Manley JUMBO SHRIMP - Manual (Page 12)

More silly vacuum tube questions...
FAQ #16f. Should I turn off my gear between uses?
While power cycling is a factor for ultimate tube life, there also is a fixed number of electrons that can ultimately
jump off the cathode. In general we do recommend if you aren’t using the gear for more than a few hours you
should power it down. Do you leave the lights on in your house when you are away?
FAQ #16g. But it sounds different when you first turn it back on. What is the warm-up time for this gear?
I generally recommend 45 minutes warm-up time for everything to reach operating temperatures and sound like it’s
supposed to.
FAQ #16h. What about break-in time for new gear?
We burn in the gear for a couple of days before it is shipped out. Folks report that after about a week of break-in
that it sounds better. Some of the more fussy people of course report that full break-in takes much longer....
FAQ #16i. How do I know a tube is broken?
All the vacuum has leaked out.
FAQ #16i.i After the vacuum leaks out, where does it go? Is there some way to
collect it and put it in another tube, to make it last longer?
You have to suck really hard.
FAQ #16j. No really, how do I know a tube is broken?
Usually a tube whose glass has been broken or cracked usually will have a white powdery like substance inside it
where all that silvery stuff used to be. No, it is not cocaine and we didn’t put it there.
FAQ #16k. Does the glass explode?
I haven’t seen it happen. Usually the glass will just crack at the base of the tube if it is going to physically break due
to a sudden change in temperature and “all the vacuum will leak out”.
FAQ #16l. Other than outright failure of a tube, how do I know when it is time to re-tube?
Generally speaking, for the small tubes, if you notice an unacceptable increase in background noise (“hiss”) then
the tube who is responsible for making the gain in the circuit probably needs to be replaced. The tube(s) making
the gain will usually be shorter than the output tube. Common types we use for gain in most of our circuits will be
12AT7, 6201, 12AU7, 5814, 12AX7, 5751, or 6072. The output buffer tube in most of our line-level circuits will be
either the 7044, 6414, or 12BH7. These tubes usually don’t cause too much trouble and either work or don’t work.
Turn the lights off and see if you see the little tubes glowing. Look for one that looks like it has cocaine in it.
For the power tubes in our amplifiers, after a few years if you notice a small revolt going on where several of the
output tubes are misbehaving or getting hard to bias, you might consider doing a full re-tube. Keep the old ones that
did not join the revolution as emergency spares.
FAQ #16m. Can I change a tube myself?
R.T.F.M.
Do you call in specialists to change your light bulbs for you?
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