BuzzzFuzzz Posted November 9, 2022 Posted November 9, 2022 (edited) G'day Folks. Here's the link for the restoration thread... I wanted to start a specific thread for the crossovers, hoping for some advice, please? I have two pair of Celef, Mini Pro Monitors... the older ones in the above thread, and also a pair of newer ones with different tweeters and woofers, belonging to @TheBlackDisc, who actually gave me the first pair. @VinylChef has done the surrounds on my woofers, and also repaired the tweeters from the newer pair. They are back and ready to assemble. David has done some other work for me, he's very knowledgeable and helpful, and does great work... Thanks mate. The cabinets are almost done, and now it's time to tackle the crossovers. The older pair from my monitors... The newer pair... Here we go... The plan is to replace all caps with the same, or close values, as a couple of Jantzen caps I've looked at don't come in the exact value, just a few points off. We would like to hit the brains trust for options here. What brands to consider for Celef monitors? How much should we aim to spend for the quality of the speakers? Should I source caps with the exact value of the originals? I believe inductors are not essential to replace in older crossovers, but I'm curious if I should replace the iron cores with air cores? Is the thickest guage inductor the best option? With the older crossovers there are ceramic resistors. Should these be replaced with ceramic, or another type of resistor? The newer crossovers have a black, square cap. Why are different caps used? Should I replace them with cylindrical caps? As a side project, I'm working on a pair of Richter Dragons MkI, and doing these crossovers at the same time... Not the prettiest crossovers I've seen. The wires for the inductors are twisted together. I've not seen that before, is this usual? The winding of the wire looks a bit messy too. Does this affect performance? Any and all advice welcomed and appreciated. Cheers. Ant. Edited November 9, 2022 by BuzzzFuzzz
muon* Posted November 9, 2022 Posted November 9, 2022 (edited) Go for as close as you can with cap replacements, but don't go nuts trying to get exact if you can only get close.. Good to get rid of those old Elcaps (electrolytic caps that can eventually explode), they are usually by now between 50% or much more in capacitance over the rated from my experience.. Edited November 9, 2022 by muon* 1
RoHo Posted November 9, 2022 Posted November 9, 2022 Crossover parts selection is the “wheel of compromise”. Air core inductors are technically superior to iron core but are bigger and more expensive. Film caps likewise to electros. So the designer compromises by putting maybe one film cap where it matters most, series to the tweeter, and maybe using some air core inductors where the values are small. Specifically to your case, there are numerous boutique caps available but Jantzen are good because Nigel at Speakerbug is local and offers superb service in my experience. In the world of XO caps +/-5% is irrelevant and even +/- 10% is no big deal. To keep things at the original values you can parallel two smaller caps. Aircore inductors are significantly bigger which means significant changes to the construction. You also have to take into account the change in resistance of aircore vs iron. I wouldn’t bother. The wire gauge is determined by the amount of power/current you are going to throw at the speaker. A large gauge, high value air core inductor is massive in weight, size and cost and that’s why the series woofer inductor is often iron core. Compromises, compromises! 1 1
andyr Posted November 9, 2022 Posted November 9, 2022 1 hour ago, RoHo said: Crossover parts selection is the “wheel of compromise”. Agreed! So it's all down to: how much you are willing to spend, and whether you have space inside the cabinet to take the new, bigger components. 1 hour ago, RoHo said: Air core inductors are technically superior to iron core but are bigger and more expensive. Film caps likewise to electros. So the designer compromises by putting maybe one film cap where it matters most, series to the tweeter, and maybe using some air core inductors where the values are small. Yes, the spkr designer does that ... but you - as a tweaker/DIYer - don't have to. 1
RoHo Posted November 9, 2022 Posted November 9, 2022 11 hours ago, andyr said: Agreed! So it's all down to: how much you are willing to spend, and whether you have space inside the cabinet to take the new, bigger components. Yes, the spkr designer does that ... but you - as a tweaker/DIYer - don't have to. Indeed you have a lot more freedom than the designer of a commercial product. But unless you take cost totally out of the equation, which admittedly some DIYers do, you still have to draw the line somewhere. It would be quite easy for the OP to build replacement crossovers that cost 10 times what the speakers are worth and is as big as the speaker itself. I'm sure he won't but he has to decide where to draw the line and then what the best allocation of the budget is. 1
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