You've posted under "general", not DIY. As a man who's just bought his own field-coil drivers, are you up for a bit of DIY?

I know zilch about FC drivers, in terms of how they work with their power supplies? Do you have any feel that you can share with the rest of us about what they need? A steady 5A - implying a 1.5Ohm coil, or does their impedance get modulated by the music and cone movement and is different at different frequencies...?

I am ignorant about such matters, not least because I have no electrical training....and am not looking for a DIY solution...rather a commercially available product.Perhaps the variables are too great, in which case I will end up buying the battery power supply from the supplier of the field coils (Voxativ.) What I can say, is that these field coils are incredibly sensitive to the quality of the supply. But surely there are first-rate commercially available supplies, perhaps my problem is that it needs to be unusually 'beefy'.
What does strike me is how much us hifi types obsess about such joys as tweaking Linn Sondeks and yet really basic stuff about electro-magnetic performance is well below the radar. Jonathon at Music First can produce transformers which appear identicial and yet sound quite different. I suppose these are all examples of how everything signifies.

Slightly off-topic, but I run the stators of my 'Logans, and my source components, from a sequential combination of Isol8 mains RF filter followed by PS Power Plant Premier to regenerate clean mains. Not suggesting that you buy on spec, but if you can borrow similar and try it with the mains linear supply, it might get you somewhere near where you want to go...

Presume you're not putting 12V/5A standing current into each speaker. When I was at school, that was 60W, which is going to make for a hot little driver...?

Cheers
Pete

I have taken the advice of 'Shuggie' and had a chat with Paul Hynes. He is going to make me a couple of monobloc power supplies which should fit the bill. Thanks for the advice.

Have a look here, nothing too much and no field coils

http://www.hificritic.co...t.aspx?g=posts&t=528

I am experimenting, and car batteries are cheap and easy to buy. It is indeed a bit over the top, but then Voigt horns are a bit over the top too. That's why I have a separate room for such silliness. To my ears it is sounding quite wonderful and I am beginning to ask myself if it would be possible to establish a system driven only by batteries. Others seem to have managed it and escaping from the mains becomes more and more tempting as electrical pollution increases.It has dragged sound down quite a lot.And despite valient efforts, I am not sure that anyone has found a truly effective solution, other than escaping from the mains altogether.

Yes, thanks for that. The garage warned me not to discharge car batteries, precisely for the reason you suggest. I do 'trickle charge' them. What I will do in the longer term I don't really know. I am just trying to establish a 'base' set of conditions in my own mind....if I can then find a mains powered supply which sounds as good as the batteries..problem solved! (what are the chances of that?).
Still, you have to experiment a bit to find out . I have always found that the only way with this hobby; advice is most useful, but in the end you have to find out what really works for you.

You can also get sealed lead-acid "high-cyclic" batteries, intended for things like electric wheelchairs. Sonnenschein (yes, these German batteries do have a rising sun as a symbol!) and Yuasa do versions up to around 70Ah. Usually quote something like 600 cycles life when discharged to 40% (i.e. you can draw 60% of its design capacity) each time.

Edited by user 15 October 2011 22:35:23(UTC)  | Reason: Not specified

Vol5 no 4 has coverage of field coil drivers

an interview with Voxative and a review of the Supravox.

the latter nearly did not happen as the reviewer suffered an unfortunate blow up of both review samples due to an amplifier fault , which may have been due to coupling via the field coil and its supply, something we will look into

Martin C

Some more on this ..

a single 12v regulated supply was used ie shared by the two field coils

I do not have a good handle on the equivalent circuit but I presume there may be some mutual inductance coupling and some capacitance coupled across the live amplifier channels and this may have resulted in instability leading to blowing up the voice coils.

Can't be a good idea anyway if you think about it, separate batteries avoid this potential for mutual coupling and could well sound better, partly for this reason.

I would welcome some input on this topic , or related experiences

Martin C

Edited by user 21 December 2011 15:41:25(UTC)  | Reason: Not specified