2. amps-preamps
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tubed preamp off and ss amp left on?

Why can't I leave my my ss amp turned on with the tubed preamp turned off? Loud hum occurs through speakers with this condition. When I had a ss preamp I could leave the amp powered all the time with the pre off. I would leave all powered up but concerned about the preamp tubes wearing prematurely. Is it a reasonable conclusion that I could leave everything powered on all the time and just change the tubes once per year?
twc
jea48
4,660 posts
 

If the preamp has a mute feature, switch the preamp to mute before you shut it down. See if that helps.

Otherwise you best turn off the power amp first then shut down the preamp.
warrenh's avatar
warrenh
2,299 posts
 
I can't figure out the possible reason for your hum, but be patient. There will be a 'goner that will set you free. Fortunately (shortens my waiting time for optimum sound) my SET rig has a standby/idle feature on both the amp and the pre. The amp is good to go after the 845s have 30 minutes on them and the pre just has to wait for the amp/845s to catch up. Idle would be a nice feature on all tube pre amps and amps.
arni
313 posts
 
Hm, some say that turning tubepre off and on is what kills the tubes prematurely.... preamps differ significantly in regards to how long their tubes last, where some reportedly should be turned off, others not. Knowing what your preamp is might help with answers. My tubes have been on for a year, and going strong (ECC 82).
pescolar
128 posts
 
Set your volume to maximum low and turn off your amp first and wait for a minute or two and then turn off your pre-amp.Result will be dead quiet.
warrenh's avatar
warrenh
2,299 posts
 
Funny, I had posted a similar question a few weeks ago, having come back to seperates after over 20 years. If the volume is down on the preamp, should it matter which you shut off first? Nowhere in my amp or preamp manual does it say to be certain to shut off first or last. I think volume down on the pre is the answer?
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