Gazjam
29-11-2016, 18:01
300B SET amp owner, mines has 2x300B power tubes and 2xTungSol 5687 NOS signal valves.
Last week or so been hearing an intermittant rustle/crackling sound from one channel.
Bollocks thought I.
Didn't even want to CONSIDER it might have been one of the new 300Bs...
Swapped the signal valves about and (happily) the noise followed the valve to the other channel.
Have a few spare 5687 signal valves but was annoyed as the one that crackled was known to be the best sounding type and was quite hard to track down.
Might as well look at the valve, see if theres anything obviously wrong with it before I change it?
Nothing obvious, maybe a couple of the pins were slightly bent and being from the 1950's the pins were heavily oxidised, amost black.
Needlenose pliers to the bent pins and took some Deoxit to it.
Didn't really shift the oxidisation from the pin, but know it might increase contact so worth a try.
Nope, still a rustling valve. :(
All set to chuck it but having nothing to lose and being disappointed with the Deoxit, thought Id give one more thing a try, and this is where the fun began...
Autosol metal polish, http://www.halfords.com/motoring/car-cleaning/shampoo-polish-wax/autosol-metal-polish-75ml old toothbrush, cotton buds and a lot of elbow grease later I had a 1950s valve with pins that were chrome, not black with oxidation.
Carefully sprayed the pins with Swarfega "Jizer" degreaser http://www.halfords.com/motoring/engine-oils-fluids/engine-cleaner-degreaser/swarfega-jizer-degreaser-500ml let it sit for a couple of minutes to do its thing, rinsed the pins off with water and and dried them off.
Gleaming like a new pin. :)
After some additional air-dry time I put the valve back in the amp and switched on.
No more crackling valve, but more important an immediate and very noticable difference between the two channels in clarity, transparency and even volume.
Because Id restored the valve pins to new.
Did exactly thr same with the other signal valve and wow...both channels now the same and a lot better sounding than before.
Result!
Use NOS valves in your valve amp...?
Get the Autosol out!
Last week or so been hearing an intermittant rustle/crackling sound from one channel.
Bollocks thought I.
Didn't even want to CONSIDER it might have been one of the new 300Bs...
Swapped the signal valves about and (happily) the noise followed the valve to the other channel.
Have a few spare 5687 signal valves but was annoyed as the one that crackled was known to be the best sounding type and was quite hard to track down.
Might as well look at the valve, see if theres anything obviously wrong with it before I change it?
Nothing obvious, maybe a couple of the pins were slightly bent and being from the 1950's the pins were heavily oxidised, amost black.
Needlenose pliers to the bent pins and took some Deoxit to it.
Didn't really shift the oxidisation from the pin, but know it might increase contact so worth a try.
Nope, still a rustling valve. :(
All set to chuck it but having nothing to lose and being disappointed with the Deoxit, thought Id give one more thing a try, and this is where the fun began...
Autosol metal polish, http://www.halfords.com/motoring/car-cleaning/shampoo-polish-wax/autosol-metal-polish-75ml old toothbrush, cotton buds and a lot of elbow grease later I had a 1950s valve with pins that were chrome, not black with oxidation.
Carefully sprayed the pins with Swarfega "Jizer" degreaser http://www.halfords.com/motoring/engine-oils-fluids/engine-cleaner-degreaser/swarfega-jizer-degreaser-500ml let it sit for a couple of minutes to do its thing, rinsed the pins off with water and and dried them off.
Gleaming like a new pin. :)
After some additional air-dry time I put the valve back in the amp and switched on.
No more crackling valve, but more important an immediate and very noticable difference between the two channels in clarity, transparency and even volume.
Because Id restored the valve pins to new.
Did exactly thr same with the other signal valve and wow...both channels now the same and a lot better sounding than before.
Result!
Use NOS valves in your valve amp...?
Get the Autosol out!