Want to add some warmth and depth to your Stangray? This is our Standard Retube Kit for the Dr. Z Stangray Heads and Combo Amps. The kit includes a matched quad of the JJ EL84's for power, a JJ GZ34, one JJ EF806 to replace the EF86 and one balanced ECC83S for the phase inverter. Mike recommends a JJ gt #6 for power but since we have 30 different grades of the JJ EL84's and we know where the bias point is on these amps, 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.