12SN7GT in Crack

[Loon]

I am modding my Crack (when it arrives) to take 12SN7GT tubes.

Can anyone tell me if the following two tubes are equivalent and/or would run in the Crack modded with a 12.6 V DC heater voltage:

12SX7GT
1633

I found the 1633 as equivalent to 12SX7GT on a Tung Sol data sheet for that tube.  I can't find a data sheet for the 1633 though.

Thanks

[Grainger49]

You should always build stock first.  If there are any problems it makes the troubleshooting much simpler.

Looking at this link the 12SX7GT has one direct substitute (CV3697):

http://tdsl.duncanamps.com/show.php?des=12SX7GT

The 12AU7 has several:

http://tdsl.duncanamps.com/show.php?des=12AU7

This is the first place I look to find drop in equivalents.

[Loon]

Thanks Grainger

Don't think I will build stock first this time around as need to punch hole in chassis plate so crack can take octal. 

Will start with 6sn7 then add heater and filament DC voltage regulator so that it can take 12sn7.  Can then use adaptor to use 12au7, which I believe can also be used with a 12.6 V heater supply.

Found a sheet fo 1633 eventually and it needs 25V heater supply.

[Paul Birkeland]

The 12SX7 will be an acceptable substitute in the Crack for the 6SN7.