1 Journeyman 1 week ago For all you octal preamp folks, a nice old 1961 Ampeg M12 Mercury came my way recently and I found that most of my old stock 6SL7 tubes were microphonic; the worst being the stubby GEs. So, I bought three of the new JJs at about half the price of the new Tung Sols, and they are great. Just holding them one has a sense that these are solid, quality made tubes. The best part is that they ARE solid, with no rattles, and are dead quiet when running in the amp.The other 6SL7 that seems fine is the Russian 6H9C; exactly the same tube, and can sometimes be found labelled as 6SL7 and sold by Sovtek. I honestly can't hear any difference in tone between the JJ, 6H9C, GE, and Sylvania tubes, only performance wise, the JJ and Russian tube are perfect.I've noticed the prices on the 6SL7 going up over the past couple of years, due I'm told, to the audiophile folks discovering how great they sound and creating demand; the Russian 6H9C is a deal for the time being.