Late 70's Silverface Twin Reverb.

[charveldan]

http://i433.photobucket.com/albums/qq60/charveldan/100_0263.jpg

http://i433.photobucket.com/albums/qq60/charveldan/100_0259.jpg

http://i433.photobucket.com/albums/qq60/charveldan/100_0260.jpg

Should i have a filter cap job done on my Twin? It looks & sounds fine.

[jamesrsmith]

the caps are inside the chassis. if it sounds good why worry?

[Blue Strat]

the caps are inside the chassis. if it sounds good why worry?

Because they're 30 years old and should be changed at least every 20 years.

When they go they can take out more expensive components.

Think of it as an oil change. You don't do it AFTER your engine seizes.

If nothing else, the bias supply cap(s) should be replaces. This $1 component can take out your power tubes (and if you're REALLY unlucky, your output transformer) when it fails.

[HipKitty]

I'll add that a good going over would be in order as well. Make sure ALL voltages are good, pots and jacks are clean and corrosion-free. And seriously consider replacing those Sovtek's out....

[HipKitty]

I just saw this...looks like there is significant rust on the output transformer...

[charveldan]

I know what the "hum balance" pot is, the other one says "output tubes matching" is that the bias trim pot?

[phsyconoodler]

No,that matches each 'pair' of tubes to the other pair.The two tubes on the left are a 'pair' and the other two are a 'pair'.
The tube matching pot is simply to 'balance' the current between the two pairs.It's exactly the same as many silverface amps balance control pot.They don't adjust the overall bias voltage at all.
It's actually a good idea,but needs to have a 'bias adjust' as well to facilitate using other brands of power tubes without changing the range resistor.

[Blue Strat]

I'll add that a good going over would be in order as well. Make sure ALL voltages are good, pots and jacks are clean and corrosion-free. And seriously consider replacing those Sovtek's out....

+1. ANy tech worth his salt doesn't just replace caps when he does a cap job...he does a complete checkout.

[davemccarthy707]

Get those caps outta there. Would you drive a 67 Camaro with the original rotted out bias ply tires on it?

[HipKitty]

+1. ANy tech worth his salt doesn't just replace caps when he does a cap job...he does a complete checkout.

You'd be surprised the stories I hear in my shop from clients that had been elsewhere....

[Blue Strat]

You'd be surprised the stories I hear in my shop from clients that had been elsewhere....

Well, I DID say "any tech worth his salt"..... ;)

[HipKitty]

Well, I DID say "any tech worth his salt"..... ;)


Word to that Mike!

[tmac]

I didn't see a pic of the filter caps, maybe they've been changed already?

[charveldan]

I didn't see a pic of the filter caps, maybe they've been changed already?All original.