The giant 'Refurbishing my Yamaha NS-1000M's' thread

[YNWaN]

I was discussing my whole refurbishment plans with a friend and he sugested I should take lots of pictures as I go along and post them. I don't usually bother with pictures and just get on and do it - but this time I have taken pictures .

So, yesterday I started the refurbishment. I should add that the intention here is not to inherantly alter the Yamaha design in any way, just to tidy it up.

First thing was to take everything out of the cabinets:

Taking out the mid and tweeter. The wiring is the original used by Yamaha; this has oxidised in parts and will be replaced.



Close up of the back of the tweeter. This shows it wired in reverse phase (+ wire to - terminal), this is the correct way.



Close up of the back of the mid driver. This is wired in positive phase, which is also correct. Note the enormous magnet assembly and the rear can making this a sealed unit.



The cabinet with bot mid and tweeter removed. The cabinet is screwed and glued chipboard with beech battens and plywood braces.



Close up of the mid removed. You can see where Yamaha have taken the cabinet cut out for the bass unit and screwed and glued it to the back of the cabinet for reinforcement. The picture also shows the extra cutouts to allow the cables to exit neatly from the drive unit.



Taking bass driver out (sorry it's a bit out of focus). This is also connected in positive phase. All drive units have case aluminium chassis.



Bass driver removed. You can partly see the horizontal plywood brace that is positioned between the bass driver and mid/tweeter section of the cabinet. There is also a vertical brace on the front panel between the mid/tweeter and adjustment pots.



Adjustment pots removed. You can see the copper shielding. These are going to be removed completely and replaced by fixed resistors. The holes will be filled in and laminated over.



Crossover removed (sorry again for this being in poor focus). This shows the replacement polypropylene capacitors tagged on to the original crossover. The old capacitors have just been electrically disconnected. This crossover is going to be binned and the pars are going to be moved to a custom built external
crossover.



Just starting to sand the surface of the cabinets and fill the little dents left by previous owners. Originally these speakers were black and somebody, in the past, has tried to sand them back to a wood finish (which hasn't really worked). I have also removed (they are screwed in place) and filled in the speaker grill mounting sockets. This is only the first round of filling - two more to go probably.



Trial templates new gaskets, made fromm 3mm acrylicfor, sitting in the laser cutter.



The trial gasket templates tried for fit in the cabinets (the real gaskets will be laser cut from 1mm neoprene sheet) - very pleased with this. The one for the adjustment pots isn't actually going to be used but the file will be used to cut out the blacking plates.



Blanking plate trial fit. Made from two 1.5mm layers of Aeroply that have been glued together and cut to size with the laser cutter. These will also have MDF plugs glued to the back of them and then glued and filled in to the cabinets.



Replacement badges I have made for the front of the speakers. The one on the left is made from violet tinted acrylic with the writing laser etched on the rear. The middle one is made from brushed aluminium and the one on the right is transparent acrylic.



More pictures on Monday...

[YNWaN]

Whoops, forgot a couple of pictures:

This is a trial of the replacement rear panel. The original is injection moulded ABS. The replacement will be 3mm laser cut and etched black acrylic glued to a combination of MDF and plywood. It is only in clear plastic here so I can check for fit and the big slot in the middle is so that it would slip over the wiring without disconnecting anything - it won't exist on the finished thing.



This shows the panel with the Neutrik SpeakOn sockets fitted. A four way for the mid and treble and a two way for the bass. A pair of 4mm out sockets are wired to the tweeter to allow a super tweeter to be easily added in the future (perhaps). 2mm thick colour coding plates in black and red have also been made for the sockets (from HIPS).



This an earlier CAD drawing of the rear panel (now updated).



This is a plan of the crossover layout. The circuit is the same as the original and so are the components values. The original coils will be used but the capacitors are to be replaced with polypropylene ones. This has been updated a bit recently - more pictures to followwhen I get to that bit.

[YNWaN]

On Monday I will make the final back panel and the face and rear plates for the external crossovers.

I will also finish and glue in place the blanking plates for the mid/tweeter adjustment pots, do some more filling and sanding of the cabinets in preparation for the laminate.

Photographs of the above to follow .

[flatpopely]

All looks superb! I'd be tempted to make the back panel out of clear acrylic.

[YNWaN]

Thanks mate .

The problems with making the back plate from clear acrylic are; a/when the drivers are fitted it will be completely dark inside the speaker - and even if it were lit there would be nothing to see as it's completely stuffed by glass fibre wadding (which is a rather uninspiring pale yellow) .

The back plate will be gloss black acrylic and bonded to layers of MDF and birch ply, so that when bolted in place (the current wood screws are being replaced with M4 machine bolts and T-nuts), it fills the panel hole to the same depth as the cabinet and is at least as stiff as the rest of the back panel. The acrylic is really more for aesthetics and to take the etching and attach the sockets to.

All the pictures are also viewable in a Flickr account I have created under the user name ynwan.

[flatpopely]

And another thing.

I would keep the pots in place, even if you by pass them internally. Unless you keep them for all eternity moving them on might prove tricky if they have been 'improved'.

[YNWaN]

Yes, I considered for a long time whether to keep the adjustment pots. In the end I have decided to delete them from the front but make the external crossover in such a way that they can be added to that if required and the fixed resistors can also be changed. I had designed acrylic blanking plates to replace the pots and also drawn up the required gaskets; that way they could always be reinstalled if required - perhaps I should just do that - what do you think?

[flatpopely]

Yes, keep the ability to reinstate the pots.

Great thread Mark, and a good idea to have loads of pics.

[YNWaN]

Cheers Andrew .

I've done quite a lot of planing and bought most of the stuff I need (cable, connectors, cases (though I was kindly given these), crossover components, screws, laminate, glue, gasket material etc.), but there is a lot left to do - I can't wait to get stuck back in to it .