5U4G substitution

[John Caswell]

Hi all,
Various people have asked regarding the replacement of 5U4G valves with 6D22S in the WAD amplifiers. The main advantages are a slow warm up of about 30-40 seconds and much lower cost.
This will will work very well with the amplifiers that use 2 off 5U4G but is not easily implemented in single full wave valve rectifier amplifiers. You can however use the 6D22S in place of the GZ37 in the 300B p-p with just a simple valve base change and a serious saving in cost

To give you an idea, you will require the following -
2 off 6D22Ss valves
2 off B9D valve bases, ceramic preferably, (NOT B9A) top or bottom chassis mount
2 off 1/4" valve top cap connectors
A short length of wire about 12"-18" - preferably PTFE/Teflon
A 1/4" or 6mm rubber grommet
The ability to drill or get drilled a 1/4" or 6mm hole in the chassis.
If there is enough interest I will draw and write up the necessary blurb, pass it to the other moderators for modification/correction and get it placed in the FAQ

John