Can a NOS pair of 6SN7 blow a woofer?

[greg7]

A friend of mine just installed a pair of NOS 6SN7 for the first time in his preamp and one of the woofers on his speakers immediately blew once he started playing music. Is that possible and, if so, how? Odd coincidence but maybe it was something else. The only thing I can think of is a huge amount of DC was somehow present in/of/through one of the 6SN7

 

[JonSnell Electronic]

DC 'through' a valve is normal. I would suggest maybe there is no AC coupling from the pre amp to the main amp perhaps.
A 6SN7 cannot, on its own, blow a bass speaker.

 

[pcan]

I once had a nice 6SN7 NOS Tung-Sol on my preamp that suddently became higly microphonic, but I didn't noticed it immediately. I accidentally tapped it while the volume control was near the maximum; a very loud "bang" sound from the speaker scared me. My amplifier is low power and the speaker was left undamaged. With a more powerful amplifier, some damage to the woofer driver may have been a possibility.

 

[Burnedfingers]

Why not send all of your 6sn7's to me. I will guard them to make sure they don't plug themselves into an empty tube socket. By doing this you will provide me with a life time supply of 6SN7's. Don't stop there.. I will also take 5692's or anything else that is free.

 

[dhaen]

You haven't mentioned the amplifier model or topology.
I once repaired an OTL amp with 6 x PL509s in each output stage. There was DC coupling from the driver valve, so in that case it is possible.
However in most topologies it will not happen since they are transformer coupled.