CORRECTING THE AT PROTRACTOR

Took some time to correct the spindle hole size on the AT LP5 cartridge protractor provided (post 85). The too large hole = loosely fitting protractor on TT, simply pissed me off for what is an otherwise ok cardboard tool. Initially thought I could get away fixing this thing easily using adhesive looseleaf reinforcements for binders (1rst pic). Well, the center hole on these is too small at 5-6 mm dia. for a 7 mm spindle, plus didn't really want to do another tedious scalpel job to enlarge those holes: enlarging some to decrease another...

Last resort idea was to put the protractor on the TT then carefully and equally share the loose all around the spindle, followed by covering the loose spaces around the spindle with small pieces of masking tape, doing that on both sides of protractor. Not sexy looking, but it does the job. The result is a 7 mm hole and a now quite usable AT protractor (2nd pic). I double-checked the results I got with it VS two other protractors (Shure's & Stevenson's) and they match. Despite that, most of the time I still use two protractors when adjusting a cartridge to compare/confirm results. Then the cart should be performing at its best.

PHONO CARTRIDGE OVERHANG ADJUSTER

The white plastic "L" shape cartridge overhang adjuster, seen on posts # 88 in the box and # 87 with the 408 cart/shell mounted on it, is the one from the old Technics SLQ2 gone to recycling. Because it holds the shell/cart in place while working on it I still use that adjuster for INITIAL cart setup on shell. This reduces handling of the fragile cart/shell/tonearm directly on the TT, therefore minimizing risks of an accident.

That small tool (3rd pic) remains relevant here, saves some time and potential needle damage. I noted some guys sell their overhang gauge on E-Bay, same for their Technics clear box SH-98 cart holder previously shown.That adjuster, with 52 mm effective length, is for a 15mm overhang. The last three TTs purchased (SLQ2, LP120 & LP5) required needle overhang adjustments of 15, 16 and 17 mm respectively. So I start with the 15 mm setting indicated on the tip (4th pic), then add just a bit more for 16 or 17 mm as the case may be. Checking the cart is parallel to the headshell is also simple using the overhang adjuster: comparing cart's front line vs shell's front line for example.

Note at the bottom of the second pic here, AT indicates "Perfect Overhang Settings, OK"circled. What is shown there is NOT overhang setting but rather making the cart parallel to the headshell. Overhang is a distance of where the needle should be located for lower distortion, represented on the protractor by the two black dots inside the lines shown.

My initial settings with the overhang adjuster are about 90-95% correct for 16/17 mm, therefore only minuscule fine tuning is left to do with the cart/shell in the tonearm & protractor sitting on the TT. Most of the work being already done using the overhang adjuster, prior to moving to the turntable for final adjustment, the latter is a breeze with much less handling to do directly on the TT. The last cart pre-adjusted needed less than a parallel line further adjustment based on the protractors. Did that, done deal!

Richard


Name:  IMG_0811.jpg
Views: 201
Size:  69.0 KBName:  IMG_0818.jpg
Views: 200
Size:  74.0 KBName:  IMG_0826.jpg
Views: 202
Size:  56.7 KBName:  IMG_0816.jpg
Views: 204
Size:  44.7 KB