I’m often asked about which tubes can be used in my 5E3 D-Lux so I’ve put together the info in one spot for everyone and here it is.
You can swap any of the tubes out at any time in any order with the exception of the power tubes which need to be a matched pair. That’s what is referred to as “tube rolling” and it opens up a lot tonal possibilities.
Rectifiers you can try would be the 5Y3GT with the most sag & compression but also the lowest voltage which means less output. Then there’s the 5V4G which is a step up on voltage which would tighten up the feel of the amp as well as some increase in volume. Finally there’s the GZ34 which would give the amp the tightest feel as well as push the output up another notch.
Power tubes you can try would be the 6V6GT, 5881, or 6L6GC and they all have their benefits. The 6V6GT would be considered the darker of the three but it also has the early break-up and wonderful tone in my opinion. The 5881 is also known as a 6L6WGB and while it’s in the 6L6 family it does have some warm tone and a bit less output that the 6L6GC. The 6L6GC would have the most output but it’s also got a later break-up along with a bright & chimey tone to it.
You can try any 12A*7 or one of it’s variants in the pre-amp for different amounts of gain or tone too.