Wouldn't bother.

Standby switches are there for one purpose, so you can take a break during a gig and not have to adjust your volume control. If you need that, it's the only reason to consider adding it. That's why you'll find Standby's only on guitar amps, not radios or stereos, you can pay $10K for a McIntosh tube stereo and there is no Standby on it.

The myth about it preserving tube life is just that, a myth. In the early '70's, some sap misinterpreted information about massive 50,000-watt broadcast tubes and his poor assumption has been repeated ever since. And, even it it weren't a myth (it is), your GZ34 has a slow ramp up, so it takes a while for the B+ to get to full voltage anyway.

What is not a myth is that GZ34 tubes and Standby's don't go well together, which is one of the reasons Nik added those backup diodes at the rectifier socket on all of his layouts.

Why would you leave it on without playing it? Turn it off and save on your electric bill.  

The modifier of not leaving it on "without input" is misdirection. The amp is running hot while playing too. It just means that whenever the amp is on, you wearing down the tubes; when you aren't using the amp, turn it off

EL84's run hot...that's the downside of miniature tubes with small surface area....poor cooling. Add to the the Lightning's Class AB1, cathode-bias design compounds the issue.

If heat is an issue, and you have space, what use use on an EL84 design is this; it is called a "tube cooler" and it has the added benefit of dampening vibration.


A rare exception when you wouldn't want to amp to cool off is recording in a studio...the amp tone changes slightly as the tubes arm up over the first 30 minutes or so, this is neither fast enough nor dramatic enough to note by ear...but once you try and mix guitar parts that were recorded before the amp was warmed up completely with those later in the session, there is a difference.  But...guess what? Warmed up means off Standby with the tubes running and you playing.

If you want a Standby or have a need for one...then it would not be hard to install one.