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4 Ohm SFI Orthodynamic Drivers

post #1 of 11
11/26/11 at 3:16am
Thread Starter 

Will it be a good idea to build earphones with 4 Ohm SFI Orthodynamic Drivers and artificially increase their impedance with additional resistors connected in line with the driver?

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post #2 of 11
11/26/11 at 4:41am

no

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post #3 of 11
11/26/11 at 4:41am

it really is as simple as that =)

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post #4 of 11
11/26/11 at 5:26am
Thread Starter 

I asked that question cause I had no luck in finding a dealer that sells 32 or 120 ohm drivers and I looked all over the web. Anyone got any ideas where can I get a pair of those drivers?

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post #5 of 11
11/26/11 at 7:42am

Why not just use the 4ohm drivers? 

 

I WOULD experiment with series resistors, although not necessarily to compensate for an amp that cant drive the load properly (10mw into 4ohms, lol). Due tot he very flat impedance VS frequency response curve of most orthos, I'm not sure how much of a problem a resistor to compensate for an amp that cant drive the load properly will matter, but there may be some cool sound hanging out there anyways. 


Edited by nikongod - 11/26/11 at 7:54am
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post #6 of 11
11/26/11 at 8:56am

my post was only saying i wouldnt bother with the resistors, i dont see the point. if the amp cant drive them without the resistors, the resistors arent imo going to help

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post #7 of 11
11/26/11 at 9:35am
Thread Starter 

What power rating should the resistors have and what do you suggest that the final impedance (driver+resistor) should be?

Can it damage the amp?

What characteristics should I check in the drivers specs for them to fit for use as a headphone driver?


Edited by Hal Rockwell - 11/26/11 at 9:39am
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post #8 of 11
11/27/11 at 11:19pm

Part of the problem with the 4 ohm drivers is that they aren't bi-pole. If you try it, let me know how it goes, I'm interested myself how the drivers sound for headphone use. 

 

You could start out using a pair of resistors around 30 ohms, and test them out. 32 ohms seems a good place to start

 

1/4watt should be fine for testing. The amp will see the driver as x ohms, when you put resistor in series with driver (driver ohms + resistor ohms)

 

Jared


Edited by ilikepie116 - 11/27/11 at 11:22pm
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post #9 of 11
11/27/11 at 11:29pm
Thread Starter 

I also found 8 ohm drivers. How do I know if they're bi-polar?

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post #10 of 11
12/6/11 at 10:58pm

You will just have to check in the description, as far as I know. Though, I'm preetty sure that the only bipole SFIs are the 32 and 120ohm drivers

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post #11 of 11
12/7/11 at 9:32am
Could you guys point me to some reading material regarding driver impedance and amp wattage? I was expecting the 4 ohm drivers to be easier to drive than 32 ohms, but now im all backwards
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