Like the title reads, any one opened 'er up yet and tried some out? Stock, mine has an EH 12AX7 in the left, a JJ ECC81 (12AT7) in the right slot. I do know that ECC81s are 60mU. I have some NOS tubes, a GE black-plate 5751, those are 80mU; and some Mullard Blackburn long-plates ECC83s, 100mU. I wonder if I will fry anything putting a higher gain tube in the right slot?