Vibro Champ cap oddity, or not?

[xFallen]

This is a 1964 BF VC.

I opened the amp up to finally install the three prong plug I have been meaning to do for the last 5 years. I think the PS cap needs replacing too but we'll see what happens with the new speaker in place. Now I am wondering about the paper caps though. Maybe this is normal, but it looks odd to me. Check out the "outgrowth" on the cap within the block box:



Is it a plug or something from the manufacturing process or indicative of damage to the cap? I had never noticed before...

This black burnt looking mark could be damage form a soldering iron I suppose, or maybe some smoke tried to get out.


Thoughts? Don't want to touch anything if I do not have to. The speaker is now pretty much completely gone so a Weber AlNiCo 8S is on the way.


Thanks,

Barry

[Richard]

I can't tell if that's leakage from the cap but after 43 years, they may be due for a replacement. They often last longer, but 10 years is often considered the standard service life.

[Enzo]

That is the guts of your cap oozing out its vent. Replace it. The burn mark on the paper cover is nothing.

By the way, that may be paper covered, but it is not a paper cap, it is an electrolytic. A paper cap would be either wax covered or in a molded package. Nowdays we use film caps where paper caps once were.

[xFallen]

That is the guts of your cap oozing out its vent. Replace it. The burn mark on the paper cover is nothing.

By the way, that may be paper covered, but it is not a paper cap, it is an electrolytic. A paper cap would be either wax covered or in a molded package. Nowdays we use film caps where paper caps once were.

Yes, paper covered but electrolytic.

Sounds like my suspicions are confirmed. Time to replace the caps. I think I will just do the electrolytics and leave the others.


Thanks,

Barry

[Dave Curtis, dB AudioTech]

Yes, paper covered but electrolytic.

Sounds like my suspicions are confirmed. Time to replace the caps. I think I will just do the electrolytics and leave the others.


Thanks,

Barry

Good call. Don't replace any of the small "signal" caps unless they're bad. Also, make sure you clip the line-to-ground "death" cap when you do the 3-wire cord.

Electrolytics: Higher voltage ratings are fine, but try to use the same capacitance. Richard's 10-year replacement is a mil-spec that I've run across. If they're more than 20 years old I advise the customer that they be replaced for reliability's sake. They might just run fine for another 10 or 20 years, but they also might fail and take out some very expensive components on their way out...

-DC

[xFallen]

Good call. Don't replace any of the small "signal" caps unless they're bad. Also, make sure you clip the line-to-ground "death" cap when you do the 3-wire cord.

Electrolytics: Higher voltage ratings are fine, but try to use the same capacitance. Richard's 10-year replacement is a mil-spec that I've run across. If they're more than 20 years old I advise the customer that they be replaced for reliability's sake. They might just run fine for another 10 or 20 years, but they also might fail and take out some very expensive components on their way out...

-DC

Yeah, the amp sounds decent otherwise. I see no present need to change any of the other caps in the signal chain. I guess I will know more once the other caps and speaker have been replaced and have had a chance to settle in.

Thanks for bringing up the death cap issue. I did indeed clip it, but did leave it inside the chassis away from any electrical connections for the sake of who knows what...maybe some future owner will want it for some reason. I don't plan to sell this instrument so it'll (hopefully) be a few years before that becomes an issue.

I just ordered the caps. The Weber should be here soon too. It'll be fun breaking everything in.


Barry

[xFallen]

Just to close the loop, my Weber Signature 8S arrived and I installed it late this week. It sounded good but clearly needs some break-in time. I went ahead and ordered a can cap from AES as well as the appropriate electrolytics (Sprague Atoms). They came in today's mail so I installed them too.

What a difference. With the amp on, volume turned down, and nothing plugged into the amp inputs, you cannot tell the amp is running even from a foot away except for the glow of the jewel lamp. Dime the volume and there is a barely audible hiss. Amazingly quiet all around.

I couldn't play the guitar through it too much or very loud because the wife is napping. But the bottom end (of the AMP, you wankers) is very tight and single plucked notes are very articulate. Can't wait for the speaker to break in and it will be fun working through the hours doing that in the meantime.


Barry.