I recapped my bassman,and before powering it up I want to put it through a light bulb current limiter in case something is not right. I use a 240v to 120v step down transformer for the bassman.

When I use the light bulb limiter with my 240v amp (no step down needed) It works fine. (I connect the amp to the bulb limiter and turn on the main switch. The limiter glows slightly. I Switch the amp from standby to ON. The limiter will flash a little then return to a dull glow. I set the switch to ‘full’ and the light bulb turns off. No problem.)

The problem I have is when I plug in the step down transformer into it. The light bulb comes on straight away. Then if I set the switch to ‘full’, it blows a fuse. Is this because the step down,is drawing more current than the fuse on the limiter? The limiters fuse is 1.5amps.The step down say 5a.

I really don’t want to power up the newly caped amp without precautions… Any advice? Thanks.

The limiter should be plugged into the step down which is then plugged into the wall,so the limiter ends up between the step down and the amp under test.

Sheesh!

I thought that this thread was about some kind of kinky sex ...

(Tranny?)

Well, here is another lightbulb for ya!

What?

Stokes,so I would need to have limiter with a 120v input socket.like this?:

So:amp into limiter limiter into stepdow. stepdown into wall socket.

Yes or buy a Variac

Chet, sexy bulb!

Ahhh Kendrick. All sorts of wonderful stuff you can buy from Mr. Weber.

Yes or buy a Variac

I endorse this statement.

I was going to ask where you guys come up with these peculiar ideas, but then I saw the Kendrick photo. If you're really worried that you wired it wrong, a fuse is a great current limiter. If you want to be extra safe, start out with a smaller fuse. It's not generally recommended to Variac new caps, unless you know they've been on the shelf for a long, long time. It's also not recommended that you Variac a cap more than three times in it's lifetime. I've known some people to get carried away with a new Variac. BTW, Variac was the brand name for the General Radio "variable AC" auto-transformer. Over the years, it's become a generic name, like Skill saw or Crescent wrench.

is the proper skinning of filtercaps really necessary anymore. There seem to be arguments from the old guys for slowly ramping up voltage to form the dielectric and younger builders say it doesnt matter.

I'd love to hear Billy's side of this.

Billy,I'm quite sure I wired it correctly ,but I was advised to use a limiter as a precaution. Sounds like a sensible thing to do. Now are you saying if something is not right the fuse in the amp will prevent anything from blowing up? Safe as using the limiter?

Also, if I use the limiter I have, I would need to use a USA to AUST socket adaptor for the amp to go into the limiter, and an IEC to USA male to go into the stepdown.

Are there any issues doing this?? Light bulb?120volt light bulb? The guy who built it put a 1.5 amp fuse in the full power circuit in case someone has neglected to fit a fuse in the primary of the device being tested. Cheers.

Thanks.

>Now are you saying if something is not right the fuse >in the amp will prevent anything from blowing up?
That's what the fuse is for.

http://www.illinoiscapacitor.com/tech-center/papers.aspx

"Aluminum electrolytic capacitors can be given a one time reconditioning if they have drifted out of specification.

Equipment required: • DC power supply ( adjustable if possible) • Volt meter • Ik? resistor • Timer

Reconditioning also called voltage treatment consists of applying the rated voltage of the capacitor for thirty minutes through a 1k? resistor. When using an adjustable power supply initially apply 1?2 the rated voltage to the capacitor for 10 minutes then slowly increase the voltage to the rated voltage of the capacitor for leave at the rated voltage for 20 minutes."

I have more extensive tech notes at my shop.
I'll scan some of the info and post it here. If you use the resistor, use a big 5 or 10 watt power resistor and don't burn your fingers.
Sprague and Mallory used to have great tech notes, but now both of those names are owned by Vishay and Vishay is too big to bother with being helpful. BZ

Here's some helpful info for replacing filter caps. It's good to use higher voltage caps if practical. You don't have to match the original voltage rating. Caps are usually smaller now.

From Illinois Cap:
"Reducing the amount of voltage applied to the capacitor can also increase the expected life of the capacitor. The expected life can be increased by the ratio of applied voltage to rated voltage for the capacitor."

Ok forget the bulb and rely on the fuse.

I need to wire a 3 prong ac cord.(bassman 6g6b) Is it best to bypass the ground switch with the so called 'death cap'? Or does it not matter? Thanks.

Where are you? Are you running on 240 volts through a step-down transformer?
BZ

I'm in Australia. The amp has the original 120v transformer. I run it through 240 to 120 step down. The 2 prong plug is original and looks ridiculously dangerous. Thanks.

Sorry Mrock,I havent been able to log in.Yes,your limiter has to go between the power source,in this case your step-down tranny and the amp under test.This isnt the best way to form caps but is better than not doing it at all.A variac or the resistor method BZ is alluding to are much better.There are many arguments for and against pre-forming new caps these days,but the funny thing is,I have yet to hear an argument against doing it that makes any sense.Just because so and so says "it isnt necessary" isnt a viable argument.Techs and engineers have been doing it for decades,I learned that way a long time ago,and it makes sense to do it for no other reason than "to be sure".Using a smaller fuse is stupid.If the fuse blows,did it blow because you have a short or because the fuse is too small to take the inrush of current when the caps charge up for the first time?Change the fuse,it blows again,now you have to troubleshoot,get out the limiter,oh damn,I should have used that to begin with.You should change the power cord.Just replace with the proper 3 prong,the ground goes to the chassis near the higher current grounds usually near the PT bolt.Forget the old ground switch,dont need it anymore. "Aluminum electrolytic capacitors can be given a one time reconditioning if they have drifted out of specification." That statement applies to old caps that should probably be replaced anyway.Caps in a circuit with a "delayed" tube rectifier are subjected to a "slow ramp up" each time the amp is powered on.

Thanks stokes. Can someone take a look at this diagram I put together. I'm not comvinced I got the fuse section right.

Doesnt look right to me mrock.the switch should be between one wall outlet lead and one transformer lead and the fuse should be between the other wall outlet lead and the other transformer lead

Have you got a wiring diagram of some sort? Thanks.

I cant post one anyway.Just go to schematicheaven.com and look at almost any schem,look at the Fender Pro Reverb AA165,just one of many examples there,but at least you have a point of reference.You will see an old 2 wire ac plug type diagram,just ignore the "ground switch" and imagine the 3rd wire to ground.It is showing the fuse and switch as it should be in your case.

As generic as Kleenex or Scotch tape!

Another thread hijack ...

Hey Chris! ... where ya been?

Well, I haven't been here as much as I used to be either ...

Can ya make it to Balt.?

Ok so like this:

I think this thread was already hijacked.
BZ

That looks good,mrock