I'm pretty sure he got them on E-Bay. Here is the link:
http://www.ebay.com/itm/Genalex-Gold-Lion-NEW-NIB-U77-5AR4-GZ34-Rectifier-tube-Test-NEW-/181256766389?pt=Vintage_Electronics_R2&hash=item2a33bec3b5
http://www.ebay.com/itm/Genalex-Gold-Lion-NEW-NIB-U77-5AR4-GZ34-Rectifier-tube-Test-NEW-/181256766389?pt=Vintage_Electronics_R2&hash=item2a33bec3b5