Looking to warm up your YGL 1? This kit contains a matched pair of JJ EL84's and two ECC83S's with one being current balanced ECC83S 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.