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Proprius daisy-chaining for driving RAAL SR1a

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 04 Mar 2020 at 6:42am
Going up from 1 watt in decibel increments:

0 - 1
1 - 1.26
2 - 1.6
3 - 2
4 - 2.5
5 - 3.2
6 - 4
7 - 5
8 - 6.3
9 - 8
10 - 10 (sounds twice as loud as 1W)
11 - 12.6
12 - 16
13 - 20
14 - 25
15 - 32
16 - 40
17 - 50
18 - 63
19 - 80
20 - 100 (sounds twice as loud as 10W)
21 - 126
22 - 160
23 - 200
24 - 250
25 - 320
26 - 400
27 - 500
28 - 630
29 - 800
30 - 1000 (sounds twice as loud as 100W)
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Ash View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 08 Mar 2020 at 11:44pm
I have been speaking with Heinz some more and he explained that the main reason that he did not implement a ribbon driver for K1000 or MySphere is because of the high power requirement needed to obtain a fast and precise impulse response. I assume Mr Slee, master of slew rate, is confident the Proprius can swing the voltage fast enough to get a ribbon driver to start and stop with the speed needed.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 09 Mar 2020 at 9:47am
While others were tied to a kettle element embedded in an aluminium block, containing a coiled stainless steel pipe, which had to be plugged into the mains, just to make damp disco smoke; I was busily writing up the patent application for a control system which instantly went from zero current to 95 amps. It used the stainless steel pipe directly as a heating element; infra-red receivers fed-back instantaneous temperature data to switch the current off, and back on to ensure the element did not melt; and an interlocked a pump fed triethylene glycol through it, such that it produced instantaneous smoke. It ran off a golf cart battery and was handheld and push-button controlled.

Remember induction loops for the hard of hearing? Do they still do them? They are circuits of single core conductors (laid under floors or embedded into walls), which are the equivalent of short circuits, but when fed by a power amp via a suitably rated power resistor, produce magnetic field signals which can be picked up by induction equipped hearing aids; not only within the loop but far beyond it.

Sheltered housing developments might have 50 or so apartments, all equipped with 32-ohm speaker/mics for control centre communication. In the event of a fire or similar threat, communication with all occupants at once became an essential requirement. Not only was it a 0.6-ohm load, but it was very capacitive with all the wiring paralleled together via the switching.

Damping factor is supposed to illustrate the control the amplifier has over the transducer in its ability to brake its movement. Try it. Damping factor is quite imaginary. It can only brake the movement in one direction by applying current flowing in the opposite direction. Therefore it would be better to call it the driving impedance.

The ribbon headphones you have been inquiring about use a series resistance of approx. 5.6 ohms, to drive a 0.2 ohms stainless steel membrane. The amplifier's driving impedance pales into insignificance compared to the 5.6 ohms series resistance, because the driving impedance IS the 5.6 ohms series resistor (or series-parallel combination making up that value). How can it be any other?

As for slew rate; it is important from an "inside the amplifier circuit" point of view, to reduce transient distortion, but I don't think many transducers (if any) would be able to respond and make full use of 90V/uS.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 09 Mar 2020 at 11:30am
Thanks Graham. By the way, the ribbon diaphragm material is aluminium, not stainless steel. I might see if I can borrow the SR1a on loan rather than buy blind. Curious to compare them to MySphere although I know neither will image like my newly-acquired Alpair 11MS speakers.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 09 Mar 2020 at 6:24pm
Originally posted by Ash Ash wrote:

By the way, the ribbon diaphragm material is aluminium, not stainless steel.


...taken Cool
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