ProJect RPM4 renovation
Copyright 2013 © Troels Gravesen

Having a ProJect RPM4 for sale I thought it would be fun to do a little tweaking before it appears on my sales page. The tonearm is actually very good and does well with my Dynavector XX2 mkII cartridge. The original platter had a crack, thus a new platter was made from 2 x 16 mm black MDF. The original plinth is the worst part being light-weight and resonant and compared to the new Baltic birch (4 x 15 mm + 4 mm bitumen pad) is night and day.
Having some 25 mm black MDF leftovers I made a sub-plinth and added sorbothane sheets in between. I mounted the original feet on the sub-plinth. All in all a more than decent entry-level turntable.

The original ProJect RPM4 turntable


The renovated RPM-4








Rebuilding


The plinth is the worst part of the original turntable. Light-weight and highly resonant. To the right the original platter on top of new platter.



New plinth shaping up. Made from 2 x 30 mm laminated Baltic birch with 4 mm bitumen pad in between.


Bottom view with routings for arm cable and power supply.


Left: Routing groove for on-off switch.
Right: The Lenco L75 matt doesn't work with the RPM4 platter. Matt must be max. 2 mm thick to allow proper functioning of the fastener.