What is Wrong?

I just received tubes installed them in Gain stage of my Schiit Freya+, turned on my Cherry STM  amp, then freya,then Audiolab CDT, Schiit Bifrost. I do not remember if I started CD transport, but I detected hum, out of 1 speaker also it had low volume. Switched tubes, gain to buffer, put back original configuration, same thing. Turning every thing of and switched speakers on my amp. Now hum and low volume out of other speaker. Weird any thoughts? Why after installing new tubes?