Building this one is high on my list but it is a complex one.
I have build an active 3-way speaker using 10W class A current drive amps (from Electronics World & Wireless World). Sounds good, but if it is better then normal voltage drive is another question. I looks as they are difficult to get stable. I had oscillations all over the place (60kHz up to 1.6MHz).
Problems are: you have to go active, you lose all damping of the woofer so you need active correction.
If you want to try, the EW&WW amp is much simpler (read: cheaper) and has some scope for experiments. Let me know if you are interested, I'll search the reference.
I have build an active 3-way speaker using 10W class A current drive amps (from Electronics World & Wireless World). Sounds good, but if it is better then normal voltage drive is another question. I looks as they are difficult to get stable. I had oscillations all over the place (60kHz up to 1.6MHz).
Problems are: you have to go active, you lose all damping of the woofer so you need active correction.
If you want to try, the EW&WW amp is much simpler (read: cheaper) and has some scope for experiments. Let me know if you are interested, I'll search the reference.
You may find the following articles of interest, unfortunatly they aren't available on-line:
DISTORTION REDUCTION IN MOVING-COIL LOUDSPEAKER SYSTEMS USING CURRENT-DRIVE TECHNOLOGY,
Mills, P.G.L., Hawksford, M.O.J.,
JAES, vol.37, no.3, pp.129-148, March 1989
TRANSCONDUCTANCE POWER AMPLIFIER SYSTEMS FOR CURRENT-DRIVEN LOUDSPEAKERS,
Mills, P.G.L., Hawksford, M.O.J.,
JAES, vol.37, no.10, pp.809- 822, October 1989
regards
James
DISTORTION REDUCTION IN MOVING-COIL LOUDSPEAKER SYSTEMS USING CURRENT-DRIVE TECHNOLOGY,
Mills, P.G.L., Hawksford, M.O.J.,
JAES, vol.37, no.3, pp.129-148, March 1989
TRANSCONDUCTANCE POWER AMPLIFIER SYSTEMS FOR CURRENT-DRIVEN LOUDSPEAKERS,
Mills, P.G.L., Hawksford, M.O.J.,
JAES, vol.37, no.10, pp.809- 822, October 1989
regards
James
Sorry Alex, I found the article but there is no date on it. Most I can say of it is that is from before 1996 (then I made my pcb), is called "Transconductance amplifiers" by K. Lewis p580-582 in Electronics& Wireless World.
I'll try to mail you a scanned copy, as the file is to large for an attachement to this forum.
I'll try to mail you a scanned copy, as the file is to large for an attachement to this forum.
Well, the flat response is only a problem if go down in frequency. Because of the output impedance >10k there is no damping. For a good midrange or tweeter, this isn't a problem. And if you do some active correction, you can get a woofer also under control, but then the question is if it is still current driven.
Nelson Pass said:
That's the badger!
Good call NP.
Havoc said:
I actually experimented some a couple of years ago, using the danish High Fidelity article as inspiration. It sounded really well. But for other reasons i never finished the project.
Anyway: I might be interested so Havoc - if you have a link to the EW&WW articel or a schematic I would very much like to see it.
Perhaps you haven't seen it, but I have two articles on the subject,
"Sensitive Full Range Speakers and Current Source Amplifiers"
and
"Crossovers for Current Source Amplifiers"
(I think these are the titles)
You can download them from www.firstwatt.com
"Sensitive Full Range Speakers and Current Source Amplifiers"
and
"Crossovers for Current Source Amplifiers"
(I think these are the titles)
You can download them from www.firstwatt.com
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