standby Phase and he/she can pay for Messenger of Peace if desired. I have the same option if it were my Standby Phase and i can choose not to (the field is as 1)
2. The Deck Zone and "Hands" only the owner's have control of, draw from your deck only and may only use cards in the "Hand" by the controller. Meaning It's my partner's turn but he can't activate my Premature Burial in my hand. (but he/she can however activate my Premature Burial if I were to set it) (the field is as 1)
3. Turn counts proceed as 2 fields, as a normal duel would. Meaning if I have an active Swords of Revealing Light, during the ends of my opponent's turn, it would be like a normal duel. (1on1)
Based on the basic ruling down here, Amplifier would allow you to use Trap Cards regardless of you are not the "actual controller" of Jinzo. (the field is as 1)