2x Mullard 12AX7 ECC83 Short Plates Matching Codes Blackburn 1960 I61

I61 B0H (I63 = ECC83 short plate production gen #1, B = Blackburn, 0 = 1960, H = August). Like a warm British jacket of the finest tweed, these glorious tubes have an attractive sweet warmth in their midrange and lower regions.