Looking for more warmth and definition? This is the Standard Retube Kit for the Dr. Z Maz 8 Head and Combo Amps. It contains a single JJ EL84 for power, a GZ34 rectifier tube, one JJ ECC81 along with four ECC83S's. Just let us know in the comments section if your looking for max headroom, moderate or an early breakup so we can select a proper grade for the power tube.