Guitar tube amp design

I AM CURRENTLY IN THE PROCESS OF DESIGNING A SIMPLE GUITAR AMPLIFIER WITH SOME OLD TUBES BUT AM HAVING TROUBLE WITH SOME COUPLING AND FEEDBACK ISSUES.  ANYONE FAMILIAR WITH TUBE AMP DESIGN FROM YESTERYEAR IS WELCOME TO COMMENT ON THIS THREAD AND MAYBE TOGETHER WE CAN COME UP WITH A KICKIN' GUITAR PRACTICE AMP THAT WORKS!!

                                                         THANKS!!

                                                            MR. SID