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| Thread ID: 36024 | 2003-07-29 01:51:00 | Low Pass Filter | Ron Bakker (356) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 163587 | 2003-08-02 02:48:00 | Hi Ron, I've been browsing through the Jaycar Electronics catalogue, and if you are prepared to go to 100Hz crossover frequency, then you can save yourself a lot of trouble as they sell crossover inductors and non-polarized crossover capacitors, also crossover circuit boards :) For 100Hz you need 9mH inductor and 280uF capacitor. Jaycars largest inductance is 9mH at $18.50 catalogue number I.F 1336, and they have a non-polarized capacitor 300uF at $16.75, catalogue number RY 6932. Jaycar are pretty good, I recently ordered a digital panel meter from them by phone at about 3pm, it arrived 7.30am the next morning, from ASuckland to Upper Hutt. |
Terry Porritt (14) | ||
| 163588 | 2003-08-02 02:50:00 | That was a typo in 'Auckland', no disrespect to the Jaffas intended :) | Terry Porritt (14) | ||
| 163589 | 2003-08-02 03:19:00 | Hey I've got this big transformer in the shed with the nearist I can figure is 1mill thick windings on it. Do you think I could use this wire for the inductor. I actually wanted to go lower than 80hz just to keep all vocals away from the Sub. I've just been looking a Jaycar's site, quite interesting |
Ron Bakker (356) | ||
| 163590 | 2003-08-02 03:43:00 | That sounds pretty good Ron, thats about 18 or 19 gauge, amply thick enough. A question of getting the laminations apart, once the first one or two are prised out, the others will come loose. You could make up a wooden center to the transformer coil and put a spindle through, so that it turns easily. With luck the secondary will be an outer winding. Then you could make a simple coil winder with the inductor reel/bobbin mounted in a hand drill. As a matter of interest Ive been measuring numerous secondary windings on transformers, several around 5mH, some at 20mH, and others about 50mh or more, all with heavy gauge wire up to about 16 gauge. |
Terry Porritt (14) | ||
| 163591 | 2003-08-02 03:58:00 | Forgot to say, you wont know how much wire is on there until it is pulled apart. It's rather a lot that you need. A coil with laminations would need very much less, and at the low crossover frequency the losses with ordinary 'mains' laminations would be also quite low. But an inductance meter is needed to do it that way. The other way is 2 Jaycar 5.6mH coils in series, that would be about the same as buying 3x 100gm reels of 22 gauge enamelled wire, and to boot those Jaycar coils are 1mm wire diameter with a resistance of 0.5 ohm, as against about 4ohms using 22 gauge. |
Terry Porritt (14) | ||
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