This loudspeaker was made a long time before that. That's why they need custom-built equipment and a lot of protection circuits to make sure it cannot be damaged.
Very nearly - it's a WE 555 driver but with a different horn.
I did some H-bridge motor drivers that had negative output resistance, to compensate for motor resistance and stuffen up the torque/speed curve. I could take out about half the load droop before the whole thing went unstable.
WHAAAT? You are worried about damaging the historic speaker, and you are going to be running the speaker wires in the same conduit as 220 V AC wires? That would be illegal in the US on safety concerns, at the least.
Jon
--- "Negligible", actually, but no.
Wire spacing and the dielectric constant of the jacket makes capacitance, while wire diameter and length makes inductance.
-- JF
Am 28.01.2013 11:38, schrieb Adrian Tuddenham:
Actively damping the bass chassis by removing all R can produce a ridiculously low corner frequency for small speakers, at the cost of efficiency and SPL.
I once have calculated a little bit around such a construction but gave up when I noticed that the system is not even time-invariant. I.e. after a drum kick the voice coil is really hot and its resistance is _much_ higher than b4. A moving target if you want to zero it out, and the combination of small chassis and low efficiency calls for lots of power.
IIRC, one Mr. Stal brought the idea up. With a small circle above the a in Stal.
regards, Gerhard
My 1950 Nash had a speaker with a field coil... it doubled as the power supply (vibrator pak) filter ;-) ...Jim Thompson
Am 28.01.2013 19:43, schrieb Adrian Tuddenham:
Is that any different from a Kelvin connection?
Gerhard
A lot. Someone is not stopping and doing a proper analysis... or situation assessment. ...Jim Thompson
Now who's being obvious?
But wire diameter matters too.
I meant that cable capacitance will probably be negligable for his application. But the cable inductance might be enough to affect the high end.
But spacing matters too. That's the big adjustable in a twisted-pair. If his stuff is like Romex, the black-white spacing is large compared to a tight twisted pair. It's worth thinking about. If it's 3-wire Romex, use the black and white in parallel against the ground wire.
It is legal in the UK as long as the low voltage circuit is insulated to the same standard as the high voltage one.
I hope I shan't have to do it that way, but I must allow for the possibility. The biggest danger would be an electrician muddling up the power and signal circuits, but I shall be terminating the signal circuits well away from any mains equipment, so only the central parts of the run might be sharing a trunking with the mains.
...but bear in mind that this is the first draft. It is bound to contain mistakes and quite a few of the component values are still unspecified.
The link for inserting an equaliser is between Rb and the 2k2 LIN gain control, there will also be power connections for any op-amps which may be necessary. The signal level at that point is nominally 0dBu.
I must have missed his statement about "ancient loudspeaker." But why are you going into flame mode? I asked a reasonable question.
I have no idea what you are talking about. Probably you don't, either. You whine first and think later... if ever.
If you are running 3-wire T&E, you can do remote sense, analogous to a
3-wire RTD. Signal, return, sense. The sense wire gives you half of the total wire drop, so gain up by 2 and add that to the outgoing high side signal.The return wire *is* the sense shunt.
Am 29.01.2013 00:02, schrieb Jim Thompson:
No. It's just a Kelvin connection. Taking the feedback for the PA from there where it counts. Just like a lab power supply with sense contacts. I think there are bipolar power supplies (Kepco?) that could do that.
Gerhard
Sorry. I certainly know what a Kelvin connection is. I meant the OP is not thinking his problem thru clearly. ...Jim Thompson
Still meaningless outside of the UK.
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