Cap job on Vibrosonic - pictorial. Update jun5.

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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Orang Goreng » Sun Jun 06, 2010 11:31 pm

Sure. Don't we have one already?
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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by sookwinder » Mon Jun 07, 2010 12:20 am

Doc, yeah we already have cap jpbs in the library, but I don't think there is one that shows the amps that you've worked on.... remember a picture is worth a 1000 (what ever they are) and have a few pics with some good words, on that type of amp may well encourage others....
relaxing alternative to doing actual work ...

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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Orang Goreng » Mon Jun 07, 2010 12:34 am

Truedat, plus it works the same on all 70s 100W models. OK, I'll shuffle it around a bit and re-post there.
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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Orang Goreng » Mon Jun 07, 2010 11:58 am

So you know how most of these chassis are suspended by impossibly long bolts which anchor in a nut only accessible through the inside of the cabinet? I don't know if it's just me, but for some reason I always lose grip on a specific one (the one near the pilot light), which then invariably gets stuck between the baffle and the bottom of the chassis. You'd imagine it comes out when you put the chassis back in, but no. Through mystical forces of nature (well, I put the chassis in with the cab face-down, so it's mostly gravity) the nut remains upright and gets trapped when the chassis is returned. I forgot about that and put the other amp's chassis in this cab. This one uses a more clever, later suspension system, so I didn't realise the nut (now needed with the other amp) was still trapped.

So I removed the grille to be able to get to it.

Right.

So one reason why I wanted to service this amp is that at the last gig, it had a strange buzz, which got progressively worse during the night (it was the backline guitar amp of the evening, so it was in use for several hours). Buzes in unsewrviced old tube amps scare me, so I wasn't going to use it until I'd serviced the Dangerous Bits.

Well, I guess I now found the reason for the buzz ;).

Image

Right. I don't notice anything odd when I play at room volume now, but yeah, I can imagine this buzzing at gig/jam session volume; it did sound somewhat mechanical but I could find something that was loose enough to vibrate at the time. Didn't think of looking here.... The chip was lying at the bottom of the cleft between baffle and grill.

Right. So I know it's a dust cap and mainly serves as just that, but also contributes to that "hi-fi" treble of the D130F. I know it's technically possible to just replace them. Is that an easy thing to do, given how they're glued to the cone? Is there a serious consequence to leaving this untouched given how this amp won;t be used for gigs for at least a few months? I have an intact one I could at least in principle cannibalise from my older, broken speaker. Is this where the elusive Black Goop comes in? And, given how the stuff isn't available in Europe AFAIK, do we know an Euro equivalent? Is there perhaps a solid ghetto fix? I can probably live with losing some of those trebles, really ;).


Many questions, once again.
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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Orang Goreng » Mon Jun 07, 2010 12:05 pm

Right, when I'm not busy fucking up other people's threads, I fuck up my own ;D. Show some love for the windows clipboard. Memories you thought you'd lost in Pat's The Wall thread.

Image

Doketer Bibber would be a very feasible explanation for buzz. It shouldn't get much weirder. Away from the internet. Now.
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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Stratelejazzuar » Mon Jun 07, 2010 1:04 pm

lol, the game "Operation"! :D When i was young, a friend had that game; it was so annoying i think i only tried playing once. looking up the original box/packaging for that game... ???

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is it just me or does it look like the nurse boy on the left has a crush on the doctor's rear? and said doctor (at a glance) seems to be performing on that red-nosed gentleman's parts. Doctor #2 seems rather devious, and why is the little nurse girl playing with his apple?!?! :wtf: :wtf:

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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Orang Goreng » Mon Jun 07, 2010 2:24 pm

Stratelejazzuar wrote:lol, the game "Operation"!
Yeah, from here: http://www.offsetguitars.com/forums/vie ... ad#p565218" onclick="window.open(this.href);return false;. I still had the link in my clipboard. But it seemed oddly appropriate.
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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by øøøøøøø » Mon Jun 07, 2010 6:10 pm

Man, that is weird. Not sure I've seen a dust cap break in exactly that way before! :D

In the meantime, take a piece of masking tape or blue painter's tape or some other easy-to-remove tape, and tape over the hole. That will keep the dust from getting in the voice coil gap.

