Sansui AU-70 proper output tube?

[Tom Bavis]

A further bit of (important) info: pins 1, 6, and 8 on the 6BQ5 are not shown as NC (no connection, but as IC (internal connection). This should be interpreted as "never connect anything to these pins stupid!" as they could connect to any element inside or a feature like the getter or a mica support inside the tube. If they were NC, it would be OK to use as a tie point, but it's not. In actuality, some 6BQ5s and or 7189s do connect 1 and 6 the same as the 7189A. "Short" indications may or may not show on those pins in a tester; ignore them either way. The 6P14 data sheet shows these three pins as unconnected, which is my experience. For all others, assume nothing.

 

[TriodeLuvr]

The RCA 6BQ5 data sheet states "Internal Connection - Do Not Use" on pins 1, 6 and 8. That's pretty clear. Most European data sheets for the EL84 show the pins as "IC," but the Ei sheet states "NC." In any event, I sure wouldn't use them as tie points.

Jack

 

[Mr Boochie]

The RCA 6BQ5 data sheet states "Internal Connection - Do Not Use" on pins 1, 6 and 8. That's pretty clear. Most European data sheets for the EL84 show the pins as "IC," but the Ei sheet states "NC." In any event, I sure wouldn't use them as tie points.

Jack

Really, the 9-pin mini socket tangs don't leave a lot of room to tie parts to, unlike an octal socket. I can't remember where a manufacturer used an empty point on an EL84/6BQ5.

 

[Sansuiman]

Really, the 9-pin mini socket tangs don't leave a lot of room to tie parts to, unlike an octal socket. I can't remember where a manufacturer used an empty point on an EL84/6BQ5.

In principle, I can agree with this. But the possibility still exists that somebody at some point probably did use these "extra" pins as unrelated tie points in a 6BQ5/EL84 design, so it is something that has to be accounted for, regardless. With most tube amps of the time being exclusively point to point wiring, I'd not want to get burned by making an assumption that these "unused" socket pins weren't repurposed out of convenience by the assembler.