De-Mystifying Sovtek 12AX7 WA WB WC Variants

I thought it worth the time De-Mystifying Sovtek 12AX7 WA WB WC Variants. Why are there three versions of the Sovtek 12AX7 and why use one versus the other?

One common characteristic of all three types is that they are very low in microphonics.  The “W” in the part number is there to tell us its a ruggedised valve.  Ruggedised valves are made to withstand more vibration than a standard type.  SO this makes them ideal for amp combos where the vibration in the cabinet is higher than an amp head.
Lets look at the three types:
Sovtek 12AX7WA
The WA version has lower gain than the WC- to be more correct the right term is the amplification factor Fender use the WA in amps such as the Blues Jr, Hot Rod Deluxe.  OK so it is branded Groove Tubes, but, it is still a Sovtek 12AX7WA The lower gain makes for an amp with smoother break up. It also helps make the Hot Rod Deluxe volume much more controllable. Some folks report the volume of the Hot Rod Deluxe is all or nothing. Usually generic ( high gain) 12AX7’s have been fitted, and this magnifies the sensitivity of the volume control
Sovtek 12AX7WB
This tube is very similar to the WC version. It has the same gain.  The big difference is that has a  “darker” tone than the other two. This therefore makes it an ideal valve to tame a very bright sounding amp. and the WB has the same gain as the WC
Sovtek 12AX7WC 
The WC version has  the higher gain then the WA. It is also brighter than the WB or WC. It can be used to brighten up what is a dark sounding amp
Usually there are multiple pre-amp stages in heavy rock/ metal amps. The Laney VH 100 is a great example.
The high gain of the Sovtek 12AX7WC pushes the later pre-amp stages into distortion ( “break up”). The chain of 12AX7’s start to break up . As a result the El34’s in the Laney example get a big final push from the pre-amp stages. The lovely hard rock tone magically appears!
Sovtek 12AX7LPS
We need a mention the fourth member of the Sovtek 12AX7 family. It is the Sovtek 12AX7LPS. This is a long plate tube so has a very rich tone. Longer plates result in being more prone to microphonics so it is not a good choice in combo guitar amps. It has a lot of headroom and combined with the rich bottom end and this makes it a superb choice for HiFi amps.
We have all the above valves in stock!
Check out our deals on the Sovtek 12AX7WA WB WC & LPS. We offer the full range of Sovtek preamp valves
We are always available to give advice.