Guest Bret Posted February 25, 2005 Report Share Posted February 25, 2005 >Measuring the transfer function from the input terminals to each of the drivers loaded in the system would be the way to figure out the difference between the two crossovers<I'm seriously ignorant. What would this tell me? The crossovers appear identical; but his transformer has a hand-written "sampled" sticker on the top and mine doesn't look anything like his.Anyone know who "ML" might have been? Evidently he assembled at least the switch board.Bret Link to comment Share on other sites More sharing options...
Guest Bret Posted February 26, 2005 Report Share Posted February 26, 2005 >2. Digikey.com has a huge selection of Panasonic caps; of these, the SU series bipolar caps seem to be very good, at almost no cost difference to the caps from Partsexpress.I am still gathering info and have not decided which ones to try. <I looked at those. They've got +/- 20% tolerances. . . I'm not that tolerant, myself. That means between any two you could have a 50% difference. I'm betting I could hear that.Bret Link to comment Share on other sites More sharing options...
Pete B Posted February 26, 2005 Report Share Posted February 26, 2005 If you hear a difference and you've ruled out the drivers, then it must be the crossover. Measuring the two crossovers will determine where the differences are. Once you find which section(s) is different then we would want to determine which component(s) are causing the difference. I can usually determine the cause if I have measured responses for both the "target" and modified crossover through simulation. I would also need the in system input impedance of the drivers which is also easy to measure.I don't think I saw a schematic for the 10pi crossover did I miss it?Pete B.>>Measuring the transfer function from the input terminals to>each of the drivers loaded in the system would be the way to>figure out the difference between the two crossovers<>>I'm seriously ignorant. What would this tell me? >>The crossovers appear identical; but his transformer has a>hand-written "sampled" sticker on the top and mine doesn't>look anything like his.>>Anyone know who "ML" might have been? Evidently he assembled>at least the switch board.>>Bret Link to comment Share on other sites More sharing options...
Pete B Posted February 26, 2005 Report Share Posted February 26, 2005 I see people looking for good quality NPEs and I'd guess that most know about these from Madisound (scroll down to the bipolar section): http://madisound.com/benniccaps.htmlThey're good quality 10% caps, I've used them when I need large values and they work well. They have typical electrolytic characteristics.Just wondering if anyone has measured the value of the unlabeled inductor in the AR-9 crossover schematic. Inductance and DC resistance would be helpful.It looks like the 10 mH inductors in the AR-9 are stacked and therefore coupled, is this true?Pete B.>So the tinkering continues. I'm going to do something about>the 2500uF caps and the resistors in mine and see if something>else will change.>>From what I'm hearing so far, my AR-9s are going to get NPEs. >I'm not convinced that more expensive is better in this case. >We'll know soon enough.>>Bret Link to comment Share on other sites More sharing options...
Pete B Posted February 26, 2005 Report Share Posted February 26, 2005 Correction:The other crossover schematic that I first checked was difficult to read, I have another one here that shows the 50uF as 350uF which I think is the correct value. My comments still apply.Pete B.>You talk about a zobel, does your crossover match the one here>with 3.83 mH in series with the woofers then 50uF - 1 ohm in>series as a shunt across the woofers? Have you traced out>your crossover? I'm willing to help if your interested.>>Pete B. Link to comment Share on other sites More sharing options...
Guest Bret Posted February 26, 2005 Report Share Posted February 26, 2005 >I don't think I saw a schematic for the 10pi crossover did I miss it?<If there is one available, I haven't found it either. Which isn't making life any easier. I saw a multimeter, I think at Digikey, that will do mH as well as a lot of other stuff. I was thinking about getting it just so I could provide a 10pi schematic. Also, on the 9, there was talk at one time about the schematic we have not-being correct. I've got an hour, let's see what I can do.What would I measure, and how, on this transformer in the 10pi?Bret Link to comment Share on other sites More sharing options...
Guest Bret Posted February 27, 2005 Report Share Posted February 27, 2005 I'm not convinced those are 10mH inductors. I think these labels are AR part numbers, not absolute values for the chokes.Yes, they are stacked and coupled. Also, on the schematic available on the forum there is an inductor which is said to be a 2.63mH. In my speaker, clearly the sticker on that inductor says 13. The inductor with the missing label on the schematic is PN 9.Unless we can find-out what these part numbers correspond to, we still don't know anything, I'm betting.Take a gander at the crossover pictures I just uploaded here:http://photos.yahoo.com/tbret Link to comment Share on other sites More sharing options...
Pete B Posted March 1, 2005 Report Share Posted March 1, 2005 Thanks for the pictures and they remind me that some of the AR speakers use big industrial looking Sprague Compulytic and/or Callins caps. It would be good to get the detailed specs on these caps - they probably have lower than typical ESR. Capacitors that are subjected to high currents at high frequencies heat due to their ESR and age faster when the electrolyte chemical is heated. This is typically an issue in switcher power supplies where temperatures can get very high.It's not usually an issue in speakers but since I mentioned the Bennic NPEs I just wanted to add that a better cap, lower ESR and ESL can be made by paralleling smaller values for larger total values. Smaller caps often have lower ESR and paralleling them divides the value by the number of caps used. I prefer poly caps on the mid and tweeter and I don't go for the high priced units unless someone else is paying for them and wants them. I think the 5% GE (GE41L) poly caps at Madisound are a good value but have not tried them.Caps do "explode" (the rolled up plates come flying out) when exposed to excessive ripple current, it happened in one of my experimental switchers, - only once.Pete B.>I'm not convinced those are 10mH inductors. I think these>labels are AR part numbers, not absolute values for the>chokes.>>Yes, they are stacked and coupled. >>Also, on the schematic available on the forum there is an>inductor which is said to be a 2.63mH. In my speaker, clearly>the sticker on that inductor says 13. The inductor with the>missing label on the schematic is PN 9.>>Unless we can find-out what these part numbers correspond to,>we still don't know anything, I'm betting.>>Take a gander at the crossover pictures I just uploaded here:>>http://photos.yahoo.com/tbret Link to comment Share on other sites More sharing options...
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