I think 22-25 people were left, field was 600 or so entries, $45000 for 1st in a $180,000 prize pool (WSOP online tourneys seem to be quite top heavy). No reads on villain at the time of hand.

UTG: (24 bb)
LJ: (50 bb)
HJ: (24 bb)
CO: (53 bb)
BU: (18 bb)
SB : (21 bb)
BB (Hero): (35 bb)

Pre-Flop: (120) Hero is BB with A♠6♠
fold, fold, fold, fold, fold, SB calls 0.5bb, BB shoves

Only dynamic was 10 hands ago SB had limped and folded to my 3.5bb iso.

My question is, should we jam here or check back pre? I think that raising non all in is bad because we can't call any jam from villain and as such we're throwing away the equity of our hand.

I find myself in these spots a lot, and I think at ~15bb or under effective it's a clear jam, but at what stack depth do we start to check back and play flops with A6s?

Thanks