All of the Retube Kits below are Low Output kits and these kits use the JJ EL844’s for power. These are completely different tubes than the stock tubes your VOX AC30C2 came with. The JJ EL844’s are a proprietary tube that JJ Electronic built at the request of Eurotubes.
The dissipation of the JJ EL844 is 25% less than a standard EL84 so using the EL844’s will reduce the power a little in your amp.