Use, 6SL7 is even more microphonic than 6SN7. But not as irreplaceable if ultimate sonics are the goal. Gain notwithstanding.
How to isolate turntable from footstep shake or vibration
Even while the Oracle turnable that I use has a built-in springs suspension by design there is a low or even sub-low frequency boom every time someone walks in a room. This becomes really bad with the subwoofer’s volume set high as the low frequency footsteps make straight to subwoofer where they are amplified shaking everything around. It seems the cartridge is picking up the footsteps very efficiently as even a lightest foot down becomes audioable. What can be done to attempt to isolate the turntable from the low frequency vibrations? Interesting, that the lower the volume of the subwoofer, the less the footstep shake is evident and with the subwoofer turned off it is a barely a problem at all.
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I wasn't all that bothered by footfalls in my former house although it had suspended wood floors, and if you jumped by the turntable it wasn't good...my new place is suspended but not under my listening area...that's a slab...and man, nice...you could operate a jack hammer in that room and the table wouldn't notice except for the dust...still...also, the myth of coddling tubes because they're "all" somewhat microphonic is silly...they're not (some are...get rid of those). I've used and still use tube bass amps as well as many tube combo (if you don't know "combo" it means the amp is in the speaker box) guitar amps that make that point over many years, and my current tube pre and power amp also are seemingly immune to microphonic paranoia. Fear not. |
@wolf_garcia , I though guitar amps were chosen based on the distortion they produced. How can you tell if a tube is microphonic or not if the amp is distorting it's backside off? Tube guitar amps are desirable because of the distortion they produce! (at least that is how I understand it) Interesting point though. Same for automobile systems although tubes are long gone in those. @lewm, My understanding is that Upscale Audio and RAM labs do grade their tubes on microphonics and two other parameters. And, what do those tube rubber band damper rings that ARC supplies do? They obviously dampen the glass. Does that decrease microphonics? Are they the reason I can tap on the tubes and not hear it through the system? I was tapping on the tubes because one of them went bad and I was trying to figure out which one it was. Tapping did not help. @atmasphere , I have been using a Sota since 1981 and have had it on everything you can think of playing through ESLs. I have not found anything to be as important as using a dust cover during play attenuating airborne vibration by as much as 20 dB (not sure how accurate the meter was). Like protective earmuffs for your cartridge. And, everyone thinks this is poison (except Mark Dohmann). I guess like guitar amps everyone likes listening to distortion? With subtle differences I guess people prefer sticking with mythology than really listening? Boggles the mind. |
FWIW and noting that this thread has taken a side route, here are just two documented sources for tube microphonics; -Proceedings of the Institute of Radio Engineers, Volume 17, Number 9 September, 1929, MICROPHONIC IMPROVEMENT IN VACUUM TUBES IRE-1929-09.pdf (worldradiohistory.com). -Getting the most out of VACUUM TUBES by Robert B. Tomer, 1960, Getting the Most out of Vacuum Tubes (worldradiohistory.com) This site has THE HISTORY RADIO and BROADCAST HISTORY library with thousands of books and magazines (worldradiohistory.com) and this site is an amazing resource. Its takes some time to figure out how to use the many search features, but once you do, it can answer many of the questions or technically guide conversations associated with this technology that is proving to still be relevant as it enters its 2nd century. |
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