Dead Valve ?

[Machines]

Just went for a bash on my ABM - the valve circuit has ceased to function ! The further up I turn the knob, the quieter the signal becomes (since it's a hybrid circuit).

I did the best I could muster by taking it out, looking at it sternly and putting it back in, but alas it was the same.

Does that just sound a like a replacement valve is needed ?

[Kiwi]

[quote name='Machines' post='111590' date='Dec 31 2007, 06:53 PM']Just went for a bash on my ABM - the valve circuit has ceased to function ! The further up I turn the knob, the quieter the signal becomes (since it's a hybrid circuit).

I did the best I could muster by taking it out, looking at it sternly and putting it back in, but alas it was the same.

Does that just sound a like a replacement valve is needed ?[/quote]

If the valve does anything other than gently glow orange when the amp is switched on, then its likely that it has gone in some manner. Can you check it in a darkened room? 12AX7's aren't too expensive thankfully.

[EBS_freak]

[quote name='Machines' post='111590' date='Dec 31 2007, 06:53 PM']Just went for a bash on my ABM - the valve circuit has ceased to function ! The further up I turn the knob, the quieter the signal becomes (since it's a hybrid circuit).

I did the best I could muster by taking it out, looking at it sternly and putting it back in, but alas it was the same.

Does that just sound a like a replacement valve is needed ?[/quote]

Could be a good start - if you are up to it, take it the chassis out and see if the tube is at least lighting up... but don't blame me if death results...

[Machines]

I'm a computer engineer so it can't be too different, right ?!

I wasn't aware that they glow, I thought that was limited to all tube amps so I will check it out tomorrow.

Cheers chaps.

[The Burpster]

I'm gonna git me a valve checker and balancer in the new year, then while he still has enough nouse I'll get my Pa to tell me how to do it.....

I know theres a couple of Valvophiles on here and I'll never be one of them, but a warm glowing valve is a wonderful thing to behold......

[EBS_freak]

[quote name='Machines' post='111606' date='Dec 31 2007, 07:34 PM']I'm a computer engineer so it can't be too different, right ?!

I wasn't aware that they glow, I thought that was limited to all tube amps so I will check it out tomorrow.

Cheers chaps.[/quote]

I'll let you work out the difference of touching a motherboard running at 5v and 12v dc and touching an amp

[Kiwi]

[quote name='The Burpster' post='111624' date='Dec 31 2007, 08:47 PM']I know theres a couple of Valvophiles on here and I'll never be one of them, but a warm glowing valve is a wonderful thing to behold......[/quote]
Nothing beats the smell of a warm tube amp, its nearly like the smell of a warm cat...

[EBS_freak]

[quote name='Crazykiwi' post='111639' date='Dec 31 2007, 09:31 PM']Nothing beats the smell of a warm tube amp, its nearly like the smell of a warm cat...[/quote]

Indeed.

[The Burpster]

IS that warm- damp- cat? Am I on the correct track now.....


BTW check these puppies out..... Me want one........

[url="http://www.biasking.com/"]http://www.biasking.com/[/url]

[Machines]

I found a Sovtek 12AX7 on eBay for £10 inc delivery, sound ok ?

[The Burpster]

Matt.

£10 seems ok. You will have to chuck a big load of trust at ebay as it could be cack.....

Sovtek are OK but if you can find Mullard, Mesa or Groove Tubes.... they would be my recomendation(in that order)!

Bob.

[Machines]

Ok I finally got round to buying a replacement. Got a 12AX7EH from eBay for £9 inc P&P. Shame that it's still the same problem.. looks like it wasn't the valve after all.

Have fired off an email to Ashdown.