Want more warmth and definition? This is our Standard Retube Kit for the Dr. Z Mazerati. It contains a matched quad of JJ EL84's for power, a JJ GZ34 rectifier tube along with a JJ ECC83S for V1 and a current balanced JJ 5751 for the phase inverter in V2. A nice upgrade from the stock tubes, sweet and warm! 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.