#1
Hey everyone,

Just need a bit of help. My warp 7 hughes and kettner amp has a problem. What happens is after about 15mins it starts fading in and out. The problem is that the fuse is overheating in the amp. I think this is because it was sitting slightly loose in the fuse holder, not because too much current is going through. I have taken them out and put them back in but if this doesn't work i may try putting a fan in the amp head to cool the fuse and stop it overheating. So i have three options, what would be the best?

1) Secure the fuses better with electrical tape and squeeze the fuse holders in more with a pair of pliers

2) Change the fuses, would it be possible that they might be worn out or faulty?

3) Put a fan in the amp head, would this work to cool the fuses down or would it just do damge to other things in the amp if the fuses were being cooled?

Hope someone can help me

Thanks
Gear:
SQ Custom 1, Washburn G-JRVs x3, Yamaha ERG121C, Samick Interceptor, Encore Acoustic, Vintage 5 String Bass, Unbranded Red Bass.
Line 6 SpiderII Halfstack, Laney/Carlsboro Halfstack.
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#2
Just to point out, when i say fading in and out, i mean it fades out, then when i stop playing it fades back in, i'm guessing its the fuse expanding and breaking the circuit then when i stop playing the fuse contracts and i can play again at full volume until it expands and the sounds fades out again.
Gear:
SQ Custom 1, Washburn G-JRVs x3, Yamaha ERG121C, Samick Interceptor, Encore Acoustic, Vintage 5 String Bass, Unbranded Red Bass.
Line 6 SpiderII Halfstack, Laney/Carlsboro Halfstack.
Crybaby,Whammy,Flanger,Stage Tuner,Tremolo,Bass Overdrive
#3
Sounds like you should return it and get a fully working one so it wouldn't be an ongoing problem if you still could.

If its blowing fuses, that usually mean a tube is bad and replacing the fuses would just blow them again. Maybe the tubes are biased too hot? I don't know for sure.
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#4
a fuse won't be intermittent like that, it will either work, or the filament will melt and it won't work again. That's how they are designed. My guess is it is more likely your tubes are going, or something like a solder joint is heating up and expanding somewhere, or even a bad component. If it's new, take it back. If not, I would explore new tubes first. Is the amp getting plenty of airflow? Like it's not pushed right up against a wall or something, or nothing blocking the vents right?
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#5
If the fuse holder is not working properly anyway, maybe you should switch to using a circuit breaker. Why do so many amps still use fuses anyway?

I don't know much about tube amps so I don't really have any suggestions, sorry.
#6
Economics, a fuse is what 10 cents or less and a circuit breaker is a couple of bucks. Its all the little stuff they make money on. And fuses dont run hot as said they either pop or they let current thru. A fuse isnt intermittant and they dont really wear out. So its tubes or an internal problem.
#7
Quote by Erock503
a fuse won't be intermittent like that, it will either work, or the filament will melt and it won't work again. That's how they are designed. My guess is it is more likely your tubes are going, or something like a solder joint is heating up and expanding somewhere, or even a bad component. If it's new, take it back. If not, I would explore new tubes first. Is the amp getting plenty of airflow? Like it's not pushed right up against a wall or something, or nothing blocking the vents right?

+1. Beat me to the punch. Fuses blow, kill power to everything, and don't come back.
#8
Probably should have pointed this out before but i'm fairly sure the Warp 7 is a solid state amp head so i'm guessing it probably not the tubes that are wearing out. So what could it be if its not tubes wearing out? If its a problem with something else heating up would trying to put a small battery fan in the head, work to cool it all down? (seeing as most of the suggestions i have been given say its something heating up)

Also would it be a good idea to take the amp out of the head casing and playing guitar through it to find out what it is thats heating up?

Thanks
Gear:
SQ Custom 1, Washburn G-JRVs x3, Yamaha ERG121C, Samick Interceptor, Encore Acoustic, Vintage 5 String Bass, Unbranded Red Bass.
Line 6 SpiderII Halfstack, Laney/Carlsboro Halfstack.
Crybaby,Whammy,Flanger,Stage Tuner,Tremolo,Bass Overdrive
Last edited by punkguitarist01 at Jun 9, 2008,
#9
Right for the diagnosis let's think about it properly.

He says it's fading in and out. How fast is it fading in and out? What parts could cause it to fade in and out?

- Capacitors
- Resistors
- Transistors

Is it an even fading in and out, like oscillating, if it is, then a capacitor could well be a problem, if it's not, then a resistor or a transistor is more likely the problem.

Does it fade all the way out to no volume & then back again?

If it does, the most likely problem is a transistor, if it doesn't, more likely a resistor.


Give more info, I'll try to get a bit more precise.
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#10
Thanks Mcw00t, sounds like you might be able to help me, to answer your questions

It fades in and out after playing for 20 minutes and it fades out while i'm playing, then when i stop and let a chord ring the volume fades back in again most of the time. When i say fades in and out - it fades to a very low volume (still audible) which will stay at the same level and i can play at that level, with the clarity still there until i let that chord ring out then it rises back to high volume usually, hope that makes sense, if not tell me and i'll try and write it out again

Thanks
Gear:
SQ Custom 1, Washburn G-JRVs x3, Yamaha ERG121C, Samick Interceptor, Encore Acoustic, Vintage 5 String Bass, Unbranded Red Bass.
Line 6 SpiderII Halfstack, Laney/Carlsboro Halfstack.
Crybaby,Whammy,Flanger,Stage Tuner,Tremolo,Bass Overdrive
#11
Quote by Tackleberry
Economics, a fuse is what 10 cents or less and a circuit breaker is a couple of bucks. Its all the little stuff they make money on. And fuses dont run hot as said they either pop or they let current thru. A fuse isnt intermittant and they dont really wear out. So its tubes or an internal problem.


