It makes sense to use an adapter to make it easier to use an oooolllldddd octal based 50´s amplifier, say an Ampeg or Gibson , with modern easy to find and generally better quality miniatures, say 12AX7.
And a little lightweight tube is reasonably well mounted , through an adapter, over a way larger octal socket.
Now doing the opposite is weird, because there is no real reason to do so, each "new" miniature tube was specifically designed to replace a then popular octal one.
Hey, it´s in the (old) datasheets themselves !!!!!!
Plus it´s mechanically unstable, sitting a large heavy tube , in a small keyless thin pins socket, and with the added leverage added by the adapter which puts center of gravity further away fron the weaker socket. Ugh!!!
Let alone that socket/tube spacing adequate for miniatures will be clogged with way large octals; just try to mount 6 octals in a Twin Reverb chassis
And a little lightweight tube is reasonably well mounted , through an adapter, over a way larger octal socket.
Now doing the opposite is weird, because there is no real reason to do so, each "new" miniature tube was specifically designed to replace a then popular octal one.
Hey, it´s in the (old) datasheets themselves !!!!!!
Plus it´s mechanically unstable, sitting a large heavy tube , in a small keyless thin pins socket, and with the added leverage added by the adapter which puts center of gravity further away fron the weaker socket. Ugh!!!
Let alone that socket/tube spacing adequate for miniatures will be clogged with way large octals; just try to mount 6 octals in a Twin Reverb chassis
It usually just remaps the pins- the 12AX7 can be wired for six volt filaments, and some of these adapters do so.
The real issue is that in all but the most unusual of situations the 12AX7 and 6SN7 are very, very different tubes with incompatible characteristics. the 12SL7 would be a closer match for the 12AX7 and will usually fit and function properly in eachother's place with little to no changes in much other than overall gain.
The real issue is that in all but the most unusual of situations the 12AX7 and 6SN7 are very, very different tubes with incompatible characteristics. the 12SL7 would be a closer match for the 12AX7 and will usually fit and function properly in eachother's place with little to no changes in much other than overall gain.
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