Soundthought Posted May 24, 2003 Share Posted May 24, 2003 Hello all, I'm looking for some insight on a curiously old fix-it technique. Recently, I was reading an article about regenerating tubes that test low. It was pretty straight forward. From what it said, you're suppose to put them in the oven on a cookie sheet and bake them for a specified period of time at a particular temperature. Apparently, it claims to be able to bring new life to old tubes. ????? Has anyone else heard of this? Regards, John Quote Link to comment Share on other sites More sharing options...
marksdad Posted May 24, 2003 Share Posted May 24, 2003 i dont remember the particulars, but when i used to fix electronics, i remember the old timers doing this, sorry i just never asked Quote Link to comment Share on other sites More sharing options...
Jim Cornell Posted May 24, 2003 Share Posted May 24, 2003 John i see you finally flipped LOL Wont this bake off the base of the tube? Im afraid to ask you whats new LOL Jim Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 24, 2003 Share Posted May 24, 2003 Actually this was common practice back in the Day my Dad has told me many a times that it really works. At one time when my Grandpa could not afford new tubes for the family radio when a show would be coming on he would bake the tubes before they were all going to sit down and listen !! It works but just temporary ! Weak tubes will test stronger after there warmed up in my tester all the time ! The tube bases are designed to take major heat by the way. Grab one after your amp has been on for a few hours Craig Quote Link to comment Share on other sites More sharing options...
lynnm Posted May 24, 2003 Share Posted May 24, 2003 Baking tubers smell marvelous !! AKA - Baking Vacuum tubes at high temperatures might well result in a temporary revitalisation as this could cause the innards to shed any oxidisation artifacts from the cathode and the plate. As far as I am aware nobody has ever found a way to create and maintain a perfect vacuum during the manufacture of vacuum tubes ( although the manufacturers have been able to come damned close to achieving that goal even in the early days of VT production ! ) but a little oxidation is inevitable. That said by the time a cathode has become oxidised to the point that said oxisidation can materially effect the transfer of free electrons from cathode to the plate and/or the plate has become oxidised to the extent that its ability to recieve electrons is seriously compromised it is fair to say that the tube has had its day. Baking a tube is the electronic equivalent of giving CPR to a 98 year old Alcholic. It may give a little more life but the end will always be in sight ! BTW If that 98 year old Alcholic should survive that crisis and be cognitivly intact enough to continue enjoying life - I say do everything possible to support him/her. Quote Link to comment Share on other sites More sharing options...
Soundthought Posted May 24, 2003 Author Share Posted May 24, 2003 Thanks to everyone for the replies. This concept of baking tubes makes alot more sense now. At first, I was like... what?.... But now, I can see the inherant benefits. Even if it is only a temporary fix, it's always nice to know the old school tricks of the trade. I was reading one of my old 1960s Popular Electronics when I had come across this concept. The article just stated what to do and how to do it, but didn't go into why it works. I will try to find that article again and reprint it verbatim for all to see. It might take me a day to find it, though. I just got a new box of these old rags and had spent an evening just reading them all. Now, if I could only remember which edition it was in. LOL For me, like PWK used to say; "I have a photographic memory, but sometimes it doesn't develop." I am intrested to know if it would work with an EL-34? I've got a quad of Telefunken with two of them testing way low. It would be pretty cool if I could get some use out of them. Regards, John. P.S. Jim, what's new you ask? Don't ask! LOL You don't want to know..... Quote Link to comment Share on other sites More sharing options...
Deang Posted May 24, 2003 Share Posted May 24, 2003 I used to boil my guitar strings when I didn't have money for new ones. You might try that instead. Quote Link to comment Share on other sites More sharing options...
Soundthought Posted May 24, 2003 Author Share Posted May 24, 2003 Hmmmmm. Dean... Dean... Dean. Don't think so, my friend. I already took them apart and cleaned the silver crap outta the inside. They really shine now. I don't see how boiling them will get them any cleaner. whoops......ha ha ha ha J/K. What's this about boiling guitar strings? I'll admit, after a session, I'll take what's left of my good strings and clean them for later use, but never heard of boiling them. Ernie Ball soup, anyone? Regards, John Quote Link to comment Share on other sites More sharing options...
Deang Posted May 25, 2003 Share Posted May 25, 2003 It kind of works like baking the tubes I think. Boiling the strings gets all of the crap off the strings and actually shrinks them down back to where they were when they were new. It only lasts about a week or so -- but works. Quote Link to comment Share on other sites More sharing options...
