Crossover Problem Solving

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      • March 24, 2025 at 12:39 am #57268

        I’m about to finish my 2nd pair of Toid/Kirby tower speakers and I encountered an issue. I decided to make this set capable of being bi-amped. I have 2 separate crossovers and the connections are bridged at the terminal cup. After getting everything mounted and ready I gave them a test run. Sound came out for about 1 second then a just a thump-thump-thump. I tried both towers with the same result. I unbridged the terminals and it has something to do with the woofer. I tested the woofer alone and it functions as expected. Has anyone encountered this before? Toid advised me to get DATS on the job but I am having some trouble removing the crossover board because I hot glued the heck out of it. I put the crossover on some HDF and glued it to the back of the cabinet.

        If I had to guess, I might have purchased polarized caps (for some unknown reason) and have somehow installed BOTH backwards. I don’t really have any other ideas. Just wondering if anyone else has had this issue before. I’m always finding new mistakes! It’s a gift!

        • March 24, 2025 at 1:00 pm #57280

          Almost sounds like the over-current circuit in the amp is being triggered. That would happen when the output impedance drops too low or is shorted (0 ohms). When you remove the bad load, modern receivers / amplifiers will reset themselves. That’s why when you use just the woofer, it works, as the amp can handle that load.

          Does it happen if you just connect the tweeter?

          If it works then, I would suspect that the crossover is wired in such a way that when the inputs are bridged, they are actually shorted. I can’t imagine how, but it would explain the symptoms.

          • March 25, 2025 at 4:59 pm #57308

            The tweeter alone works fine. Sorry for late response. I just got back from vacation and my job assignment had changed and I’m working 3rd shift now. I’m off today and I’m going to see if I can pop off the low pass crossover without wrecking the cabinet and test it with DATs.

            • March 26, 2025 at 4:11 pm #57315

              Using your DATS, do 3 measurements:

              1. Woofer through its crossover

              2. Tweeter through its crossover

              3. Both together through the bridged connection.

              You should find a clue somewhere in there.

              • March 26, 2025 at 6:58 pm #57317

                I bought a mini crowbar from Lowe’s last night. Hoping I can pop off the CO board with that.

                • March 26, 2025 at 8:38 pm #57323

                  The mini crowbar and hammer worked great. I’ve got the board inside and checked it on DATS. The inductor should be 2 mh. It is 2.051 mh. The 22 mf grounded cap measured 23.48 mf. The bypass cap that is supposed to be .22 mf measured 1801 mf. I think I might’ve found the problem.

                  I called Parts Express and the tech told me that the value of the cap is way off. I should try removing the cap and see if that helps eliminate the problem. I haven’t tried getting to the other CO board yet. It seems odd that both caps could be bad but maybe it was just a bad batch. I’ll let you know more once I test the other one.

                  • This reply was modified 10 months, 2 weeks ago by btrbandit. Reason: I didn't want to make another post to I just edited this one
                  • April 4, 2025 at 6:46 pm #57426

                    I removed the caps from the crossover and they work fine. I’ll replace them eventually when I make my nest PE order. I’m not paying $10 shipping for $3 worth of caps. Thanks for the helpful hints with this.

                    • April 5, 2025 at 8:41 pm #57431

                      They must have been really bad to basically short things to ground. At least you found the issue.

                      Re: PE parts and customer service – they didn’t offer to replace them for free?

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