Bogdan AH
New Member
Right. By the way, I gave a try to the Rega P3... you can see what happened here : http://audiokarma.org/forums/index.php?threads/rega-owners-thread.371230/page-17#post-11916549
Tesla NC 430, or How I live now. MK2
Right. By the way, I gave a try to the Rega P3... you can see what happened here : http://audiokarma.org/forums/index.php?threads/rega-owners-thread.371230/page-17#post-11916549
Make some measurements of the arm, go to the overhang calculator at VE (presuming that given the seeming length of the arm it is probably designed around 15mm) and calculate a set of null points for that specific arm. Then print off the Chpratz protractor and use the numbers you've generated. Standard protractors don't work for every arm necessarily. I just yesterday followed the process I have suggested in trying a new set-up for my 12" Audiocraft arm and I got far better results than with any standard protractor.
Solist
Active Member
So if I understand the process, going for the maximum allowed overhang and then use those numbers as the null points? It could be also done with the CH protractor program although it will be a pain in the b*** to get those numbers out.
What about when you have a separate tonearm, so you can change the STP distance and consequently change the overhang value?
You got me really curious about this method, never tried it.
What about when you have a separate tonearm, so you can change the STP distance and consequently change the overhang value?
You got me really curious about this method, never tried it.
No, not the maximum allowed overhang, not at all. The point is to find out what is optimum and gives the lowest distortion.
With the arm I was working with (Audiocraft AC-400C) the numbers were all available in the cartridge database at VE. Now, the point to the overhang calculator is to generate a "best" set of null points relative to a supposedly "known" set by trying alternate overhang values. Things is, you don't have a "known" set of anything. So, start with something probably for an arm of about that length (circa 9" I presume so frequently 15mm). You can easily measure spindle to pivot and work out something reasonable for effective length just by taking measurements. Offset angle is likely to be 21-22º for an arm of that length. Plug in the same value for Overhang and New Overhang and it will generate a set of null points for you and then below that will show Maximum Distortion and RMS Distortion. Record those values and then go back and try some other near values for the New Overhang slot and see what you get.
I had been using my usual (Baerwald) protractor to align and was noting some distortion on the outer track. Baerwald was just not the right pattern for the arm. I generated a new pair of null points, printed off the CHpratz protractor and got some very real improvement - nice even, low distortion the whole way through. Unless you're using an arm with a SME type base (where alignment is done entirely on that basis) one cannot just change the spindle to pivot length without making a new arm board, nor can I really see why one would want to mess with the geometry in that way.
Even if you decide to generate a specific protractor for the arm I would still recommend taking the raw measurements off the arm and then plugging them into the calculator. I found it to be super educational!
Bogdan AH
New Member
Interesting informations both in quantity and quality ! Thanks ! By the end of this month I will recover my Technics SL1100, SME 3009 and IKEDA 407 (and hopefully my laser printer also), and I believe that all this will come in very handy then !
By the way, a quick question out of topic. In a second hand shop near me, there are a Sansui SR 2050 with original cartridge and a Micro Seiki DD25 with a new AT 91, at 200 Euros each. Cosmetically they look well but I feel that this is quite overpriced... What would you say ?
By the way, a quick question out of topic. In a second hand shop near me, there are a Sansui SR 2050 with original cartridge and a Micro Seiki DD25 with a new AT 91, at 200 Euros each. Cosmetically they look well but I feel that this is quite overpriced... What would you say ?
Monetary questions are supposed to go in "Dollars and Sense" rather than topic threads, but..... Not sure about either table as I've no personal experience. In Canadian dollars it seems a bit high, but prices have gone loopy in recent times and I can't keep up!