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[Edit] The tweeter distortion problem was fixed by moving the RCA inputs to my receiver to the "CD" input, instead of the "Phono" input.
This is my first time with DIY speaker building, and I have quite enjoyed the ride.
After researching and talking about it, I dove in and bought all the parts necessary to build one center channel speaker according to the schematic and BOM posted by Jon Marsh.
So when the parts arrived, I broke out my soldering iron and hot glue gun, and assembled the crossovers. I connected everything up to the drivers outside the speaker box for testing first, connected them to an amp and turned it on at a very low volume to see if something goes boom.
When I turned up the volume to a whisper-level, I was delighted at first that everything worked, well at least at first... I put my ear up to each of the two woofers, the mid, and the tweeter, and sweet music was coming out of each. After about 30 seconds when I was satisfied everything was ok, I tried turning up the volume just a little bit, at about the loudness of somebody talking softly, and then I heard a bit of cracking/buzzing and popping distortion sounds coming from the tweeter only when there was a bass hit. The woofers and mid sounded completely fine. I turned down the volume back to where it was when I started, and the distorted bass from the tweeter continued, although quieter. I start to suspect something is wrong with the tweeter crossover because tweeter should not be asked to create booming bass.
I turned off the music and the amp, unplugged the leads, triple checked all my solder joints, re-tightened all the distribution block connections, and combed through all the circuits to be sure I hadn't mis-wired something. Couldn't find anything wrong. Plugged everything back in and turned the music back on, and the sound was clear again... for about 10 seconds, then the distortion came back from the tweeter. Makes me wonder if something goes wrong once the crossover capacitors have a chance to charge up?
During assembly of the tweeter crossover I did notice two discrepancies.
1. The first is that R14 in the schematic indicates 12 ohm, whereas in the BOM it still says 6 ohm, although this was clarified by ThomasW that R14 is indeed 12 ohms.
2. The second is that L6 in the schematic says 1.2 mH whereas in the BOM , L6 is a 1.5 mH Jantzen coil PE part #255-426.
Images not available
I bought what it says in the BOM, given that I see what looks like a 1.5 sticker on L6 of Jon's crossover.
In addition the diagram below also shows 1.5mH.
Image not available
"NOTE the value for the C6 cap in the schematic above should be 6.8mfd, not 6.0mfd. This correction is noted in the C6 value posted in the block diagram and BOM of post #7"
Since I am having a problem I even wonder if the capacitors used in this crossover only work properly in a certain direction? i.e. have I wired one or more caps backwards? I tried to build it in the same way as Jon did, except I put two caps (20 uF + 15 uF) in parallel instead of a 35 uF cap. I also used a single 2 ohm resistor for R12 instead of 2 x 1 ohm resistors...
Could somebody please look at my tweeter crossover and let me know if it looks fine or if I have done something dumb?
Images not available
More photos of the tweeter crossover from various angles (warning: 5MB each)
Images not available
Any advice what to try next to figure out what is wrong would be greatly appreciated!
[Edit] The tweeter distortion problem was fixed by moving the RCA inputs to my receiver to the "CD" input, instead of the "Phono" input.
This is my first time with DIY speaker building, and I have quite enjoyed the ride.
After researching and talking about it, I dove in and bought all the parts necessary to build one center channel speaker according to the schematic and BOM posted by Jon Marsh.
So when the parts arrived, I broke out my soldering iron and hot glue gun, and assembled the crossovers. I connected everything up to the drivers outside the speaker box for testing first, connected them to an amp and turned it on at a very low volume to see if something goes boom.
When I turned up the volume to a whisper-level, I was delighted at first that everything worked, well at least at first... I put my ear up to each of the two woofers, the mid, and the tweeter, and sweet music was coming out of each. After about 30 seconds when I was satisfied everything was ok, I tried turning up the volume just a little bit, at about the loudness of somebody talking softly, and then I heard a bit of cracking/buzzing and popping distortion sounds coming from the tweeter only when there was a bass hit. The woofers and mid sounded completely fine. I turned down the volume back to where it was when I started, and the distorted bass from the tweeter continued, although quieter. I start to suspect something is wrong with the tweeter crossover because tweeter should not be asked to create booming bass.
I turned off the music and the amp, unplugged the leads, triple checked all my solder joints, re-tightened all the distribution block connections, and combed through all the circuits to be sure I hadn't mis-wired something. Couldn't find anything wrong. Plugged everything back in and turned the music back on, and the sound was clear again... for about 10 seconds, then the distortion came back from the tweeter. Makes me wonder if something goes wrong once the crossover capacitors have a chance to charge up?
During assembly of the tweeter crossover I did notice two discrepancies.
1. The first is that R14 in the schematic indicates 12 ohm, whereas in the BOM it still says 6 ohm, although this was clarified by ThomasW that R14 is indeed 12 ohms.
2. The second is that L6 in the schematic says 1.2 mH whereas in the BOM , L6 is a 1.5 mH Jantzen coil PE part #255-426.
Images not available
I bought what it says in the BOM, given that I see what looks like a 1.5 sticker on L6 of Jon's crossover.
In addition the diagram below also shows 1.5mH.
Image not available
"NOTE the value for the C6 cap in the schematic above should be 6.8mfd, not 6.0mfd. This correction is noted in the C6 value posted in the block diagram and BOM of post #7"
Since I am having a problem I even wonder if the capacitors used in this crossover only work properly in a certain direction? i.e. have I wired one or more caps backwards? I tried to build it in the same way as Jon did, except I put two caps (20 uF + 15 uF) in parallel instead of a 35 uF cap. I also used a single 2 ohm resistor for R12 instead of 2 x 1 ohm resistors...
Could somebody please look at my tweeter crossover and let me know if it looks fine or if I have done something dumb?
Images not available
More photos of the tweeter crossover from various angles (warning: 5MB each)
Images not available
Any advice what to try next to figure out what is wrong would be greatly appreciated!
[Edit] The tweeter distortion problem was fixed by moving the RCA inputs to my receiver to the "CD" input, instead of the "Phono" input.
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