Hey tube dudes, I read the sticky recommending that you bake your old tube amp. Is this with the tubes still in? Also, the variac. Is this used for preamps and tuners as well as power amps? Is the variac just an initial process, or one that is used every time you listen? Thanks, I'm still cruising with training wheels at this point, so thank you for bearing with me.
Amp baking.
- Thread starter dualhead
- Start date
Register to hide this ad
NYListens
CBGB & OMFUG
I can't comment on the baking, other than to say that I wouldn't have the tubes in it, as there is no reason to. I use a variac to soft start any old tube equipment I work on.
No tubes necessary....
bake until well done, at less than 85 C. Variac for initial ramp up to reform caps, etc as per sticky. Works like a charm....:thmbsp:
bake until well done, at less than 85 C. Variac for initial ramp up to reform caps, etc as per sticky. Works like a charm....:thmbsp:
relaximus
Consoles 'Я' Us
As AA says, this works well. I have done this and can't really comment as to whether it makes a difference, but I have certainly had no ill effects. The reasoning behind it, to my mind, seems sound. Certainly, all tubes must be removed before hand. I used 140 degrees (F) for my bake at around 2 hours. Whether it actually re-flowed the goop in the caps, I couldn't tell ya (had it re-capped after the fact) and you'll want to replace all the electrolytes anyhoo. Did it percolate any moisture out of the x-formers? Dunno. Did it hurt? Nope. Did it help? Again, dunno. But again, the reasoning (for me) is solid. My advice would be to give it a shot. The end result is going to be hard to judge subjectively. Chances are if you've got the chassis out, you're going to be doing additional work to it anyhow. A strict A-B comparison is likely not in the cards. And yes, always bring it up softly (with a variac or the poor man's variation) when done.
Dave
I've herd of baking old carbon comp resistors to see if there value goes out of wack. Never done a whole amp before. As for trying to get the goop inside of a 30+ year old electrolytic to re flow I wouldn't recommend it. I have had can type caps form up fine and then after a few power ups they start leaking and trust me you don't want this especially if the amp has boards in it, not to mention it stinks.
Just put new caps in it, match the uf/mf values best you can but make sure the voltage values are at or above what your replacing.
Just put new caps in it, match the uf/mf values best you can but make sure the voltage values are at or above what your replacing.
soundmotor
super modified
Mmmmmmmmmm, the smell of mold, cellars, insect carcasses, mouse ****, & eons old tobacco smoke filling my home. Better than apple pie! OK, I know all of you clean the loose stuff out before baking but the thought of putting any piece of old gear into a spot used often for food preparation is not happening. But y'all go right on ahead with that.
:thmbsp:
:thmbsp:
well, ideally if you do this often you'll have an old oven out in the garage or something to cook things in. Its also handy for powdercoating small items.
I don't bake my stuff either, I also don't put it in the dishwasher or replace all the caps before I fire it up. I usually bulk replace coupling caps and "death" caps and I try to replace the electrolytics if I have them on hand, but I've got plenty of stuff chugging away on 50+ year old filter caps. I soft start on the variac but thats about it. Once it powers up a couple of times, it gets plugged into the wall and it sinks or swims from that point.
I don't bake my stuff either, I also don't put it in the dishwasher or replace all the caps before I fire it up. I usually bulk replace coupling caps and "death" caps and I try to replace the electrolytics if I have them on hand, but I've got plenty of stuff chugging away on 50+ year old filter caps. I soft start on the variac but thats about it. Once it powers up a couple of times, it gets plugged into the wall and it sinks or swims from that point.
So just the first couple times on the variac. OK. Now, what is the poor man's version (as I am definitely that man)? If I have already started and used the Pre for about thirty minutes have a pasted the point where the baking would help? Thanks for the replies.
The biggest advantage of this, IME, would seem to be the possibility of driving any moisture out of the transformers. That alone, could be a life-saver, if the amp has been stored in a damp environment.
As mentioned, I'd think 140 degrees would be plenty... warm enough to drive off moisture, but not high enough temperature to damage any plastic parts...
Regards,
Gordon.
As mentioned, I'd think 140 degrees would be plenty... warm enough to drive off moisture, but not high enough temperature to damage any plastic parts...
Regards,
Gordon.
well if it fired up and passed signal and its not humming like crazy I would say you have a working preamp and have no need or reason to pop it in the oven. Just what preamp are we talking about here ?
is this the tape recording pre that uses the eye tubes for level meters for each channel or is it the later one with analong meters ?
relaximus
Consoles 'Я' Us
Okay, if you don't believe me than you had better believe in Gordon! :ntwrthy:
As I mentioned, re-flowing the caps is iffy and they should be replaced anyhow. But the other benefits mentioned, might just save your amp's bacon! A transformer saved is one less walk down the path of potential unobtainium.
Dave
Yep. No real need to remove the tubes. They're made to handle higher temps than these...
Now... just to put in the obligatory "there's always a bigger idiot" warning... PLEASE, nobody try doing this with a microwave oven!
Regards,
Gordon.
cademan
Lunatic Member
Must be where you live! Here in washington state, I measure 120 volts AC exactly. One of my tube amps has the sticker on it that says: 117 VAC only!
I doubt a 3 volt difference is going to create much of a problem.
So they don't get accidentally smashed while shuffling the thing into the oven? Maybe the sockets expand a little as everything heats up, and a tube falls out of the socket?