What is the correct sequence to power On/Off tube gear?

ymarko

Super Member
I’m new to tubes. I know that Tube amp should be never powered On without load.

I’ve heard that it should be a certain sequence / procedure in powering on Tube pre-amp and Tube amp, as well as shutting them down.
Also some waiting period before the listening session, letting tubes worm-up, etc.

Could somebody explain please?
 
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Far as I know, it's generally same as any system...

On: pre amp then power amp
Off: power amp then pre amp.

I wait a minute or two before starting the music, which is about three or four times longer than it takes before any sound will come out anyway.
 
Tube gear usually doesn't suffer from the nasty turn on/turn off pops that solid state gear normally suffers from when using separates.

If you are using a separate tube preamp and tube amplifier, you would normally have the tube amps power cord plugged into the preamps switched power receptacle so when you turn on the preamp, the power amp comes on.

Since tube gear has to warm up (usually about 30 seconds), it doesn't suffer from the nasty pops of solid state gear that is powered up or down improperly.

Now if your tube power amp stays powered up even when the preamp is turned off, then yeah, you will get the turn off pop.

With solid state gear it is usually everything else on first, power amp on last, and just the opposite when shutting down.
 
Power amp on last, off first if I'm running the tube amp. If I'm running an SS amp, the tube preamp is on and off first. The preamp warms up and shuts down quicker than the tube amp does. Obviously its slower than an SS amp though.
 
Turn on before listening; turn off after listening :-)

:lmao: :thmbsp:


The easy way to remember the recommended sequence is simply to think that gear being turned on or off can send out a "pop" at the time you switch it on or off. You do not want that "pop" going out through your speakers, as it might damage them.

Therefore, when turning things on you turn the preamp on BEFORE the power amp. That way, if it pops, the pop will go to the still-turned-off power amp, and not make it to the speaker. A pop cannot damage gear that has not been turned on, unless it is something like a lightning-strike POP! Conversely, when turning gear off, turning the power amp off FIRST prevents any pops from the preamp (or earlier gear in the chain) from going through your speakers.

Of course, if your power amp produces the pop, you're screwed no matter what, so make sure that unit is kept well-maintained. :D


As for tube warm-up, it won't take long to produce sound. My preamps and power amps have two modes: "stand-by" and "on". to REALLY switch them off, you have to unplug them! The indicator LED light switches color 70 seconds after you turn a unit "on", and it will play from then. However, you can hear improvements in the sound over the first 30-60 minutes, as the tubes heat up fully and more-or-less stabilize. I think that is true for almost all tube gear. There are showrooms here in Hong Kong that will refuse to demo their gear for you, unless you give them advance warning, because they know that it takes that long for their systems to fully heat up and sound their best.

I rarely wait an hour before I start listening, but I do realize that what I hear immediately after start-up is not the best sound I can hear, so if I think of it far enough ahead of time and I'm in the mood for some "serious" listening, sometimes I'll let the system sit on for a while and go eat or do something else for a little while, before I start the "serious" listening.

Fortunately, the optimal listening temp is reached much faster if the gear has been sitting in "standby mode" instead of fully off - within perhaps 5-10 minutes, so if I have multiple listening sessions planned within a day, or am only stopping listening or a little while to focus on something else, I may just leave the gear sitting that way.
 
Far as I know, it's generally same as any system...

On: pre amp then power amp
Off: power amp then pre amp.

I wait a minute or two before starting the music, which is about three or four times longer than it takes before any sound will come out anyway.

Correct.

I might add, if you guys are getting "pops" from power switches, just stick a .01 x 1kv ceramic cap across the contacts.
 
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Correct.

I might add, if you guys are getting "pops" from power switches, just stick a .01 x 1kv ceramic cap across the contacts.

This keeps the switch from burning itself up. Its a good idea even if you aren't getting pops.
 
The reason for the On/Off sequence might be helpfully so folks understand why.

When turning on a preamp that employs an output coupling cap as the preamp comes up from a cold state the dc voltages are unstable and until they stabalize the output coupling cap will leak dc voltage to the amplifier. So for the on cycle it's preamp on then amp on.

The off cycle is the reverse..when you shut your preamp off it will again leak dc to the amplifier for the same reason. So amp off then preamp off.

In the grand scheme of things chances are very slim that any harm is going to crop up regardless of how you turn the gear off but technically the above is the how and why.
 
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