Hi,
I was curious, I bought a bunch of Valve art 6550A's for these guitar amp projects.6550 Valve Art Picture
Anyway, I was looking at them, Double checking pin outs and discovered that Pin #8 and the metal base ring are connected?
Is this a safety issue?
I had planned on running spring style tube retainers and they come dangerously close to the metal base ring. If it were to contact the ring, wouldn't it defeat the resistor and bypass cap?
Also, Isn't this a shock hazard ?
Trout
I was curious, I bought a bunch of Valve art 6550A's for these guitar amp projects.6550 Valve Art Picture
Anyway, I was looking at them, Double checking pin outs and discovered that Pin #8 and the metal base ring are connected?
Is this a safety issue?
I had planned on running spring style tube retainers and they come dangerously close to the metal base ring. If it were to contact the ring, wouldn't it defeat the resistor and bypass cap?
Also, Isn't this a shock hazard ?

Trout
Hey Gene,
I am looking at my very old Sylvania 6550's. On mine pin 1 is connected to the base ring and agrees with the tube data.
Are you sure you are looking at the right pin? Hold the tube with the bottom facing you and the key on the center post straight up at 12 o'clock. Pin munbering is 1 thru 8 clockwise starting with the first pin after the key.
weird...

I am looking at my very old Sylvania 6550's. On mine pin 1 is connected to the base ring and agrees with the tube data.
Are you sure you are looking at the right pin? Hold the tube with the bottom facing you and the key on the center post straight up at 12 o'clock. Pin munbering is 1 thru 8 clockwise starting with the first pin after the key.
weird...

poobah said:Hey Gene,
I am looking at my very old Sylvania 6550's. On mine pin 1 is connected to the base ring and agrees with the tube data.
Are you sure you are looking at the right pin? Hold the tube with the bottom facing you and the key on the center post straight up at 12 o'clock. Pin munbering is 1 thru 8 clockwise starting with the first pin after the key.
weird...
![]()
WHOOOOPS
Pin 1 is connected, I musta had a brain ***t🙄
Trout
I was out fishing one morning on a nice little lake. I rowed my boat closer to an old man who was pulling them up one after the other... nice fat brown trout. He had his dog with him in the boat, half asleep with his chin resting on the bow. As he was reeling in yet another; he fumbled a bit and the fish slipped off the hook and went back into the lake. The guy looked over at me and said, "Good thing my dog didn't see that."
😉
😉
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