Perfect Speaker for Current Source Amps?

NV&H · 22nd January 2006, 07:04 PM

With a true current source amplifier, would one not just need a single turn of wire on the speaker voice coil, albiet, a much thicker one?

If so, seems like inductance would (happily) vanish.

jan.didden · 22nd January 2006, 07:14 PM

Maybe yes, but you would also need an amp that could deliver extremely high current into a virtual short. Like an amp that could deliver +/- 100 amps @ 5V or something like that. Doable, not simple.

Jan Didden

mastertech · 22nd January 2006, 10:57 PM

100 amps hehe you guys got to be joking...

GRollins · 23rd January 2006, 01:18 AM

If you're in the business of designing the driver from the ground up, use niobium magnets or whatever is top-o'-the-walk these days. That would increase efficiency considerably over ceramic or Alnico magnets. Expensive, but necessary if you intend to give this a fair chance.
The planar drivers approach this. Each diaphragm has only a single, or sometimes double wire (also to include flat aluminum conductors) with what is for all intents and purposes a dedicated magnet. They're low resistance, and have virtually no inductance or capacitance.
The Magnepan direct drive ribbon accomplishes exactly what you're describing. It's a single linear conductor in a magnetic field...that's it. The resistance is on the order of 2 to 2.5 Ohms. Granted, there's no cone attached; the 'voice coil' is the cone, so to speak.

Grey

Nelson Pass · 23rd January 2006, 05:35 PM

Quote:

Originally posted by NV&H
With a true current source amplifier, would one not just need a single turn of wire on the speaker voice coil, albiet, a much thicker one?

If so, seems like inductance would (happily) vanish.

With a current source, the inductance of the voice coil vanishes
regardless.

MikeW · 23rd January 2006, 05:59 PM

The F1 drives the magnepan MMG much better than expected.

Nelson Pass · 23rd January 2006, 11:05 PM

Quote:

Originally posted by MikeW
The F1 drives the magnepan MMG much better than expected.

I expect that with the Maggies, the issue is mostly power.

Sandor · 25th January 2006, 08:18 PM

Do you think that the F1 can drive a pair of MMGs in my 13 x 16 feet living room? I experienced that a 300B tubed single ended (7-8 W) has not enough power. Or should I say that it has not enough CURRENT?
Now I drive my MMGs with a 300W/4 ohm solid state amp, but I am afraid that sometimes it clips (!!!).
Best regards.

Paul

Nelson Pass · 25th January 2006, 08:44 PM

The most dramatic case for a current source amp I have heard
is a Lowther DX55 in a sealed box and with a bit of loading
EQ. The differences were not at all subtle, more on the order
of night and day. As you move away from that type of driver
and box, the arguments for a current source become weaker,
and by the time you are running 85 dB woofers in a bass reflex,
you are probably better off with a voltage source.

Sandor · 25th January 2006, 08:57 PM

Nelson,
from the electrical an acoustical point of view, Magneplanar MMGs are more similar to the sealed boxes using lowthers, or to the bass reflex boxes? In other words: do you recommend littel power current source amps for maggies?
Best regards.

Paul

22nd January 2006, 07:04 PM	#1
NV&H diyAudio Member Join Date: Feb 2005 Location: Charlotte, North Carolina	Perfect Speaker for Current Source Amps? With a true current source amplifier, would one not just need a single turn of wire on the speaker voice coil, albiet, a much thicker one? If so, seems like inductance would (happily) vanish. __________________ NV&H

22nd January 2006, 07:14 PM	#2
jan.didden diyAudio Member Join Date: May 2002 Location: Great City of Turnhout, Belgium Blog Entries: 6	Maybe yes, but you would also need an amp that could deliver extremely high current into a virtual short. Like an amp that could deliver +/- 100 amps @ 5V or something like that. Doable, not simple. Jan Didden __________________ It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts - Sherlock Holmes Check out Linear Audio Vol 5!

23rd January 2006, 05:59 PM	#6
MikeW diyAudio Member Join Date: Sep 2002 Location: North of Boston	The F1 drives the magnepan MMG much better than expected. __________________ MikeW

25th January 2006, 08:18 PM	#8
Sandor diyAudio Member Join Date: Mar 2004 Location: Milan	F1 driving MMGs Do you think that the F1 can drive a pair of MMGs in my 13 x 16 feet living room? I experienced that a 300B tubed single ended (7-8 W) has not enough power. Or should I say that it has not enough CURRENT? Now I drive my MMGs with a 300W/4 ohm solid state amp, but I am afraid that sometimes it clips (!!!). Best regards. Paul

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22nd January 2006, 10:57 PM	#3
mastertech Banned Join Date: Mar 2005 Location: Australia	100 amps hehe you guys got to be joking...

23rd January 2006, 01:18 AM	#4
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	If you're in the business of designing the driver from the ground up, use niobium magnets or whatever is top-o'-the-walk these days. That would increase efficiency considerably over ceramic or Alnico magnets. Expensive, but necessary if you intend to give this a fair chance. The planar drivers approach this. Each diaphragm has only a single, or sometimes double wire (also to include flat aluminum conductors) with what is for all intents and purposes a dedicated magnet. They're low resistance, and have virtually no inductance or capacitance. The Magnepan direct drive ribbon accomplishes exactly what you're describing. It's a single linear conductor in a magnetic field...that's it. The resistance is on the order of 2 to 2.5 Ohms. Granted, there's no cone attached; the 'voice coil' is the cone, so to speak. Grey

25th January 2006, 08:44 PM	#9
Nelson Pass The one and only Join Date: Mar 2001	The most dramatic case for a current source amp I have heard is a Lowther DX55 in a sealed box and with a bit of loading EQ. The differences were not at all subtle, more on the order of night and day. As you move away from that type of driver and box, the arguments for a current source become weaker, and by the time you are running 85 dB woofers in a bass reflex, you are probably better off with a voltage source.

25th January 2006, 08:57 PM	#10
Sandor diyAudio Member Join Date: Mar 2004 Location: Milan	Nelson, from the electrical an acoustical point of view, Magneplanar MMGs are more similar to the sealed boxes using lowthers, or to the bass reflex boxes? In other words: do you recommend littel power current source amps for maggies? Best regards. Paul

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