jwgorman Posted May 14, 2019 Share Posted May 14, 2019 Klipsch historically designed crossovers with a cap feeding an autoformer and then a coil parallel to the driver (like the mid on the Cornwall II for example) Are those true second order crossovers? Quote Link to comment Share on other sites More sharing options...
Deang Posted May 14, 2019 Share Posted May 14, 2019 Yes. 1 Quote Link to comment Share on other sites More sharing options...
jwgorman Posted May 14, 2019 Author Share Posted May 14, 2019 27 minutes ago, Pennywise said: Yes. Thanks Quote Link to comment Share on other sites More sharing options...
JohnA Posted May 14, 2019 Share Posted May 14, 2019 Yes. Putting a component on one side or the other can change the size and probably the cost of that component due to the impedance it operates in to. Quote Link to comment Share on other sites More sharing options...
jwgorman Posted May 14, 2019 Author Share Posted May 14, 2019 2 hours ago, JohnA said: Yes. Putting a component on one side or the other can change the size and probably the cost of that component due to the impedance it operates in to. Thanks John. I understand why Klipsch put caps on the upstream side of the autoformer! Quote Link to comment Share on other sites More sharing options...
windashine Posted May 14, 2019 Share Posted May 14, 2019 … o O (how can you change the cost of a component, if you already bought it ???) Quote Link to comment Share on other sites More sharing options...
JohnA Posted May 17, 2019 Share Posted May 17, 2019 By not buying a bigger one that costs more. Quote Link to comment Share on other sites More sharing options...
pzannucci Posted May 20, 2019 Share Posted May 20, 2019 Caps are expensive. As impedance goes up (from the autoformer) cap size goes down. Good idea. Quote Link to comment Share on other sites More sharing options...
glens Posted May 20, 2019 Share Posted May 20, 2019 I'm gonna nay-say here. I don't see much change in cap value being required either side of the transformer. The impedance is the same enough either side, or at least should be. If anything, it might could cut down on the size of the parallel inductor required if you count the inductance of the transformer, but I believe a coil doesn't act like much of an inductor (the way the inductor proper is being used here) when it's being used as a transformer... Quote Link to comment Share on other sites More sharing options...
mboxler Posted May 20, 2019 Share Posted May 20, 2019 The turns ratio squared of the 3507 is around 6.4, so the series load on the 3uf cap will always be 6.4 times the impedance of the driver in parallel with the inductor. If the cap were on the other side, it would need to be 6.4 times larger to get the same results. Quote Link to comment Share on other sites More sharing options...
JohnA Posted May 21, 2019 Share Posted May 21, 2019 On 5/20/2019 at 7:38 AM, glens said: I'......... The impedance is the same enough either side, or at least should be. If .. No, not accurate. In a TypeA/AA, the impedance is twice as high before the autoformer as the driver, resulting in a cap that is half as large. Quote Link to comment Share on other sites More sharing options...
glens Posted May 21, 2019 Share Posted May 21, 2019 I was unaware that impedance factored through a transformer. I wonder why they were used with amps having output transformers? I always figured output transformers were just for voltage-matching. Got a link to any of PWK's notes on the subject? Quote Link to comment Share on other sites More sharing options...
mboxler Posted May 21, 2019 Share Posted May 21, 2019 As with all transformers, watts in equals watts out, so let's use Ohm's Law. As an example, let's use a T2A autoformer, and apply 2.83 volts to taps 0-5. Taps 0-4 will connect to a 14 ohm K-55 driver at 2.00 volts (-3db). 2 volts into a 14 ohm load equals .2857 watts (watts = volts squared/resistance, or 4/14). Since there's .2857 watts output, there's got to be .2857 watts input. 2.83 volts at .2857 watts equals 28 ohms (ohms = volts squared / watts, or 8 / .2857). As you can see, taps 0-5 appear to be a 28 ohms load. Hope that helps! Quote Link to comment Share on other sites More sharing options...
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