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Did I blow my tube amp?

So here's the story: I recently received my tube amp and replaced the power tubes. So naturally, I wanted to bias them to make sure they work properly. I've never done any biasing before and checked some youtube videos on biasing. One of the youtube video had a Manley Stingray connected to power, no input signal, and NO speakers connected. I did the same. After the biasing is done, I connected the speakers and input signal, but for some reason so sound came out.

So the question is: did I blow my output transformer? Simply by not connecting the speakers while biasing or just having the amp on for a short while? From what I have read, it should be ok to have no speakers connected as long as there's no input signal.

I had another tube amp before this, and turned it on one time without speakers connected and it worked flawlessly after.

Could you guys shed some knowledge or personal experience on this topic?
vu001
jea48
4,419 posts
 
One of the youtube video had a Manley Stingray connected to power, no input signal, and NO speakers connected.
Not sure why the guy did that......
Manual does not say to do it that way.

I did the same. After the biasing is done, I connected the speakers and input signal, but for some reason so sound came out.

So the question is: did I blow my output transformer?
I don't think so.... Not from just biasing.

But.....
Reading from the manual,

Connecting your Stingray.
(1) "You MUST have speakers or (load box) properly connected to the speaker terminals before power is turned on ........."

Reading the manual it says to make sure when connecting the speaker wires to the amp to make sure the ends of the wires do not come in contact with the case of the output transformers.... (Dumb way to build something)
So make sure the speaker wires are not contacting the output transformers.

Double check the input jacks. Make sure interconnects are seated properly.

Post back your results.

You didn't post the model year.....

http://manleylabs.com/PDF/HIFI_Manuals/Hi-Fi/Stingraymanual32001.pdf

http://manleylabs.com/PDF/HIFI_Manuals/Hi-Fi/Stingraymanual32001.pdf
.
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ncarv
983 posts
 
Did you check the B+ fuse?

When I changed the power tubes in my older VTL/Manley designed tube amps, I had the whole system connected and I changed one tube at a time, turning the amp off each time I replaced a tube and turning the amp on to bias the new tube. I also made sure after changing each tube that the other tubes were biased correctly, as changing one affected the bias on the others.
dilly
113 posts
 
I am no expert in the matter but my Cary amps are biased with all connections removed as recommended by the manufacturer. Best would be to check with manuf. Or trouble shoot with the user manual.
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