Tubes Asylum Questions about tubes and gear that glows. FAQ

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ Tubes Asylum ]

---

[ Alert Moderator ] [ Edit ] [ Delete ]

---

Re: Help this pathetic newbie to tubes : )

69.179.106.5

Posted by Jimmy on August 5, 2006 at 14:45:52

In Reply to: Help this pathetic newbie to tubes : ) posted by McGruder on August 5, 2006 at 13:09:47:

#1) Nobody wants to talk about NOS being depleted, but same persons are squirreling away those tubes in a quick manner including myself. I keep nothing less than a very conservative estimated 40000 hours of NOS tube spares for my amps. Perhaps I should keep 80K hours worth of spares. Supply & demand like anything else. High demand & minimal supply means higher prices everytime.

#2) Power output tubes have gained leaps & bounds in the last few years. Even the Sovtek 12AX7LPS is a very good tube in some circuits edging out some Telefunken smooth plate & short plate Mullards in a Dynaco SCA-35. So, I suspect new manufacture will get even better in the future with common types of tubes.

#3) Sure! Who would want to burn tubes 24 hours a day & listen to the tubes a few hours. Nuts to my thinking. Soft start the tubes if cold filament start-up is a concern.

Life of most preamp tubes operating within recommended manufactures ratings are at least 5000 hours & 10000 is not unheard of either. Older octal seem to have an advantage over miniature types, but lots of factors effects tube life. Amperex PQ were stated by manufacture to be 10000 hour tubes & Telefunken can last longer.

Some audiophiles report preamp tubes with 3K hours start to lose some high-end sparkle (if you will). It really depends upon the circuit & how hard the tubes are 'low biased' (operated) in a circuit.

Power tubes usually become weak faster than preamp tubes. It just depends upon how much filament power is available in the design & how hard the tubes are operated in the circuit. But, 3000-5000 hours should be the life expectancy for oxide filament tubes. It is dependent upon filament power & operating temperature. A TV sweep tube with a massive 6.3 volt @ 2.5 amp filament operated in our parents TV everyday for 8 to 10 years. Audio tubes usually have 40-65% of that much filament reserve. Some triode thoriated tungsten filament power tubes can last 20000 hours or longer.

#4) Well known tube dealers back up their products. Look at the supporters on the AA home page. For example, Jim McShane would leave the tube business before even thinking the customer was not pleased with a great product including a carefully tested & packaged product. thse guys are hobbiests first supporting hobbiests. These guys may ask a few more dollars for their time involved in the transaction, so do not shop the cheapest price available just anywhere.

#5) I have no idea why the microphonics rating, but I stay away from microphonic tubes in home entertainment amps.

#6) I have no background with the BC3000.

This post is made possible by the generous support of people like you and our sponsors:

Sonic Craft

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---