This kit contains a matched pair of JJ EL84's along with an ECC81 for V1, a standard ECC83S for V2, and a balanced ECC83S for the phase inverter in V3. This gives the amp more headroom from the front end which allows you to hear more distortion from the power tubes at higher volumes. Just let us know in the comments section if you're looking for an early breakup, a moderate breakup or a later breakup from the power tubes. If you opt for more headroom we will choose the coolest grades we have available for the power tubes.