Tech Talk – KAY "K503A"(1962) by Bman | Jun 2, 2011 | Uncategorized | 0 comments KAY “K503A”(1962)2-3Watt 1×8″speakerwith ‘radio’ tubes–12AU6, 50L6, 35Z5. Submit a Comment Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Email * Website Save my name, email, and website in this browser for the next time I comment.