Knowledge

KV2 Refurb Project Part 2

This is the second installment following the progress rebuilding our KV2 ES system. Containing the very first production unit of the ES1.0, this system needed to be brought back to factory spec and cosmetic appearance. Having Stripped the ES1.8 subs in the first part of our blog, this part shows the ES2.5 and ES1.0  cabinets stripped back before we begin the re-build.

The next step for the KV2 restoration was the ES1.0 mid-highs. Compared to the ES1.8 subs, these were in much better condition. Not surprising as they have been in the air rather than the subs which had been on the floor of a venue for a very long time. Issues with them include rusty metalwork, poor exterior paint finish to the woodwork, several damaged bolts for the waveguide sections and internal damping material soaked in the remains of smoke machine fluid. The waveguide sections needed to be removed by taking all button head socket head bolts out. This allows the whole waveguide section including both 6.5″ and 1″ drivers to be removed in one go. Once the waveguide is out, the 12″ LF driver is revealed along with all of the smoke fluid soaked damping material.

Once all exterior components were removed from the ES1.0s, the insides were inspected. This revealed the fibreglass internal damping material was soaked in smoke machine fluid. This needed to be replaced, but the original pieces were carefully removed and retained to be used as templates for the new pieces to be cut from. Lastly the low mid drivers were taken out, leaving the cabinets bare apart from the connector plates, which wouldn’t come off without being damaged. As one of these boxes is the first ever production unit of the ES1.0, serial 000001, the serial number on the original connector plate is a significant part of this system and we thought that it was better to leave the plates in place and mask them off when it came to painting.

For the first installment of this project, visit: KV2 Rebuild Part 1

KV2 speaker during rebuild project
KV2 wave guide
inside a KV2 speaker box
KV2 speaker box on pallet

The ES2.5s were also stripped at this point. Slightly better than the ES1.8s, but still not in the best condition on the outside as they had spent some of their life on the floor too. None of the subs contain damping material, so it didn’t need to be replaced on either the ES1.8 or ES2.5 subs.

On the ES2.5s, there are eight corner handles to remove, the socket plates to take out plus the main front panel which contains part of the porting/driver loading arrangement and provides access to the drivers when removed. Despite being very careful removing the retaining bolts, two rounded out, so they had to be removed by drilling the heads out. A careful procedure to make sure that the bolt heads are removed without damaging the woodwork on the panel itself.

Once the ES2.5s handles, connector panels and front panels were removed, the 15” bass drivers could be removed and inspected. Amazingly after all this time, all of the drivers are in good visual condition and the suspension still feels like it should. No cones have yet proved particularly less firm than they should do, which, given that the damping material in the ES1.0 was soaked in smoke machine fluid, we were expecting to find some fairly soggy, soft cones.

KV2 driver

The grills for the ES1.0 were relatively rusty. Nowhere near as bad as the ES1.8 subs, but certainly needing to be stripped and repainted. They only cover the exit to the low mid horn section and are held in by a slot at one side of the box that they fit into and the waveguide section clamping it down at the other end of the grill. They should slide out easily, but needed a bit of encouragement with a small screwdriver as the years of grime had glued them in. Although for most of their lives, the ES1.0 have been in th eair, they have sustained some evidence of impacts, so the dents in the grills will be hammered out with a rubber hammer and possibly a short peice of 4×2, back to flat, before they are resprayed.

The grill on each ES2.5 is part of the front panel, so will need to be carefully cleaned and sprayed without damaging the rest of the ply which makes up the front panel. These along with the small round grills for the 6.5″ mid drivers are fine mesh, so are harder to clean successfully with abrasives, but a fine wire wheel on an angle grinder should suffice. All forteen grills for the three different types of speakers will be prepped and cleaned so they can be sprayed at the same time.

KV2 grill
KV2 speaker grill
rusty speaker grill from KV2

To try and make the boxes look as good as possible on the outside, the surface imperfections needed to be addressed. As with the ES1.8 subs that have already been stripped, these boxes also revealed various bits of damage to the outside. There were some holes where cable clips had been used to secure cabling in the previous installation as well as some scratches, scrapes and the odd dent here and there, plus a couple of holes, drilled into the boxes. Normally, in the course of sound system maintenance for a rental company’s hire stock, repainting speakers might be an annual process to keep them looking presentable. This would involve treating obvious large marks, but it wouldn’t be treated like fine furniture. Given that there aren’t any events until June 21st, this system is going to get a much more meticulous make over and will get far more detailed repair work than we would normally have time for.

Hole in a KV2 speaker box
Damage to a KV2 speaker box

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