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Turning off tube preamp first sends solid state amp into protection?

I have been experimenting with using a vintage Luxman CL40 valve preamp as a separate preamp stage for my L-509X integrated. Because I leave the solid state amp on 24/7, I accidentally turned off the preamp while the 509X was still in Separate mode. The integrated immediately went into protection mode with the power light blinking. I powered it down into standby mode, then brought it back up and it remained in protection mode. It wasn't until I unplugged the 509X and plugged it back in that everything was cool. 

Did I do any potential damage here? What it it happens again? It's pretty easy to accidentally turn off the preamp when I'm leaving the 509X on all the time.
jsqt

Showing 2 responses by harrylavo

harrylavo's avatar
harrylavo
346 posts
 
One of the all time truths from the "hi-fi" stage - start turning off at the far end of the chain.  Always power amp first, preamp second, originating component third.  And reverse when powering on.  Especially with tube gear.

You eliminate dc offsets, and you eliminate instability.  Modern equipment sometimes uses slow-warm-up components and other circuit tricks, but your Luxman certainly would not have those.

If you had damaged your amp, it would stay in protected mode once you shut down and restarted completely from scratch.  It didn't, so you are safe.

harrylavo's avatar
harrylavo
346 posts
 
n80 - That gear should give you good sound, and your sequence is correct.  But you should not have to turn off the amp once you've put it in standby.  Standby cuts power consumption to only a few watts, but keeps the capacitors formed.  It may lengthen the problem-free life of the amp.
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