I dropped a valve

[Andrew.S]

Hello Forum,

 

I was recently rolling my 6L6gc's with KT77's when I dropped one of the boxed up '77s on the carpet via a dumbell no less!

 

All seemed well, no breakage, but the valve developed a quiet crackle.

 

The plan is to replace the set of 4 but I'm a little worried that using the valve might expedite it's failure and do damage to the amp?

 

I know, I know, I should switch back to the 6L6gc's but I much prefer the '77s.

 

Or, does anyone know if I can get a single matched replacement in Sydney?

 

Appreciate any advice.

 

Cheers,

Andrew

[lovetube]

Hello Forum,

 

I was recently rolling my 6L6gc's with KT77's when I dropped one of the boxed up '77s on the carpet via a dumbell no less!

 

All seemed well, no breakage, but the valve developed a quiet crackle.

 

The plan is to replace the set of 4 but I'm a little worried that using the valve might expedite it's failure and do damage to the amp?

 

I know, I know, I should switch back to the 6L6gc's but I much prefer the '77s.

 

Or, does anyone know if I can get a single matched replacement in Sydney?

 

Appreciate any advice.

 

Cheers,

Andrew

replace the one that you droped.

Duc

[Guest Muon]

What amp is it?

 

Does a replacement really need to be matched? If not as Duc says replace the bad one.

 

If the do need to be matched, to match what you have you would need to know what levels the other three are tested at.

[Monkeyboi]

Just a thought.  Take a look at the pins on the base of the valve.  The crackling may be due to a dry or micro-fracture solder joint on one of the pins.  In which case it's repairable with a re-soldering of the pin.  If not, I'd be replacing the suspect valve with another KT77 from the same brand as the others.

 

To match valves you really need access to a valve tester and compare the transconductance of the proposed replacement with the other KT77 valves.  Sadly many so called "matched pairs" or matched quads" sold aren't all that well matched.  You may find just simply replacing the suspect KT77 with another KT77 from the same manufacturer may very well be adequate.  Let us now how you went.

 

Cheers,

Alan

[mackeb]

I honestly had to stop and think about the thread title - I had visions of major engine damage, holes in piston crowns etc.

 

Last transistor I dropped on the floor didn't break (sorry, couldn't help myself ;-)))

[Bronal]

+1 for what Monkeyboi says.  KT77s  walk all over 6L6GCs.

[Andrew.S]

Hi Guys,

 

Thanks for the responses. I can see how one could mistake valve in an engine for one in an Earle Weston Tranquility. 

 

I've had a look at the valve, Genalex Gold Lion, and given the pins a wiggle and they seem to be fine.

 

I'm going to go with the advice and buy a replacement.

 

What a butter fingered idiot I can be.

 

Cheers

[LogicprObe]

That's unlucky.

They're usually pretty robust.

 

I dropped a couple of GE 6550s............on the tiled laundry floor once..................unfortunately they smashed!.............and I'd only just got home after picking them up!