I'm reconsidering an old idea, to use a typical turntable platter for a diy transcription disk player and placing a larger tray on top only when I want to play anything larger than 12". I do rather like the dots on the side of my SL-Q2 and understand they are for the quarts lock speed control. I wouldn't mind using a platter with a built in strobe disk and providing continuous power to a strobe with a prism even if it only serves for visual inspection. Looking at pictures, the Pioneer PNR-114 platter seems to have a nicer shallow slope and 4 sets of dots, I assume for the traditional 4 speeds. However, I also looked at the platter for the Technics SL-235, which also has 4 sets of dots, surprisingly though, the spacing seems different from the spacing on the Pioneer PNR-114 platter. I haven't seen any technical documents in the archive here about built in strobe based speed control, I suspect it was considered a trade secret when a new technology.
-I'm traveling so I can't examine my Technics at the moment.
-This site lists 4 types of speed control in the database menus; quarts locked, servo
controlled, electronic(sounds vague), and synchronous.
-If I'm not mistaken strobe disks are dependent on frequency rather than diameter.Ca) Questions
1) Do these rows of dots have a technical/common/trade name(s)?
2) Can the rows of dots on the side of a platter coupled to a strobe of the mains frequency be used as a traditional strobe disk?
3) Are rows of dots on the sides of platters used for any method other than quarts lock?
4) Are the rows different from one model to the next for any reason, if so why and how do they work?
5) If a platter has 4 rows is it safe to assume they represent each of the 4 traditional speeds, 16,33,45,78 R.P.M.
6) Theoretically could I remove the rubber strip with the rows of dots from two 12" platters and mount them back to back on a custom 20" platter, cutting to fit, to produce a Pathe capable platter with a working built in strobe disk?
-Most of my experience with strobes is either re-purposing the pumpkin 3 led light circuit, or with photography strobes, neither of which I suspect are anything like the continuous single bulb strobe circuits in turntables.
-I know camera strobe bulbs often require high voltage to operate and burn out quickly if repeatedly flashed at too fast of a rate.
-Some strobe lamps, aside of course from the lamps on studio strobes, seem to be non-standardized and perhaps hard to find replacements for when they eventually burn out.
-It has been explained somewhere on this site that the strobe light used for a strobe disk should ideally use the same voltage frequency as the turntable motor, not sure how this applies to dc, or spring and kerosene powered tables however, I digress.
-I have no experience with Arduino, I do however have recent experience with MS-DOS and soldering irons, and a variable(mechanical) timer relayCb) Questions:
The following are assuming I have no qualms about splicing an additional transformer in parallel to the turntable mains input, and devising a way to mount the new transformer internally. If I wanted to use a strobe bulb and prism salvaged from one turntable on a table of a different model for the purpose of using side dots as a traditional strobe disk...
1) If it had long leads and wasn't firmly attached to the table could a quarts lock strobe with prism be used to view a standard paper strobe disk? Could a "built in" strobe and prism designed for a speed control other than quarts lock be so used, if so which types of control?
2) What should I look for in the part chosen, aside from good price of course?
Is there anything that especially improves some lamps over their alternatives? For example should I limit my consideration to examples with an isolated driver board or a large heat sink, a specific type, shape, size, or voltage of bulb? What is the stuff that would make incorporating it without building/purchasing additional parts easier while permitting a long service life.
3) Do turntable strobe bulbs have a typical voltage/amp range?
4) Do they require anything more than a transformer for their power supply,(regulated power supply or blocking diodes perhaps) or any unique parts (smart programmed driver board as apposed to mechanical blinker relay) to function properly?
5) Does the angle of the strobe prism have to precisely or even closley match the angle of the side of the platter? As mentioned the pioneer has shallow slopes while the Technics looks nearly vertical.
6) Considering all factors (price, availability, longevity of vintage bulbs/parts, etc.) Should I be considering instead to simply use a prism off a turntable and a more common lamp with a focusing reflector, and a generic off the slow boat driver circuit, or simple home made circuit?
7) Was there ever a turntable with a green strobe.
8 ) Were some turntable prisms glass or quartz, or were all of them plastic/acrylic and similar?