jimjimbo Posted June 30, 2016 Share Posted June 30, 2016 So, who thinks their midrange is too hot? Anyone want to talk about attenuation? Resistors? I was going to ask this at some point, so this is timely..... but does the method of changing the tap on the autoformer, and substituting a 6.8uf cap for the 13uf cap work for a Khorn? Quote Link to comment Share on other sites More sharing options...
Deang Posted June 30, 2016 Author Share Posted June 30, 2016 On 6/30/2016 at 10:56 AM, jimjimbo said: On 6/30/2016 at 10:24 AM, Deang said: So, who thinks their midrange is too hot? Anyone want to talk about attenuation? Resistors? I was going to ask this at some point, so this is timely..... but does the method of changing the tap on the autoformer, and substituting a 6.8uf cap for the 13uf cap work for a Khorn? Sure does. Just move the midrange wire from 4 to 3 and change the cap. Another way: move the wire from 4 to 3, and then put a 15 ohm/20 watt resistor in parallel with the driver. Just slide the leads under the screws for negative and positive. This method allows for retaining the 13uF capacitor. Get adventurous and try it both ways - they sound a little different. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted June 30, 2016 Share Posted June 30, 2016 A thread on a battery biased network is coming too I'm a believer. Quote Link to comment Share on other sites More sharing options...
Pete H Posted June 30, 2016 Share Posted June 30, 2016 Great information Dean! I agree this should be pinned. Basic straight forward information with pics, videos and Q&A Quote Link to comment Share on other sites More sharing options...
JDJohnson Posted June 30, 2016 Share Posted June 30, 2016 Your crossovers are so very well done and beautiful Dean! You're very talented! Quote Link to comment Share on other sites More sharing options...
Deang Posted June 30, 2016 Author Share Posted June 30, 2016 The more mistakes you make early, the better they look later. :-) There is a way to do this with only ONE solder joint. Anyone interested in hearing about that? Quote Link to comment Share on other sites More sharing options...
Pete H Posted June 30, 2016 Share Posted June 30, 2016 Absolutely! Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted June 30, 2016 Share Posted June 30, 2016 Get adventurous and try it both ways - they sound a little different. Would you mind explaining "different'....before I go burn a bunch of gas to find two resistors? Quote Link to comment Share on other sites More sharing options...
Deang Posted June 30, 2016 Author Share Posted June 30, 2016 Without the resistor, it sounds a little more forward and lively - which is okay, because you just knocked 3dB off of it. With the resistor, it sounds more subdued - you need more volume to hit the sweet spot -- which is usually too loud for me. I have no idea if that helps or not. 1 Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted June 30, 2016 Share Posted June 30, 2016 Yes, that helps, thanks. 1 Quote Link to comment Share on other sites More sharing options...
mboxler Posted June 30, 2016 Share Posted June 30, 2016 This has always confused me. It seems that the first 2uf cap to the tweeter is in series with the 13uf to the mid. The result would be a 1.75uf cap as the first part of the third order filter to the tweeter. Changing the 13uf to 6.8uf would equate to a 1.5 cap. Would it have been better to run a separate wire from input + to the 2uf cap? Am I missing something? Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 30, 2016 Share Posted June 30, 2016 The diagram does make it look like it's being connected after the 13uf capacitor. From the layout, it looks like it's an 18db/octave high pass to the tweeter and 6db/octave to the mid and 6db/octave low pass to the woofer. There's no bandpass filter on the mid; just a natural roll off on the high side. Quote Link to comment Share on other sites More sharing options...
muel Posted June 30, 2016 Share Posted June 30, 2016 Without the resistor, it sounds a little more forward and lively - which is okay, because you just knocked 3dB off of it. With the resistor, it sounds more subdued - you need more volume to hit the sweet spot -- which is usually too loud for me. I have no idea if that helps or not. I think you hit the nail on the head with your description of using the resistor. Did you ever hear or try different resistor brands? I only tried Mills so far. This has always confused me. It seems that the first 2uf cap to the tweeter is in series with the 13uf to the mid. The result would be a 1.75uf cap as the first part of the third order filter to the tweeter. Changing the 13uf to 6.8uf would equate to a 1.5 cap. Would it have been better to run a separate wire from input + to the 2uf cap? Am I missing something? It is a matter of how the caps are functioning. Easier way to look at it as that the 13uf cap is filtering the lows up to the midrange and the 2uf is filtering out the lows and mids up to the highs. The 13uf cap lets the mid and high frequencies through and the 2uf lets the high frequencies through. Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 30, 2016 Share Posted June 30, 2016 Let's say the 13uf cap is crossing over at 600Hz and up, it has no bearing on what is going on with the tweeter because the (2) 2uf caps used with the inductor creates a steeper 18db/octave high pass at, let's say, 5khz and up. Basically, the first 2uf cap could be placed on the (+) input position on the terminal strip and it would do the same thing. Dean, am I right in that? Quote Link to comment Share on other sites More sharing options...
Wirrunna Posted July 1, 2016 Share Posted July 1, 2016 This has always confused me. It seems that the first 2uf cap to the tweeter is in series with the 13uf to the mid. The result would be a 1.75uf cap as the first part of the third order filter to the tweeter. Changing the 13uf to 6.8uf would equate to a 1.5 cap. Would it have been better to run a separate wire from input + to the 2uf cap? Am I missing something? The capacitor being in series was discussed in a thread on the super AA - https://community.klipsch.com/index.php?/topic/65508-question-on-super-aa-crossover/ Quote Link to comment Share on other sites More sharing options...
Don Richard Posted July 1, 2016 Share Posted July 1, 2016 Hooking the 2uf in series with the 13uf is a significant improvement, and is often referred to as an "improved three way network". Basically, the order of the tweeter network is increased. This improves tweeter protection. It is also a constant resistance network, which the typical parallel network is not. Quote Link to comment Share on other sites More sharing options...
Deang Posted July 1, 2016 Author Share Posted July 1, 2016 The tweeter sounds too hot when you move it to input positive, the series connection sounds better to me. Quote Link to comment Share on other sites More sharing options...
Wirrunna Posted July 2, 2016 Share Posted July 2, 2016 Dean, a question on layout. I notice that you have used what I would call a daisy-chain earth. Back when I was building amplifiers a central earth point was mandatory otherwise there was hum and extra distortion, especially in class A amps and class AB amps that were operated at quiescent currents above 200ma. On my K-Horns the AK-3 crossover has a central earth plate. After updating the capacitors and adding a terminal block I retained the central earth system which certainly increased the wiring required and doesn't look as nice as a daisy chain earth along the terminal block. Is it because crossovers are essentially passive devices that central earthing is not required? Quote Link to comment Share on other sites More sharing options...
Deang Posted July 2, 2016 Author Share Posted July 2, 2016 Yes, that's right, there is no "earth ground". It's more rightly referred to as "common". Quote Link to comment Share on other sites More sharing options...
Don Richard Posted July 2, 2016 Share Posted July 2, 2016 Also no power supply to cause any hum in a passive crossover. Quote Link to comment Share on other sites More sharing options...
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