Valves - how can you tell if they are blown? - Jemsite
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post #1 of 4 (permalink) Old 08-11-2002, 02:42 PM Thread Starter
Join Date: Nov 2001
Location: Birstall, United Kingdom
Posts: 295
Valves - how can you tell if they are blown?

I had a Cornford Harlequin delivered on Friday and I am not impressed with it. It doesn't have a nice "creamy-smooth" distortion and sounds quite bad. After a lot of talking with people, my Cornford *might* have a dead valve.

How can I tell if a valve is dead? I was told that I should look to see if they are glowing - mine only has a glowing tip (slightly glowing) after 5mins of it being on.
The other 2 valves I cannot see as there is a metal tube casing around them.

Anyone got any pics of them glowing so I can compare?
This amp will go back monday and will get an Ashdown Peacemaker 40 instead if it looks knackered


(BTW this is my first valve amp, not including my Marshall AVT20)
WildWayz is offline  
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post #2 of 4 (permalink) Old 08-11-2002, 06:28 PM
Join Date: Dec 2000
Location: LR, AR
Posts: 1,982
when i was having tube/valve issues, i would gently tapp each tube with a pencil to see if they would squeal or check if they were lighting up. is an excellent site for tube info as well as good prices on tubes. is as well. when i had retubed my 5150 i went thru the same feelings you did, but mine was a noise issue, not tone. the way i felt about it was, replace the tubes, it won't hurt it(preamp-wise).

rty13ibz98 is offline  
post #3 of 4 (permalink) Old 08-11-2002, 06:37 PM
Join Date: Aug 2002
Location: G
Posts: 49
my tube blown

Well when my tube blown is scared the s**t out of me...
There was a great blue flash and the smell of smoke. It scared me but it was cool. Then i replaced all tubes in the classic 30 with groove tubes (I like those) and haven't had any trouble since. But then orcourse, I've been playing that amp for about 4 years or so...
When in doubt, replace (I wanted to get those cheap japanse things out anyways)
guitarpicker2006 is offline  
post #4 of 4 (permalink) Old 08-12-2002, 11:01 AM Thread Starter
Join Date: Nov 2001
Location: Birstall, United Kingdom
Posts: 295
The valve seemed fine... I sent the amp back and ordered a Ashdown Peavemaker 40 instead. Same speaker, same valves as the Cornford, but 40watts, 3 channels, effects loop etc
And it was only 299

WildWayz is offline  

groove tubes , marshall avt

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