I´m new, some questions

[inspector77]

Hello, I´d like to start my own DIY project, only for fun.....i have few questions, i hope you can help me

I´d like to make a lathe for embosing laquers in mono, so i suppose i need three main components.

1- A mono cutter head, i´d like to do myself....something like a presto 5c. (without feedback)
2- A Overhead, i will try to do myself too.
3- A turntable, i will to buy it. ( a technics 1200 mk2 or Staton str8-150? )

I will start with the cutter head......
i need to buy a horseshoe magnet .....What are the dimensions? how many Gauss? Alnico or Ferrita?
i need to make the coil.... what kind of wire ? How many ohms?
What are the dimensions (width, length and height) of a presto 5c cutterhead?

I think that is enough to start!!!!

Regards

[opcode66]

If you do a search on this site you will find answers to a number of these questions. A little research goes a long way. Good luck!

[inspector77]

Thanks opcode66! sometimes is very difficult to find answers because i don´t speak english

but i found some information:

The magnet is made from Alnico and the coil must be 8 ohm...


Regards

[opcode66]

Coils can be any number of different values. It really depends on a few factors. How much space you have, how much power your amp has, and how much excursion you expect to get when paired with your magnetics. There is no one correct answer with respect to the coils. I've been experimenting with a number of different coil values. For my particular setup 8 to 9 ohms seems to be best. But, your experience may be different. Have you looked at the videos I've posted here: http://lathetrolls.com/viewtopic.php?f=15&t=5250

There may be some very useful information for you. With respect to magnets, I'm using Neodymium Rare Earth magnets with great success. Horseshoe magnets are a bit out of date. And not hardly as powerful.

[inspector77]

Thank you very much, your answer has been very helpful.

regards

[opcode66]

Neumann coils measure 4.7 Ohms DC Resistance. Westrex 3D has 10 Ohms of resistance per coil. Older mono RCA cutterheads are 2.7 Ohms. Presto 1D is 500 Ohms. That gives you a spectrum.

Also, do take into consideration that DC Resistance is only one measurement of a coil. AC Impedance is the other. As you run audio through a coil, it will self induct and create an EM Field. It will also rise in temperature, which increases its DC Resistance as it is in use.

[inspector77]

Neumann coils measure 4.7 Ohms DC Resistance. Westrex 3D has 10 Ohms of resistance per coil. Older mono RCA cutterheads are 2.7 Ohms. Presto 1D is 500 Ohms. That gives you a spectrum.

Also, do take into consideration that DC Resistance is only one measurement of a coil. AC Impedance is the other. As you run audio through a coil, it will self induct and create an EM Field. It will also rise in temperature, which increases its DC Resistance as it is in use.

Thank you very much for your explanations, they are very didactical, I'm learning a lot!.
I am in the process of buying the materials, I think I found an Alnico horseshoe magnet that satisfies the conditions (power and meassures), I'm researching what kind of copper wire have to buy to make the coil.