2. amps-preamps
  3. 139933-120167

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.
128x128jsqt
jsqt's avatar
jsqt OP
117 posts
 
I'm not sure, is that supposed to be happening (passing DC to amp)?

I just have my DAC going into the RCA input of the preamp and then the output of the preamp going into the HT bypass (Main In) of the 509X. There shouldn't be any DC current moving between the two should there?
Ag insider logo xs@2x
tonykay
1,302 posts
 
To avoid the "pop" I had become familiar with, I have started to turn on the solid state power amp well before I turn on my tube preamp. Is it the right sequence? Really don't know but I don't get that pop anymore.
wolf_garcia
6,713 posts
 
Always turn the preamp on first and off last, although with many modern systems it might not matter much...but that's been the conventional wisdom for a while. 
harrylavo's avatar
Ag insider logo xs@2x
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.

jsqt's avatar
jsqt OP
117 posts
 
Thanks this is all good to know.

I was aware of the power up/power down sequence but since adding the L509X I leave the power amp on 24/7.

By adding the vintage valve pre, it sounds like I'll be having to power down the solid state integrated instead of leaving it on full time.

I'm only using the valve pre with the 509X at lower volumes, as it really adds to the sound of vocals at lower volumes.
More to discover