EZ81/6CA4 Rectifier

[David Root]

Datasheets show pins 2, 6, 8 & 9 as "internally connected".
It would be nice to be able to use two of these to bridge a pair of 100 ohm 5W between the plates pins (pins 1 & 7) and the PT secondaries (to get the required resistance across the tube).

Anyone know if These "ic" pins are actually connected to anything?

[Stevem]

If you have the tube on hand just check it, if it is a currently made tube then email the question to the manufacturer or dealer / seller!

[Phil_S]

If there is a chance pins are used for I/C, I'd argue they should never be used as a tie point. In the event of a tube change, it is likely no one -- even you -- will remember that you used a pin for a tie point. Even worse, the person changing the tube won't be checking it for internal connections.

I just checked the spec sheets for RCA, Mazda, GE, and Tungsol. Two of them show N/C for those pins and two of them show I/C. Frankly, I was very surprised at this revelation. Because of this, I would never use those pins as tie points. Check this for yourself: http://tubedata.itchurch.org/index.html

[Leo_Gnardo]

What Phil said ^^^. I'd recommend, fly your 100R's to the socket from tie strip. Not a fan of perching extra components on rectifier tube sockets in any case - the connections are too close together, you may be asking for an arc, who needs that. Same advice for "insurance" SS rectifiers some like to add.

[David Root]

Thanx guys. I'll put in a couple of insulated standoffs or a terminal strip. The EZ81 I'll be using is a NOS '57 Mullard so I don't want no arcing!!

[Firestorm]

My books show it as a 9M base, with no connections to those pins. But you never know.