417 tube

[hpleung]

Hi,

I wanted to check if the 417 tube can be used on the mainline. With an adapter.

Thanks

[Paul Joppa]

Probably. Some issues are:

* The plate impedance is a bit more than twice as high, so it won't drive low-impedance headphones quite as well

* The parafeed capacitor might need a different a different value

* Both tubes are highly prone to oscillation at very high frequencies, so lead dress is critical. It may not be possible to make an adapter that does not oscillate.

[hpleung]

Thanks. I will try and see.

[2wo]

If you're making the adapter yourself, you might be able to add some stoppers or maybe some ferrite beads internally. Might help a little. I have only tried this on a 6sn7 adapter