Want more warmth and definition? This is our Gold Pin Retube Kit for the VOX AC4C1. It contains a single JJ EL84's for power along with two Gold Pin ECC83S for the preamp. The gold pin tubes give a smooth breakup with less grit or "hair" on the tone. Just let us know in the comments section if you're looking for an early breakup, a moderate breakup or a later breakup for more headroom in which case we will choose the coolest grades we have available for the power tubes.