What Is A Tube Converter And Do I Need One?

It’s a constant paradox with guitarists and their tube amps:  you have to get to a certain volume in order to introduce the optimal distortion level to really make your tone soar, but that volume can easily overwhelm your fellow musicians or a sound engineer, who really need you to lower your volume.  If only you had a device that would enable you to get that great tone at a lower volume level.  You may be in need of a tube converter.

tube converter
Top view heap of old glass vacuum radio tubes valves

A tube converter is a direct plug-in adapter that allows 9-pin EL84 tubes to fit into 8-pin sockets intended for EL34 or 6L6 output tubes.  There’s a couple of other variations available here and there.  

The tube converter is going to redirect the EL84’s pins to map to the correct connection’s to the amp’s 8-pin sockets.  Along the way the signal will encounter a network of resistors to bring the voltage down from the sockets intended for the higher-powered EL34s to the voltage suited for the lower-powered EL84s.  It will also pass through a bias resistor which flips the format from fixed to cathode bias.    You’ll sometimes hear this referred to as changing an output from fixed-bias class AB to cathode-bias class A.

The specific handling of the voltage as it interacts with the vacuum tube and amplifier and how impressive that may be tend to be interesting mainly to the makers as a marketing tactic.  There’s certainly appreciation to be had with the engineering, however to me one of the real values of tube converters comes from the changes in volume and audio quality that they enable!


Since your output tubes are a primary component of the sonic landscape your amp is able to create, using a tube converter can easily introduce some significant improvements to your sound – perhaps more than you were even expecting to be possible!  It’s possible to bring a large-club amp head down to studio or bar gig levels – for example, a 50-watt Marshall-style or Fender-style amplifier can yield an output of around 20 watts with some Yellow Jacket tube converters in place, with a pair of EL34 output tubes.

You might have to do hours of tube rolling or invest in a variety of different tubes to make significant changes to the signature of your amplifier, but a tube converter really speeds that process up.  Because you can find tube converters for a relatively low price, the changes to your tone can be had at a great deal.


There are two things to keep in mind before you go adding a tube converter to your standard setup:

Number one is:  manufacturers (or yourself if you chose to build your own tube guitar amp) intended your amp to be used with a specific type of tube.  Therefore, no amount of applying tube converters will make a different type of tube ideal for your specific amp.

Number two is:  if you end up using a tube converter all the time as an augment of your amp, you should probably just invest in an amp that utilizes the types of tubes you are subbing in via the converters.  In the long run you’ll have a much more efficient, consistent tone.

That being said, a tube converter is an affordable, easy way to really expand the depth of available tone you can get from your amplifier.  If you’ve never had experience with a tube converter, you may as well give it a shot!  As an added tool in your tone toolbelt, it doesn’t get much better than a tube converter.