Wrong equivalents.

Hello.

Just to let you know that the 6B7S_Aus is a variable mu version of the 6B7 and is not "identical to" at least some of the other valves in that list.  Certainly not the 6B7S with is not variable mu and is spray shielded.  Could someone correct this?

Regards, Stuart

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Hello Stuart,

I removed this confusing lot of more or less similar or equivalent types.

One should always avoid posting excessive links of minor important similar or equivalent types each other.

Btw. the 6B7 is also vary µ and is “mother” of the 6B7 / 6B8 family, the Rogers 6B7S is vary µ too, as merely a spray shielded version of the 6B7.

Best Regards,
Jacob

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Hello Jacob.   The 6B7 and 6B8 are described a "semi-remote cutoff types", whereas the 6B7S_Aus is described as "super control".  In fact, the pentode section of the 6B7_Aus has the same characteristics as that of the 6F7, which is not the same as the 6B7.

The 6G8G has the same characteristics too, which is why it is not simply called the 6B8G.

If you look at the curves, the 6B7/6B8G has a transconductance of about 350 uS at -10V G1 (anode = 250V, screen = 100V), whereas the 6B7S_Aus is 420 uS under the same conditions.

Also, the 6B7/6B8G is pretty much cut off at G1 = -12V, whereas the 6B7S_Aus/6G8G has an extended cutoff to -40 volts.  I can scan the curves, if you want.

In short, if you substituted a 6B7 for a 6B7S_Aus, you would likely get distortion on strong signals.  They are not identical.

Regards, Stuart

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Hello Stuart,

I've modified records and links about 6B7S_Aus and 6G8G.
Btw., most documents shows -21 volts as cut-off voltage for 6B7 and 6B8-G.

Best Regards,
Jacob

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