DC Coupling for MC Cartridges - how much error voltage before coil damaging

[tiefbassuebertr]

Originally Posted by jcarr

The most extreme of the Matsudaira-designed MCs (MySonic Labs) use 60um wire for an internal impedance of 0.6ohms.
hth, jonathan carr

Very interesting - and new for me.

Do you mean the model "Eminent" ? - describted about the weblinks
http://www.soundscapehifi.com/mysoniclab.htm
http://www.analog-audio-connection.d...inent_Info.pdf
http://www.high-end.ch/p_analog/tonz...onic_Flyer.pdf

By the way - what kind of DC protection solution for the moving coils of cartridges are inside in your RIAA phono preamp models?

[x-pro]

Originally Posted by tiefbassuebertr

By the way - what kind of DC protection solution for the moving coils of cartridges are inside in your RIAA phono preamp models?

In my current design there is no such protection (it is not required) and there is no input capacitor (it is also not required), as it is a straight FET input with no DC current to speak of.

Alex

[jcarr]

Originally Posted by tiefbassuebertr

Do you mean the model "Eminent"?

No, My Sonic Lab Ultra Eminent BC. Link below:

Ultra Eminent BC

Originally Posted by tiefbassuebertr

What kind of DC protection solution for the moving coils of cartridges are inside in your RIAA phono preamp models?

Same as Alex. JFET inputs, no capacitors, DC servo.

hth, jonathan carr

[Steve Dunlap]

In MC cartridges, the range of coil wire used will be between 12um and 60um. 12um is very seldom used, as it tends to break too readily in production. 15um was used by some medium-to-high impedance Denon cartridges. For low-impedance MCs, 30~40um wire will be more typical (35~40um in my case). The most extreme of the Matsudaira-designed MCs (MySonic Labs) use 60um wire for an internal impedance of 0.6ohms.

Thank you for that information. That would mean a safe continuous current would be (for 35~40um) about 2ma. Fusing current would be higher. I would think even a poorly designed BP phono stage should have no more than one tenth that amount.

[oshifis]

Right, the Dynavector has 12 um coil (about 56 AWG). I don't know the number of turns, but it is low impedance.