Tweaks and Mods for the Lenco L-70 and Magnetic Tonearm

1) The turntable and tonearm were working well, but extended listening was a little disappointing as the system was sounding a little distant or sterile in the mid-range.  A little bit of testing with the SR-12 test record frequency sweeps identified a dip in frequency response in the 1200-2400 cycle range.  I managed to trace this to a resonance in the main arm/support pillar, and fixed that by drilling a hole in the outer support sheath, directly opposite to the tonearm mounting, installed a metal threaded insert, and machined a brass grub screw to tighten up the contact.  This removed the resonance and made the sound fuller, and the imaging more full bodied.  I had thought that the rather close tolerances between the inner and outer support pillar pieces would make this unnecessary, but I was wrong,

2) The tonearm is straight, while the tonearm lifter on the Lenco L-70 was designed for a bent arm design.  As a result, the arm lift just failed to lift the arm from the record when it was at the end of the runout grooves.  I really wanted to be able to use the armlift, so I cut a piece of 1/4 inch Lucite to match the size and curve of the existing lifter, and extended it about 1 inch past the end of the existing surface.  Then I glued this to the existing surface.  It just fits underneath the arm in playing position when the lifter is in its lowest position.  It lifts the arm a bit high in the up position, but I can live with this.

3) the turntable got a Christmas present from my brother, in the form of a set of tiptoe points in extremely hard steel.  These were mounted on my 2-bit footers (Canadian quarters), with a micro-bubble foam wrap underneath.  They are good looking and very effective.

4) I built an extension rack for my wall mounted shelves to hold the greater size and weight of the turntable, and it turned out very well, providing solid support for the turntable and total freedom from footfalls, and most acoustic feedback, although this is difficult in my small room at very high volume levels, with the Karlson speaker just inches away.  Excuse the mess around the turntable, I've been listening too much.

5) A final mod for the turntable was to modify a cover that my dad had made for me 35 years ago to fit around the height of the arm bits and wiring in the back corner of the plinth.  It protects the playing surface from most dust when I am away on business, and no dust gets a chance to settle, since I use it almost every day when I am home.