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I own a Peavey Ultra Plus 120 head.

Lately, whenever i've been switching from the power to standby, i hear a crackling noise.

Just now, i switched it on(waited a minute to warm up), i heard a loud crackling noise, followed by the amps status lights to shut off.

The cab is connected properly, theres no smoke, no nothing. When i power it on no lights come on, it's dead. What can I do? This is my first tube amp and ive owned it for about 2 months.

Could it be a fuse? I doubt its a tube, the whole amp is dead. What can I do by myself without taking it to a tech?

It could be a tube, most amps wont work if one tube blows. have a look at them, if one is black around the top, it could be blown. That and check the fuses too
i have a gig next friday..

Can't i get fuses from a local guitar shop? They service amps too.. but i dont really have alot of money.

What do you mean main fuse? theres a fuse that controls the whole amp and if it goes then the whole amp goes? How can i see it or tell if its blown?

And where can I see the fuses? I dont know where to look.
Have a look at the back of the head. It should be there, near the power cord socket. Im not sure if it is there but it should be. Take it out and if the wire in the fuse is broken, the fuse is blown
Yeah take it to a Music shop,for a look dont have to pay and they'll let you know what your problem may be,Hopefully for your sake its just a tube...i have an old Amp that i got from one of my grandparents sisters,it looks like its from the freakin 60's,sounds F-in clean ,worked for about a year,then a tube went out.i got a diff amp. but just found out that old amp works with a freakin bass head i had lying
Gather the Faithful and Propose a toast!

****ing moron. Listen to what we said.

-Open the grate with a screwdriver and check to see if the tips of the tubes are black
-Look online or use the manual and find where the fuses are

Seriously. Why is it so hard for people to try something and see what happens instead of just asking for answers constantly.
1. I looked at the power tubes and they're both dusty but not black.. at least to my eyes.

2. Even before i made this thread i tried to find a PDF of the manual or even schematics with no luck..

I was looking at the tubes from the top grill though, i'll open the back and see if anything is different
Pictures of the tubes..

That black hazy outline i think was already there.. i bought the amp used. When the amp is on, that black area turns purple. It was already like that. I don't know if it's bad or not but it wont turn on at all..

How does it look to you guys?
worst case - ping IbanezPsycho - he has an Ultra and is and amp tech.

what is that black circle thar inbetween the copper jacks?

no lights tells me it is a main fuse, but i'm not an amp tech. Any other fuses would need to be replaced by an amp tech imo.

the mains fuse on my Valveking for example is a F3A. It has a slot on it so that I can use a flat head or a coin to take it out. Look at it like you would a car fuse. Call around until you find one locally. Somebody should have one.

The crackle could have been a power tube or a preamp tube going bad, but I would guess the light would still come on.
the tubes dont seem to be the problem, but we'll see when i take it into the shop..

any way to check if fuses are blown? i'm not sure what you guys meant about near the power cord..
I though the fuses would be where the cord attaches. Seeing the pic you posted, they arent. That means theyre inside the amp. Let a tech have a look at it, you could electrocute yourself if you go poking round in there.
okay i'll let the tech look at it

i'm just sad i wanted to have a jam session right now with myself
time to work on playing acoustically.

never hurts.

so there is no fuse on the back??

Seriously PM IbanezPsycho, post in the VK or JSX/Ultra thread, and search for schematic.

Ultra was predecesor to XXX I think.

(i see you posted in JSX/XXX/Ultra thread.)
Last edited by 311ZOSOVHJH at Oct 31, 2008,
no i didnt see any fuses..

im sure i would be at the shop already before ibanezpsycho gets a chance to check his pm's

if worse comes to worse i'll just borrow my friends Mesa dual caliber amp for the gig :licklips:
its a good idea to try amp on another electricity plug on other rooms. may be the problem arises from the plug. but a guess
The Life = A Place To Waste Energy
Didn't work when i plugged it into another outlet.

I called a local tech and he quoted me $60 just to open it up and find out whats wrong with it.

i don't really have that kind of money right now.. arghh
It looks to me like a fuse. If you can find the HT Fuse (what it's called) and replace it with a new version of the exact same one then you should be fine. Also, your valves are fine to my eyes.

Edit: The fuse isn't really your problem, it's what caused the fuse to blow in the first place. Here's some stuff off the top of my head:

1. Bad Power valves (unlikely due to pics)
2. Bad Preamp Valves
3. Power Surge
4. Badly seated valves (i.e not pushed in properly, causing arcing)
5. Old fuse (it happens)
6. Component burnout (have a look at the circuit boards, any scorching?)
7. No speaker load connected or load ismatch, causing the Output Transformer to give up (not likely from what you've said - the cab and head ohm ratings match right?)

