I'm reparing a 70's silver face Champ for a friend. Dead mains transformer. It arrived with the valves out and the 5Y3 has it's locating spigot snapped off. I'm wondering if it was put in the wrong way round and maybe killed the transformer, or could be coincidence and the spigot broke after the transformer event. I can put it in my valve tester and find out but even if it's working it's probably not great to give him the amp back with a mechanically faulty valve that could end up in the wrong orientation.
He's on a limited budget and won't be shelling out for a vintage NOS 5Y3. I don't have any spare so what's the best of the currently available new replacements?
Comments
If you really don’t want to use it, just buy an old-production one - they’re not expensive, and any is better than any new one.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
If it does need replacing, I would fit the new one with a proper clamp, and cut away whatever you need to in order to fit it. DO NOT use a Dremel or similar on any of the old solder though, without at least wearing a proper dust mask - it creates fine lead dust which is extremely toxic if inhaled, even in tiny quantities.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
Rift Amplification
Brackley, Northamptonshire
www.riftamps.co.uk
You should not run an amp with the *preamp* valves out, exactly since that will stop the current draw and mean that the lower stages of the B+ chain rise to the full HT, which puts a lot more stress on the filter caps than they've been used to, which can make them fail.
Running with the *power* valves out is fine.
Buckling means nothing, but they do very commonly develop leakage. In fact, it's quite often the underlayer which causes the trouble, and it can be fixed by inserting another cardboard spacer between the two - Cornflake packets are ideal .
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
I've also replaced a couple, but I've never even tried to solder the new one to the chassis - just cut the old one away, using an old wood chisel, which will chop through solder and aluminium with no trouble at all (just don't use one of your nice ones ) - then fitted a clamp.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
Rift Amplification
Brackley, Northamptonshire
www.riftamps.co.uk
That's interesting, thank you. Not heard of the Bronco. This one is the basic Champ, no tremolo and apart from the dead mains transformer I've replaced it looks untouched since being built ('74).
I've had a few Champs with failed can caps, and as there is enough space in the chassis you can fit modern electrolytics on a piece of tag strip.
In my experience can caps do seem more durable than regular caps; I expect due to greater thermal mass, and hence they don't get as hot.
NOS 5Y3s can be found cheaper than current production.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein