Bluesbreaker - No sound

bum

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Hi all :)
Hoping someone can help me out.
I have a Bluesbreaker, reissue. Always flight cased, never dimed and is now my home amp, so has not moved in well over a year.
Today I get zero sound, I turn the amp up full, no buzz, nothing.
Checked speaker cable, all looks good, it is in brand new condition pretty much throughout and has been looked after.

I notice one of the power tubes seems way brighter than the other, pic attached.
Any ideas on this, it's a real headscratcher.
Things tried: All 4 inputs, tried 2 guitars, 2 cables and also a wireless system

Thanks all!

valve.jpg
 

DarrellV

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Hi all :)
Hoping someone can help me out.
I have a Bluesbreaker, reissue. Always flight cased, never dimed and is now my home amp, so has not moved in well over a year.
Today I get zero sound, I turn the amp up full, no buzz, nothing.
Checked speaker cable, all looks good, it is in brand new condition pretty much throughout and has been looked after.

I notice one of the power tubes seems way brighter than the other, pic attached.
Any ideas on this, it's a real headscratcher.
Things tried: All 4 inputs, tried 2 guitars, 2 cables and also a wireless system

Thanks all!

View attachment 552633
I'm not an amp pro but from that pic it looks to me like the filament (heater) in that power tube has shorted and is burning way hotter in the shorted area.

I would try replacing that one first.

If it has shorted near the bottom like you see, it is likely not heating up the entire cathode leaving it cold, hence no output.

Likely hasn't hurt anything yet, nor blown the fuse , so just get it changed...

My 2 cents

1627760279118.png
 

bum

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Cool thanks, I am checking out replacements, it sure doesn't look right, it gets very bright very quick.
Can I pull that tube and try to see if I get anything? I don't want to fry anything but if it's safe to do I will give it a go
Thanks :)
 

bum

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Update: Pulled the tube and...

valv2.jpg


Yikes
 

DarrellV

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Update: Pulled the tube and...

View attachment 552667

Yikes
What's the yikes for?

Those silver black patches on the glass are normal, if that's what you're concerned with..

It's called 'getter' and it's a powdered chemical they put in the tube during assembly.

Once the air is sucked out of the tube and the glass is sealed they heat the outside to burn the powder inside.

The powder eats up more air inside as it burns, increasing the tube efficiency.

The filament is in the very center and you likely can't see it. It's very thin and fragile.
 

bum

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OK cool thanks for the info :)
I have ordered a pair of new ones so will try that, the way it is lighting up still makes me think it's toast so hopefully this sorts it.
Got em from Watford Valves who I have used in the past, I like them.
The product description also says:
"This valve was originally designed to withstand 3G as it was used in the servo motors of Russian fighter Jets." :jam:

Which is metal as hell ha ha
 

DarrellV

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The product description also says:
"This valve was originally designed to withstand 3G as it was used in the servo motors of Russian fighter Jets." :jam:

Which is metal as hell ha ha
:lol::applause:

Love it!!!

A pair is the way to go as well, I forgot to mention that.

When my Magnatone power tube lit up like a sparkler inside a few weeks ago I got a replacement pair.

They are matched output. I had forgotten that. So they should be replaced as a pair.
 

bum

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Yeah I got a matched pair from Watford Valves, they seem to really care about their stuff and test / match valves themselves.
I'll see how I get on, thanks again for the help :)
 

Cjsinla

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That tube looks like it may be original to the amp, might be old and worn out. You will need to check the bias when you put in a new pair.
 

bum

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That tube looks like it may be original to the amp, might be old and worn out. You will need to check the bias when you put in a new pair.
It is what came with the amp for sure, the amp was used once a week and is maybe 3 years old, if that helps.
I dunno, maybe just one of those things? I have two new ones on their way :)
 

Cjsinla

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It is what came with the amp for sure, the amp was used once a week and is maybe 3 years old, if that helps.
I dunno, maybe just one of those things? I have two new ones on their way :)
No, 3 years isn’t that old but sometimes tubes go bad. It looks way too bright in the pic. It’s hard to tell why that might be without opening the amp and checking some voltages. The easiest thing is to check fuses and swap in new tubes.
 
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ARandall

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Power amp tubes go bad often due merely to being 'on'. The high bias levels of some amp designs make for very short tube life. The EL84 and typical 6V6 ones are super hard on power tubes even without anything more than bedroom volumes being used. All of my 6V6 amps use up their tubes in about 2 years.
 
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bum

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Good to know thanks guys, these are 5881's new ones should arrive soon :)
 

rogue3

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Good to know thanks guys, these are 5881's new ones should arrive soon :)
You need to be sure your grid resistor did not get smoked in the process. Runaway bias> as in none. That event would likely have blown a fuse as well. When guys stick foil in the fuse socket,it blows transformers too. Proceed with care.

When you get the new tubes,don't just stick them in.Get someone knowledgeable to get a meter on your chassis and check all your internal voltages, and bias,to be sure nominal values are present.If there is a fault,and you don't check,you'll toast the new tubes too!
 
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bum

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I will ask my amp dude to have a look for sure, these things scare me / I don't want to die
 

bum

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OK, update, here is the H T Fuse:

htfuse.jpg


What I am hoping is the faulty tube caused this to blow, and I now have these just arrived:

5881.jpg


So fingers crossed!
 

irocdave12

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I definitely think you are on the right track Bad tube took out the fuse which did its job. On power tubes as a rule of thumb they should be expected to start dropping off in performance after about a year especially with the lower quality new production tubes. If you play a lot then could be sooner. Dont be surprised if the amp sounds like a new amp suddenly. You never noticed the slow steady drop off but you definitely notice the instant improvement with new tubes immediately
 
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bum

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I think you are right, the amp is only a couple of years old, I got it off a pro guitarist who was given 2 of them brand new to play at The Brits (a big music awards in the UK) - So this meant they were used once then put in flight cases and sold on. It came with documentation off electricians / testers who must have had to test it prior to the awards gig, it was a strange experience picking it up as it was in storage along with Pink's stage scenery, very weird seeing all that!
Anyways, I used it once a week, but we rehearse for a good 8 hours straight at drummer volumes, so it did get a work out.
For the past few months it's been my home amp, low volume, so maybe I didn't pick up on any gradual degradation.
Waiting for the fuse to arrive, but great to hear I may be on the right track :)
 


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