You can certainly replace that dust cap. That is indeed where the "black goop" comes in. What you do is to use an Xacto blade or some other hobby knife to carefully cut around the dust cap as closely as you can to the edge. BE CAREFUL not to cut the cone. If you want, you can start at your existing hole, and cut an "X" pattern and peel back the 4 sections and cut them from the inside. In any case, you don't have to get too fanatical about cutting too close to the cone. If it leaves a little 'ridge' of aluminum and glue that's perfectly OK. You don't want to leave enough to significantly change the mass, of course, but a tiny little rim will have no real effect.

They make a replacement cap that is ever-so-slightly larger in diameter than the old one, and will cover the "ridge" left by the old one with little/no change in performance. It's here:

http://www.soundspeakerrepair.com/speak ... Dust+Caps/" onclick="window.open(this.href);return false;

You just apply glue to the ridge left from the old one and glue the new one on. Turn the speaker on its back and get a socket from a ratchet/wrench set to use as a weight to hold it down while drying. You're done!

If you really wanted to lose some of the treble, you could always just get a regular 4" paper dust cap from anywhere. The procedure is the same.

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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Orang Goreng » Tue Jun 08, 2010 2:06 am

øøøøøøø wrote:Man, that is weird. Not sure I've seen a dust cap break in exactly that way before! :D
LIke most of them, it was a bit dented to begin with. Those things must be under a lot of stress from the cone moving.
In the meantime, take a piece of masking tape or blue painter's tape or some other easy-to-remove tape, and tape over the hole. That will keep the dust from getting in the voice coil gap.
Ah cool, will do.
You can certainly replace that dust cap. That is indeed where the "black goop" comes in. What you do is to use an Xacto blade or some other hobby knife to carefully cut around the dust cap as closely as you can to the edge. BE CAREFUL not to cut the cone.
I knew those years of microsurgery training would come in handy even after quitting research! ;D. Thanks, I feel confident again.

Does anyone know what makes up Black Goop? Funnily enough, I was having lunch with some field biologists some time ago. One of them was an American guest researcher, and she actually had a minor problem... she used the Black Goop in a research setting, fixing shit to other shit. Not available here anywhere!

I do know there's some speaker repair companies around, I'm sure they'll know an alternative. But if any fellow Europeans have good experience with a local equivalent, I'm all ears :).
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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by øøøøøøø » Tue Jun 08, 2010 5:33 am

Any speaker adhesive will do just fine. Should you order the dust cap from the site I linked to above, add this to your cart:

http://www.soundspeakerrepair.com/speak ... Adhesives/" onclick="window.open(this.href);return false;

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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by øøøøøøø » Tue Jun 08, 2010 5:34 am

P.S., your buzzing was probably the broken-off piece being bounced around between the cone and the grille!

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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Stratelejazzuar » Tue Jun 08, 2010 5:38 am

øøøøøøø wrote:P.S., your buzzing was probably the broken-off piece being bounced around between the cone and the grille!
heh this buzzing reminds me of how my buddy's TRRI was buzzing - we laid the amp on the floor, took the speaker out that we thought was buzzing, checked it all over, etc. the buzz was gone once we put it back together. then it came back a couple days later... turns out the tilt back leg was vibrating against some other piece of metal and making the noise! ;D ::)

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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Orang Goreng » Tue Jun 08, 2010 6:58 am

øøøøøøø wrote:P.S., your buzzing was probably the broken-off piece being bounced around between the cone and the grille!
There's quite some room between the cone and the grille on a Vibrosonic... I wonder if perhaps it was simply stuck in the dust cap hole..
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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by Orang Goreng » Sat Jun 19, 2010 7:05 am

Bleeh, now all of a sudden my reverb stopped working. Never a normal day....
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Re: Cap job on Vibrosonic - pictorial. Update jun5.

Post by andy_tchp » Sat Jun 19, 2010 5:39 pm

Orang Goreng wrote:Bleeh, now all of a sudden my reverb stopped working. Never a normal day....
Sorry to hear that mate. It's not been a good week for OSG Vibrosonic Reverbs eh? :(
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