Leaving tube amps on.

This is a question I had for a long time. I know it’s not a good idea to leave tube amps on all the time because of tube life and safety reasons. But sometimes I don’t have the opportunity to listen to my system / music for hours at time at one sitting. Sometimes I can only listen to it 45 min - a few hours at a time during the day / night. So my question is would it be better to leave the amps on all day / evening and listen when I can or turn them on / off every time I listen even if is only  45 min at a clip. But to just clarify when I don’t intend to listen that day/ night they will be off. Does turning the amps on / off throughout the day / night do more harm than leaving them on ? Tube life , wear and tear on amps etc. btw I have the Audio Research Ref 750s. Ea amp has 18 KT150 , 6550WE , 6H30.  

128x128Ag insider logo xs@2xtattooedtrackman

@pindac Thank you for clarity on Red plate. I was just gonna ask how important tube bias is and what can happen if not biased. 

@tattooedtrackman  , on bias and red plating,

a few years ago (I think it may have been some time in '20, I had a coupling cap fail on one side of my Cary V12..  I won't try to explain the science or theory of whatever happened within the circuit, because that kind of stuff is beyond me, but the result that I saw was the bias on that side running away high regardless of the position of the bias pot.  (I could back the bias pot all the way off, but shortly after turning the amp 'on' the bias would start climbing out of control on that side.  The tubes on that side got very hot--red plated--and were never the same sounding after I replaced the cap.  I felt the tubes were getting tired anyway, but that event was the last straw and I bought new tubes.  


@tattooedtrackman A number of years ago I bought a preowned tube amp that according to the manual to set the bias you had to put a tiny phillips head screwdriver in a tiny hole until you blindly felt the phillips head screwdriver engage into the phillips head bias screw.  Then turn the screw until the amp shows proper bias for that channel.  Unknown to myself the previous owner had had a bias pot replaced with one with a normal slotted screw.

Well first time biasing I broke off some part of the bias pot and a second later.  I was met with smoke, smell and a real fireworks show. I hit the on/off button and that did nothing to stop what was happening.  I then pulled the plug and the show was over.

If you really saw and smelled what occurs when something like this happens you would not even want to think of leaving your tube amps on and unattended for a long period of time.

Surprisingly the cost to repair the amp was minimal.

What I generally do with tubed gear, which I've done for eons, is turn the gear on around dinner-time (if I plan to listen to music) and off after listening.  On the weekends I'll turn them on earlier and leave on all day and off before bed.


@jetter   Read my post from last year about when I first bought my Ref 750s. I had a tube arc from a bad KT150.