Big centre Paul Mackey ran in four of the All Whites' 14 tries, while fly-half Luke Richards kicked 13 conversions. Winger Nick Jones scored a first-half hat-trick as Third Division Nantyffyllon were out-classed in all departments, although they fought back in the second half and were unlucky not to trouble the scorers.
Rugby traveller Kevin James scored two tries as Neath mauled Pontypool in an all-Premier League match-up.
The burly winger - brother of Wales international Paul - has turned out for Caerphilly and Ebbw Vale already this season, but yesterday helped the Welsh All Blacks to a one-sided result at the Gnoll.
Neath led 30-0 at the break before easing off in the second half. Promising fly-half Matthew Jones added 14 points with the boot.
In other Cup matches, Rumney scored five tries as they romped past battling Treorchy 30-8, while the deadly boot of Jason Williams helped propel Brynmawr into the next round after a 21-7 win over Rhymney.
Llanelli shrugged off their awful League form with a comfortable 29-7 victory at Beddau, with winger Dan Rogers scoring two tries and Wales scrum-half Mike Phillips adding a third.
Aberavon ran in six tries - including two to Darin Griffiths - as they put Banwen to the sword 48-15, while former Wales international John Devereux's try for Maesteg wasn't enough as they crashed 10-23 at Caerphilly.
In an all-Premier match, Bridgend beat Newbridge 33-17, while Pontypridd players Darren Berry and Dafydd Lockyear both scored hat-tricks in their side's 55-10 win over Gorseinon.
* In the only Welsh Premiership match yesterday, Cardiff winger Johnny Vaughton scored four tries in his side's classy 35-7 win over fourth-placed Carmarthen Quins at the Arms Park.
Cup results: Aberavon 48 Banwen 15, Beddau 7 Llanelli 29, Bedwas 32 Llanharan 13, Blackwood 18 Tonyrefail 10, Bridgend 33 Newbridge 17, Brynmawr 21 Rhymney 7, Builth Wells 13 Whitland 46, Caerphilly 23 Maesteg 10, Ebbw Vale 46 Felinfoel 0, Gorseinon 10 Pontypridd 55, Llangefni 23 Abercynon 12, Neath 49 Pontypool 5, Newcastle Emlyn 9 Bonymaen 20, Newport Saracens 17 Corus 18, Swansea 96 Nantyffyllon 0. Cross Keys and Newport are playing today.