Rerurn to Romy the Cat's Site

Well, without any theory or gut feeling to guide us, we are flailing around. So let me tell you what my instincts tell me and you can take it or leave it.

I think the main advantage of the EM is reducing flux modulation. There was a post recently by one of the attendees who went with Feastrex claiming that Dr Kilppel (of famous measurement tools suite) measured one of their drivers and it featured the lowest level of flux modulation he'd seen yet. With that in mind: you can think of the voicecoil and field coil as forming a primary and secondary of a transformer.

To reduce flux modulation to a minimum, I wonder if one would like the secondary (field coil) and power supply to have as low an impedance as possible, ie resembling a shortiing ring.

This point of view might imply that:
1) Lower resistance field coils and supplies might sound better than high impedance (one could actually test this by comparing the RCA 1428 and 1443, which are identical save for FC voltage)

- here's are my new ideas

2) Use a FC supply having a negative impedance to offset as much of the DCR of the coil as possible (til you get stability problems)

3) Presumably we need to maintain good behaviour at HF as well, in which case, do we want to layer the FC windings in order to reduce interwinding capacitance - ie much as if we were designing an anode choke etc. Need to balance this with the reduction in flux available and reduced heatsinking.

You can also take the following with a pinch of salt, but people have reported drivers sounding better with a SlA battery supply rather than a bench one., so much so that they are willing to string 10 or 20 in series to get the required voltages.

Anyway, this is an exciting (pardon the pun) project, look forward to hearing how you get on cos I would love to try this myself.

Rerurn to Romy the Cat's Site