They are loads of other more technical things it could be, but a lot of fuse blowing is to do with those things.
Last edited by bartdevil_metal at Oct 31, 2008,
Just read another thread looking for some info for you. There are fuses for these amps. No one came out and said where, I'm going to assume it is inside.
You should of hit me up when I got up this morning. I could have told you about the shop costs and gave you the below info so you could have been working on it all day.... :stickpoke

The Fuses are internal, meaning you have to remove the chassis to get to them.

Theres gonna be two of them side by side. To do so you need to remove the back plate and remove the tubes, unscrew the side screws to remove the front plate and disconnect the channel light from the amp, unplug the reverb tank and be careful the wiring is old and not the greatest so dont yank on the wires, then your going to unscrew the rubber feet screws that hold the amp and chassis in place, then slide out the amp from the chassis, flip it over and look for the fuses and check them out.

Also smell and look for any burnt components or anything that might look out of place that could have cause something to blow.
Last edited by IbanezPsycho at Oct 31, 2008,
I dropped it off without thinking at another shop. They said it was $30 to open it up and figure out what was wrong.

I probably could have checked it out myself but what the hell

we'll see what happens..
Quote by injected
I dropped it off without thinking at another shop. They said it was $30 to open it up and figure out what was wrong.

I probably could have checked it out myself but what the hell

we'll see what happens..

$30 bucks for a diagnostic is pretty good actually..
I paid $3.25 for 4 new fuses at radio for my Valveking.
Just letting you know
^^Did you have the same amp symptoms as me?

The amp would have no response to turning on and off?
Oh also, how did you guys know it was the fuses? Is there a way of telling just by looking? Or did you guys just replace all the fuses on a hunch?

I'm talking to you^^ mr. $3.25
Your amp is not taking power right? Typically that is a good indication that you've blown a fuse. Fuses blow. We're not saying that is it exactly. How would we know being that we are on the internet.

xBOPx is just saying he got a pack of 4 of them for $3.25, which is what you should be doing. I don't think most tube amp have more than 2.

You could have had a tube blow and it caused the fuse to blow too, but it is cheap and easy to replace the fuse and go from there.
The tech is not going to take the amp until tomorrow morning.

How hard is it to crack open the fuse box? How do I know what kind of fuses I need?

I can really use the extra $30 from just inspecting it, i can't spare that much money at the moment. I think i'm going to go grab it and replace the fuses, but I need your guys' help :P
Oh, and is there more than one fuse?

I've been searching for fuse threads on here and most of all the threads say, I replaced the fuse. I thought there would be like a huge panel of fuses that i need to inspect, or is there just one main magical fuse that would be broken? thanks
I have no clue on the Ultra but if I had to guess there are probably 2. One for over all amp (mains) and one for the power tubes. If a power tube fuse blows then you still get power to the amp and the light comes on etc. That is there to protect the rest of the amp in case of a power tube problem.

Just follow IbanezPsycho's advice he laid it all out. Also check for a users manual on-line. I'd be shocked if there was not one.
Last edited by 311ZOSOVHJH at Nov 2, 2008,
Oh, I overlooked ip's post. Will certainly try that when i get my amp back!
Got the amp back right now, gonna start taking it apart. If someone or a few people want to stick around this topic because i'll likely be bumping it with questions and pictures as i progress taking it apart..
Alright, got it cracked open

Which one of these are the fuses? There's 2 white thingies on the bottom that say T1A FUSE. I dont know if those are the mains or HT's or what. Right now i think i'm going to replace the mains fuse because it wont turn on.

There's also two more "fuses" on top of those. One says T-2A Fuse, and another one is covered in some sort of white cover that doesnt read anything. How do i proceed?

edit: Forgot the picture!

Update, I just called Peavey to ask about what kind of fuses but the two guys working there weren't answering... anybody have any idea what i can pick up at radioshack? lol

Still don't know what the main fuse is..
I'm not sure if I can help or not but download the Ultra user manual off and then find your schematic for amp on this site.

Did you buy new fuses? If not, then don't mess with anything. Go get some fuses first and for gods sakes be carefull not to touch any capacitors just the fuse itself. Write down the fuse numbers and go get some. They're cheap. Bump.
that seems like an outrageous place for tubes to be. They should put the main fuse right in the back with easy access. Anyways I blew like 3 fuses on my fender amp and took it in they just plugged a new tube in and it worked fine, so bad tubes will cause your amp to blow its main fuse.
Quote by Bubonic Chronic
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For girls it's like "here's're fat!"
The amps been unplugged for almost a week, i think the capacitors are drained.. but i will note it. i'm guessing they're the things that say 100V 100V 100V on them..

Also they dont have the ultra plus on that site

and yeah i figured it was the tubes. My powertubes look fine but i think i'll replace them anyways. How about preamp tubes, do they cause the main fuse to blow?
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