I think there's a better reason than economics for fuses. Even $2000+ amps have them and the makers wouldn't think twice about using a $10 circuit breaker if it would work.
Circuit breakers are mechanical, which means they can break or not work when they are needed and you don't this to happen to your expensive amp.
Fuses are 100% safe, if they're broken (either by excessive current or by dropping it) your amp is safe. If a circuit breaker is broken, your amp can be at risk.
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#12
You will be surprised at how far even high end companies will go to save a few cents. A 10 dollar breaker or a 10 cent fuse. That would be 9.90 in their pocket. And breakers arent that unreliable it takes a long time for em to wear out or go bad. Long after any warranty period. So its pretty much pure economics. As for the tubes the HK site lit several WARP amps some are tube some arent. As its SS it could be a real problem to figure out whats going on. One of the downs sides to SS is diagnosis. A fan may delay the problem but may be time to find another amp.
#14
Quote by punkguitarist01
Thanks Mcw00t, sounds like you might be able to help me, to answer your questions

It fades in and out after playing for 20 minutes and it fades out while i'm playing, then when i stop and let a chord ring the volume fades back in again most of the time. When i say fades in and out - it fades to a very low volume (still audible) which will stay at the same level and i can play at that level, with the clarity still there until i let that chord ring out then it rises back to high volume usually, hope that makes sense, if not tell me and i'll try and write it out again

Thanks

Hmm, interesting, sounds almost like it could be a power supply problem. In fact, that may well be what it is. Either that or a power transistor problem, but more likely the latter.

Reason I say this, is that if the power supply is faulty, then it's not going to like large currents being drawn from it, ie, when you're playing a loud note/chord. As that fades, the current trying to be drawn falls, and the supply can then cope with it again, somewhat poetically causing the volume to rise.

To test this, could you turn down the master volume of your amp and let the chord ring out and change the volume and see if the point where it cuts back in loud changes dependent on the volume. my suspicion would be that at lower volumes, it would cut back in sooner than at higher volumes.

However, as helpful as I can try to be over the internet, at the end of the day, I'm not going to be able to do anything with it. It sounds like an electrical fault that's not easy for an untrained person to fix. My advice would be to take it to a shop, where they'd be able to take a proper look at it and do all the diagnostic tests I'd like to do, but for obvious reasons, cannot.
OMG!!! They're playing One!!!!!11fade to black11one11

God & Founder of UG Electronics


Electronics God of the Laney Cult

My Gear:

Ibanez RG370DX
Laney VC30-212
Dunlop Crybaby
Boss CS-3
Ibanez TS9DX
#15
That does make sense as when i turn it down it seems to go for longer without fading in and out and yeah it does come back in quicker when i turn the volume down, what would be the best way to fix it/what would need to be replaced if it is a power supply problem? (I have tried switching the power supply lead and it still has the same problem)
Gear:
SQ Custom 1, Washburn G-JRVs x3, Yamaha ERG121C, Samick Interceptor, Encore Acoustic, Vintage 5 String Bass, Unbranded Red Bass.
Line 6 SpiderII Halfstack, Laney/Carlsboro Halfstack.
Crybaby,Whammy,Flanger,Stage Tuner,Tremolo,Bass Overdrive
#16
I think you'd have the replace the power supply. I think it might not be worth it to fix the amp - go ask some tech how much it would cost. Often it would cost too much (with SS amps) to be worth it.
Quote by Lunchbox362
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#17
What do you mean replace the power supply? Do you mean the cable or something else in the amp? I want to get it fixed as i like this amp and i'm getting married this year i need to save money and getting it fixed will be a lot less than what i paid for it.
Gear:
SQ Custom 1, Washburn G-JRVs x3, Yamaha ERG121C, Samick Interceptor, Encore Acoustic, Vintage 5 String Bass, Unbranded Red Bass.
Line 6 SpiderII Halfstack, Laney/Carlsboro Halfstack.
Crybaby,Whammy,Flanger,Stage Tuner,Tremolo,Bass Overdrive
#18
Well, to be honest, I'm just guessing here. I suggest you just take it to a tech and have him see what the problem is and how to fix it. If the problem is in the power supply tho, you'll have to replace the power supply in the amp, and that's not gonna be terribly cheap (the part will cost some, and the labor will probably cost a lot).
Quote by Lunchbox362
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#19
Yeah i think i will take it to an amp tech, hopefully it won't cost too much but as its a power supply hopefully the techs will be able to get a replacement, if it is that. If that doesn't work i can get hold of the hughes and kettner dealer in London and ask them to send me one
Gear:
SQ Custom 1, Washburn G-JRVs x3, Yamaha ERG121C, Samick Interceptor, Encore Acoustic, Vintage 5 String Bass, Unbranded Red Bass.
Line 6 SpiderII Halfstack, Laney/Carlsboro Halfstack.
Crybaby,Whammy,Flanger,Stage Tuner,Tremolo,Bass Overdrive