#1
Hey out there, I am a tube amp greenhorn and could use some sage advice about what the heck happened to my Amp and what I can do to fix it. I bought a used (obviously) Peavey Encore 65 about 2 years ago on Ebay and have enjoyed playing around with it. I was playing last weekend and there was a “pop” sound and all the lights went out.

Now the amp is dead, no power at all. Leading up to the death of the amp I didn’t hear any difference in the sound to let me know there was a problem. To me it seemed that I blew a fuse but I have looked at the thing and can’t see where the offending fuse may be. Another thing I was thinking was that one of the tubes might have blown, would that cause the amp to go completely dead?

I pulled out the tubes thinking that I should probably replace them considering they are like 30+ years old at this point. Is there any way to tell if a tube is bad by looking at it? If so it would be great to see what a blown 6L6GC power tube looks like.

I know that I should replace both the power tubes at the same time (like brakes on an axel) but do I need to replace the preamp tubes as well?

Generally I am a DIY kind of guy and I want to avoid paying a shop $80 to bench test a $75 amp. I have looked on the internet but I can’t find a wiring diagram or even a schematic of how the Encore 65 is set up. If anyone could point me in the right direction I would sure appreciate it!
#3
Quote by Bearshrimp
I was playing last weekend and there was a “pop” sound and all the lights went out.

Now the amp is dead, no power at all. Leading up to the death of the amp I didn’t hear any difference in the sound to let me know there was a problem. To me it seemed that I blew a fuse but I have looked at the thing and can’t see where the offending fuse may be. Another thing I was thinking was that one of the tubes might have blown, would that cause the amp to go completely dead?


i was going to recommend changing the fuse, but what caused the amp's fuse to blow may be a whole different problem in itself.

i looked at the manual

http://www.peavey.com/media/pdf/manuals/80300051.pdf

there is no reference to a fuse that i see. i have heard they will place the fuse in the chassis sometimes...



i tried to find some gut shots of your amp, i got a pic of this peavey envoy instead. but you can see a fuse on the left side of the chassis.

Quote by Bearshrimp
I pulled out the tubes thinking that I should probably replace them considering they are like 30+ years old at this point. Is there any way to tell if a tube is bad by looking at it? If so it would be great to see what a blown 6L6GC power tube looks like.


the tubes may not be bad. i have some old amps (from as early as the 50's) with the original tubes in them. if your amp is old enough you may have some quality Q/A'd american tubes in there and they can last quite a while.

many times there won't be a visual indication that the power tubes are bad. sometimes you can see a burn type mark on the tube, sometimes you can see the getter has gone bad (indicating an abundance of air in the tube). sometimes you can even see parts of the tube rolling around the inside. but usually it just looks like any other tube.

Quote by Bearshrimp
I know that I should replace both the power tubes at the same time (like brakes on an axel) but do I need to replace the preamp tubes as well?


i usually replace all power tubes at the same time because they generally require a 'matched' set. you don't necessarily need to replace the preamp tubes as well, i wouldn't worry about it unless you think one is bad.

Quote by Bearshrimp
Generally I am a DIY kind of guy and I want to avoid paying a shop $80 to bench test a $75 amp. I have looked on the internet but I can’t find a wiring diagram or even a schematic of how the Encore 65 is set up. If anyone could point me in the right direction I would sure appreciate it!


you can probably contact peavey's customer service to get a schematic. i briefly looked online with no real success.

i will warn that tube amps usually hold a lethal charge, so you should really know what your doing when servicing more than tubes or a fuse. be careful of the capacitors in that amp cuz they'll hurt ya bad if you don't discharge them.
punk isn't dead, it's always smelled that way.

"A perfection of means, and confusion of aims, seems to be our main problem."
-ae
#4
Hey gumbilicious thanks for the advice, do you think it sounds more like a bad tube or a bad fuse? From what I have seen online a bad tube usually does not kill the power but can cause a fuse to blow so its a chicken or the egg type issue. I don't want to waste money, but I would like to put a new set of tubes in that thing if I can get it back up and running. I did love the sound and I am not looking forward to finding a replacement
#5
Quote by Bearshrimp
Hey gumbilicious thanks for the advice, do you think it sounds more like a bad tube or a bad fuse? From what I have seen online a bad tube usually does not kill the power but can cause a fuse to blow so its a chicken or the egg type issue. I don't want to waste money, but I would like to put a new set of tubes in that thing if I can get it back up and running. I did love the sound and I am not looking forward to finding a replacement


your symptoms def sound like the fuse went. but as you mention: what caused the fuse to blow?



you can test tubes, but you need to find someone with a tube tester and they may charge you something.

what i'd do is pull the chassis, check for a fuse in there are replace it and try to fire the amp up. see if it sounds funky or if the tubes are flashing crazy colors or red plating or not firing up.

if the tubes seem bad then i'd use one of my spares to see if it helped the problem (a guitar shop may let you try one of their tubes if they are cool). if it did help then i'd order a new matched set and get the amp re-biased to the new power tubes.
punk isn't dead, it's always smelled that way.

"A perfection of means, and confusion of aims, seems to be our main problem."
-ae
#6
Quote by gumbilicious
your symptoms def sound like the fuse went. but as you mention: what caused the fuse to blow?



you can test tubes, but you need to find someone with a tube tester and they may charge you something.

what i'd do is pull the chassis, check for a fuse in there are replace it and try to fire the amp up. see if it sounds funky or if the tubes are flashing crazy colors or red plating or not firing up.

if the tubes seem bad then i'd use one of my spares to see if it helped the problem (a guitar shop may let you try one of their tubes if they are cool). if it did help then i'd order a new matched set and get the amp re-biased to the new power tubes.


Can't think of a better way to spend Labor day than being elbow deepin the guts of an amp, thanks!
#7
Fuses don't go bad. If there is a blown fuse, then there is something drawing enough amps on that circuit to cause it to blow, and a blown power tube can certainly do that. You can try installing a new fuse to see if it will come back to life, but in all likelihood (and especially in the case of a blown power tube) it will immediately blow the fuse again. If this occurs, try another set of power tubes and another new fuse, as that is a good place to start. Pay attention to the type of fuse used as well, as they can be a slow blow or fast blow, and it does matter which you use.
#8
Quote by 4FunandProphet
Fuses don't go bad. If there is a blown fuse, then there is something drawing enough amps on that circuit to cause it to blow, and a blown power tube can certainly do that. You can try installing a new fuse to see if it will come back to life, but in all likelihood (and especially in the case of a blown power tube) it will immediately blow the fuse again. If this occurs, try another set of power tubes and another new fuse, as that is a good place to start. Pay attention to the type of fuse used as well, as they can be a slow blow or fast blow, and it does matter which you use.
Fuses do go bad... They're made of a delicate metal, you think that metal is going to be in the same shape in 30 years? Even if you kept it in temperature controlled storage for that time I'd question it, but you're running current through it on a regular basis. They can wear out.
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#9
Indeed, fuses can simply fail on their own accord. Replace the fuse, if it blows again then it was caused by some other fault, probably dead power tubes.
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