Soundthought Posted May 25, 2003 Author Share Posted May 25, 2003 I had never thought of it that way. Thanks Dean, i'll give it a shot. BTW. How long should I boil them? Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 25, 2003 Share Posted May 25, 2003 ---------------- On 5/24/2003 9:59:12 PM Audioreality wrote: Thanks to everyone for the replies. This concept of baking tubes makes alot more sense now. At first, I was like... what?.... But now, I can see the inherant benefits. ---------------- Glad you do. This is what I see--the getter in the tube attempts to absorb residual gases that would otherwise destroy the filament. Getters are either *flash* getters (the silver spot on the tube inside diameter), ribbon getters, ring getters or simple *painted* getters residing on a filament/plate post. Baking a pinched-off tube drives the getter to release the gassy *crap* that it captured giving the filament a gas *dose* of sh*t that will do nothing but reduce it's life. Quote Link to comment Share on other sites More sharing options...
Deang Posted May 25, 2003 Share Posted May 25, 2003 About 15 minutes -- then wipe them down and make sure they are completely dry. uh -- this is usually for dirt poor teenagers who have to wait for their next allowance before they can buy strings again. Quote Link to comment Share on other sites More sharing options...
Soundthought Posted May 25, 2003 Author Share Posted May 25, 2003 John - reduction of life? I guess that would be alright, if we're talking about utilizing this procedure for tubes that already test below operating parameters. Dean - Well, it's all how you look at it. No doubt that a set of your basic GHS Boomers is cheap, but I only keep and clean my better, more expensive strings for practice/back up purposes. Gotta get my moneys worth, eh? When it comes time for a session or gig, though, I always put on a fresh set. Regards John. Quote Link to comment Share on other sites More sharing options...
Griffinator Posted May 26, 2003 Share Posted May 26, 2003 ---------------- On 5/25/2003 9:08:07 AM Audioreality wrote: Dean - Well, it's all how you look at it. No doubt that a set of your basic GHS Boomers is cheap, but I only keep and clean my better, more expensive strings for practice/back up purposes. Gotta get my moneys worth, eh? When it comes time for a session or gig, though, I always put on a fresh set. Regards John. ---------------- LOL! Actually, I am one of several bassists I know that boil our strings periodically to keep them fresh and lively. When you're dealing with $55 for a good 5-string set, it's not only economical, it's a no-brainer! Quote Link to comment Share on other sites More sharing options...
Marvel Posted May 26, 2003 Share Posted May 26, 2003 But putting on new strings is sooo good. That small window between the too much zing and the going dead part! If you have a very good acoustic, you are way into the dead string part before you realize it. Then you meet people who say they have had the same strings on for five years. "Oh, you mean I should change them?" Basses are a different matter entirely. Marvel Quote Link to comment Share on other sites More sharing options...
Tony Boone Posted May 26, 2003 Share Posted May 26, 2003 ---------------- On 5/24/2003 4:30:59 PM Audioreality wrote: ... put them in the oven on a cookie sheet and bake them ... ---------------- I don't know about the tubes but every time I see this thread subject line I want some choc chip cookies. Especially late at night. Tony Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 26, 2003 Share Posted May 26, 2003 Well just to let you all know I tried the Oven baking and then retested a tube yesterday ! I baked it at 350 for a few hours before the baking it tested 7500 and the needle would drop like a rock after peak which means low life ot dyeing ! I tested after the bake 8750 with slightly more stable reading but dropping slowly. Put it in the amp and biased them up ran the tubes for about 2 hours pulled the weak one out and it was 7000 and dropping faster then before the Bake job ! So as I said before its completely temperary and not worth the effort ! To bad it would be great if it saved this one weak Tungsol 6550 !! But then no one would ever need tube now would they Craig Quote Link to comment Share on other sites More sharing options...
Soundthought Posted May 26, 2003 Author Share Posted May 26, 2003 Craig, That sounds like the right formula for the tube bake procedure. I haven't had a chance to look through the magazines for the article about it. I'll post it as soon as I find it. It's nice to know that it will work in a pinch, but it sounds like it ultimately brings forth the demise of the tube(s). Thanks for doing the experiment. I would try, but my oven has been broke for like 6 months. BTW, Craig, I am still coming out to rebuild my ST-70 soon. You've been warned. LOL Regards, John Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 26, 2003 Share Posted May 26, 2003 What ST-70 Quote Link to comment Share on other sites More sharing options...
Soundthought Posted May 26, 2003 Author Share Posted May 26, 2003 Heh heh. Everybody funny. Now you funny too. LOL Let me rephrase what I said. I'm finally going to haul my procrastinating a$$ out there and learn how to fix that thing up right. That is, of course, if there is still something for me to fix. Quote Link to comment Share on other sites More sharing options...
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