Expanding questions about tubes in a preamp
Gents, how the hell does adding damping rings change the sound of a tube.Get two 6550’s one GE NOS green label and one Chinese junker, flick each and listen to the Chinese one ring like crystal and the GE just go thud. That’s the reason. It’s all about airborne feed back from your speakers, if your tube pre and power amps were in another room there’d be far less concern. This is why the flick test in my first post will give you a fighting chance against micro-phonics in tubes. Cheers George |
insearchofprat OP First weed out any mircophonic tubes. Do this by turning up the volume to where it sits normally for loud listening, get someone to gently flick each tube with his finger nail while you listen at the speakers for the bad ones. A quiet "bonk" is ok, loud or a tinkle behind the bonk (tinkle can be very loose stretched heater filaments) or sometimes when real bad you'll get run away feedback, quickly turn down the volume.. Once you have a batch of good non microphonic tubes in, then these cheap red "O" rings the thick ones, two per tube one high, one low not too tight. I have seen power tubes get a dent around them when they were too tight. (don’t bother with expensive audiofool tube dampers). https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313.TR5.TRC2.A0.H0.Xsilicone+%22o%22+rings.TRS0&_nkw=silicone+%22o%22+rings&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=Red+silicone+%22o%22+rings Cheers George |
