Tubes Asylum

Posted by Uncle Ned (i) on July 30, 2000 at 04:06:54:

In Reply to: Was the 7591 tube very common? posted by sherwood on July 29, 2000 at 08:44:25:

1. Was this tube used a lot by audio manufactures?

Yes.

2. Was this tube used a lot by guitar amp manufactures?

Yes.

3. Would a current amp manufacturer use this tube in current models if it was available?

Very unlikely.Except for exotic audio stuff, few like to
use a tube that isn't available off the shelf
at Guitar Center, and even fewer like to use a tube that's
only available from a single source.The fact that some like to use
EF86, KT66 or 6V6 despite that they are only available new from a few
sources, is a testament to the enduring popularity of those
tubes.

If 7591 could be peddled for the same kind of money
as 300B, sure, someone would make these.But as it is,
the typical amp using 7591A sells for less than a
real Western Electric WE-300B goes for.

It seems that most of the other audio tubes used in the 60's are currently in production but not the 7591. Why is this?

7591's were never made in Europe (thus a tube previously made
there can't be easily duplicated), and the demand isn't on the level
of 6550 or EL34.Lastly, 7591 is a royal huge pain to make,
basically to make a 7591, you are taking the filament current
and plate dissipation of a 6L6, the sensitivity of an EL34, and stuffing it in a 6V6-GT bulb. This was quite a feat in 1962, if this
was easy to duplicate today, you'd have plenty of 7591's.

• Triode Electronics