[JakeJ]

Good advice from all.  I'm not familiar with your preamp but since you have it on top of your cabinet I'd say you have nothing to fret about other than a few extra hours put on the tubes, although if there was no signal present then even that is negligible.  Chassis warmth may be due to solid state regulators inside?  The rectifier does pass the most current so it will be hot and maybe it heats the transformer and chassis by mechanical transconduction.  ( I just made that up.  )

Boy, those meter dials in Fullrangeman's post made me dizzy!  If that was my meter I'd be freakin' out about the bill that's coming.

[Lord Soth]

Hi there,

I am the owner of a Decware CSP2+ too (pun intended).

Yes, your fears are unfounded.
I always leave my CSP2+ for over 24 hrs in order to burn-in and condition NOS tubes which have been unused for many decades.
So this is perfectly safe. The sides of the amp can still be handled safely after 24hrs of burn-in.

For any new tube amps or electronic equipment which I purchase, I also make it a point to leave it on for 24 hrs straight. In the electronics manufacturing industry, if any electronics equipment can survive a 24hrs burn-in, it is very likely to be able to last the whole of its guranteed period assuming normal usage.

BTW, please do not touch the tubes when your unit is still on.
Vacuum tubes are the most vulnerable at this point and any tapping or harsh movement might damage them.

[DaveC113]

My tube preamp (Anthem Pre 1) recently malfunctioned and the power trafo started smoking. I assume the fuse would have eventually blown, but I pulled the plug as it was filling my living room with the smell of burning electronics.

While my system was down I checked my power amp, a DIY EL34 SET amp. It has been used for 5 years + everyday and has been left on overnight accidentally a dozen times or more. One of the power tube's cathode caps (1500uF electrolytic) went out and the cathode resistor ran hot and burned the PCB a bit.

One strategy for a preamp is to run the filaments 24/7 and switch the HV trafo. I'm installing switches for each trafo on the tube preamp I'm building. My old pre ran the filaments whenever the unit was plugged in.

Personally, I won't keep high voltage running in a tube amp while I'm not around.   

[FullRangeMan]

DaveC113:
Sorry for your prob. Today the tube builders no more use two power on switches(it cost 0,25 dollar in China) to Filaments and to B+, only Atma-Sphere use these two switches.
They prefer use a more expensive short 30 seconds timer or nothing, thus creating the bad flash on the tubes at the power on, as in this video(around 7 seconds time) it is a dirty, poor design solution.
In the tube era 2 switches was more popular, it were labeled ''power'' and ''Operate''.
http://www.youtube.com/watch?v=NPc8JN9mbDE&feature=related

[Quiet Earth]

DaveC,
1500uF sounds kinda large for a cathode cap. You said a DIY amp so I suppose anything goes. Maybe that cap was under-rated in voltage or over-achieving in capacitance? Or maybe it just failed and that accounts for a small percentage of failures.

The Anthem story is the second transformer melt down story I have read about here on AC. I don't understand why a fuse didn't go out in either circumstance. Sometimes we buy things that are not made correctly . . . that's about all I can think of. I hope this is the exception and not the rule.

With preamp tubes we are not really talking about that high of voltages, I'm thinking around 50v max for the plate, if even that. (I guess that seems like high voltage if you are coming from a solid state world of 12 to 18 volts). Power amp tubes can run very high in voltage though, they run hotter and live shorter lives, so yeah, turn them off when you go to bed.

[Quiet Earth]

Oh yeah, and I'm not a big fan of running heaters 24/7 with cold plates any more like I used to do with my counterpoint preamp. I don't think there is an advantage over just running the tube full on. Just my personal observation, not scientific.

My AudioValve phono stage has this feature and I don't use it. (I do use it to gently turn on the phono from a cold start, but I don't leave it in heater only mode.)

[doug s.]

Many people leave tube preamps on 24 x 7, just to give you an idea how much you should not worry about it.

yup, i only turn my tube preamp off when i am gonna be away from the house for a couple days or more...  but, someone is usually around during the day, and i am presently living in a one room studio apartment, so the stereo stays on when we go to bed.  so, the system sees a lot of use.  when i move to a more normal abode, the system will get turned on in the morning, get turned off at bed time, and stay on from friday morning to sunday night...

doug s.