Question for anyone who knows these amps. I opened the top and turned the power on to see what kind of glow I get and how long it takes to warm up. It takes about 15 seconds to get a warm glow out of the 12AX7's but my main concern is on the initial power up. The one tube that's not an AX7 gets extremely bright as soon as I power up, then goes dim and warms up with the rest of them. It's the one second from the top. Is this common? I'm kind of new at the electrical side of things and am curious.