Thread: VOX AC10 clone
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Old 9th Aug 2018, 12:25 pm   #17
retailer
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Join Date: May 2005
Location: Adelaide, South Australia
Posts: 541
Default Re: VOX AC10 clone

The amp is now 99% finished tolex, piping and grill cloth done and chassis mounted back into the cab just the front panel to do.

The Goodmans speaker is getting close to 60yrs old, it came out of a chuch hall PA cab and saw weekly use from around 1959-1960 until 2005 when it was scrapped and replaced with a new Mackie powered speaker. Old age, constant use and possibly insect attack has seen the edges of the cone become very thin and quite floppy/compliant, it was so thin that looking into the cab from behind I could see light coming through the edges of the cone in places. In addition the paper voice coil had shrunk just in the area between the cone and actual copper coil, the voice coil gap tolerances are quite tight so the coil rubbed on the pole piece when the cone was fully depressed, it will need a recone in the future.
In an effort to prolong the life of the speaker cone and with nothing to lose I removed the magnet assembly (held on with 4 bolts) and turned up a 1.75" mandrel/dolly with a very slight taper which I inserted into the voice coil this forced the shrunken portion of the voice coil out to it's original size, I then painted some diluted epoxy cement around the expanded section, which held it's shape once the epoxy had set and the mandrel removed.

For the cone I diluted some contact cement with MEK to the consistency of water and painted two coats around the cone edge, the first coat did soak in to some extent and the second just strengthened it. This stiffened it up quite a bit and hopefully has extended its life somewhat. Guitar speaker cones are almost all doped with some sort of pliable glue/rubber or whatever - I'm not sure what it is. There are a lot of different ideas out there on the net, contact cement came up quite a bit so this is what I tried, from experience getting it on your fingers it seems to retain a rubber type consistency once it has set.

For those interested here is a 5min sound clip - I managed to talk No. 1 son into putting it through its paces when he came over to pickup the amp. https://www.youtube.com/watch?v=WUQtsEAAWyM
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