As the title says, the Hartke HA5500s tube preamp has no output signal. I was playing and it was working just dandy, then when i adjusted it later on i heard it all of a sudden had no output signal. Its not really a big deal as i prefer the SS preamp, but i did enjoy mixing the SS with the Tube (while it lasted). This amp isnt new, i started using it today but i bought it off a guy who owned it for 5 years. If anyone has any idea what the problem might be help is much appreciated.