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mboxler

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Everything posted by mboxler

  1. Interesting! I guess I was misremembering. Thanks, Mike
  2. Thanks for the clarification. I always thought that the K-77M could run lower with a steeper filter (voltage wise), but it's SPL was too low below 6000hz to sound right. Or I could be misremembering 🙄
  3. I use REW. I don't have an AL-X crossover, but the high pass of the ALK ES5800 is almost identical. Here is a plot of the voltage across a real K-77M. Still can't figure out why REW gets cranky at the lower SPL.
  4. I believe the AL-4 is 4500hz, due to the K-77F(?).
  5. Pretty sure the high pass filter to the K-77 was identical on the AL, AL-2, and AL-3 crossovers...around 6000Hz. Mike
  6. Here are my LTspice and REW plots for the high pass of the ALK ES5800t crossover. Can someone tell me what's going on with REW below the 70db level? Is there a measure setting I'm getting wrong, or is this noise on the TRS connection from the crossover to the Line In jack? Thanks, Mike
  7. Please don't get me wrong. If you are satisfied with your results then that's all that matters. I assume you meant 44.8 total inductance (2.8 * 16) 🙂. Your tests appear to confirm my math. For example, tap 4 represents 75% of the total windings, therefore the output voltage will be 75% of the input voltage, or -2.5db. I hope I read your plot correctly. Likewise, tap 2 represents 37.5% of the total windings, resulting in a -8.52db drop in voltage. I guess I'm too much of a perfectionist, and was trying to get your model closer to -3db and -9db. I was also reminding all that on the T2A, tap 3 is actually -3.35db. I often wonder, regarding a new Crites Type AA crossover, that the combination of the 3636 autoformer on the -3db tap and the lower ESR Sonicaps might be the reason it seems brighter than a T2A/polyester cap combination. Mike
  8. Sorry I'm not much help. If I understand you correctly, you are saying 1/16 of the total autoformer inductance equates to 3db (?). I'm saying that it's purely the ratio of input turns to output turns that dictates voltage change. In your example (4 2.8mh inductors connected in series and mutually coupled), each inductor would have the same number of turns. Therefore, if you connect the input to the top of the first and the bottom of the fourth, and connect the output between the first/second inductor and the bottom of the fourth inductor, your total output turns will be 75% of the input turns. As a result, your output voltage will also be 75% of your input voltage, or -2.5db. The next tap, 50%, or -6db, and the last tap, 25%, or -12db. If, in your model, you replace the 13uf capacitor with a wire, you should get the same input to output voltage changes as I just described (I think). Mike
  9. I've been told that my T2A model isn't exactly accurate when it comes to phase, so I'm not sure. I don't think tap 0 greatly affects the tweeter circuit (it's more the series 13uf/2uf). That said, it looks like the tweeter circuit greatly affects the squawker circuit. Again this is my Type AA, T2A model, with the squawker (14.2 ohm resistor) on tap 4 (-3.35db). The red trace is the tweeter circuit disconnected. Mike
  10. My fault. I noticed differences in the plots and was curious why. Although the major difference had to do with the load resistor (I use 8 ohm), I couldn't help but notice the autoformer model difference as well. Apologies to the OP. Mike
  11. Agree! Taps 0 - 3 equals one half, or 5/10 of the total turns. So...(5*5)/(10*10) = 25/100 = .25 44mh * .25 = 11mh. I can do the same everywhere. Taps 5 - 4 equal 3.2/10 of the total turns. (3.2*3.2)/(10*10) = 10.24/100 = .1024 44mh * .1024 equals 4.5056mh Taps 4 - 0 equal 6.8/10 of the total turns. (6.8*6.8)/(10*10) = 46.24/100 = .4624 44mh * .4624 equals 20.3456mh If you really want easy -3db, use 2.93/10 for taps 5 - 4 and 7.07/10 for 4 - 0. We're probably stating the same thing in different ways (Isn't math great)! Mike
  12. Sorry if I'm not following your math. Let's say the inductance between tap 0 and tap 5 is 43mh. Also, keep in mind that tap 4 on the T2A is actually -3.35db, 10 volts in = 6.8 volts out. Taps ratio of total turns Ratio of total inductance 5-4 .32 .1024 or 4.4032mh 4-3 .18 .0324 or 1.3932mh 3-2 .144 .020736 or 0.891648mh 2-1 .106 .011236 or 0.483148mh 1-0 .25 .0625 or 2.6875mh Not sure if this gets us on the same page, but I tried. Mike
  13. Okay, I saw this earlier but never commented... The simulation of the autoformer isn't quite right. There are a few good models, this is the one I came up with. The autoformer is one big tapped inductor, not several inductors in series. You will notice the K directive. It tells LTspice to mutually couple all the series inductors. The total inductance of my model is around 44mh, tap 0 to tap 5.
  14. Would you please post one of the LTspice models? Also, I'm not a bat 🦇. Could you end your simulation at 20000 hz? My simulation is quite a bit different. Thanks, Mike
  15. Finally got REW to work, I think. Discovered I can use my computers Line In to capture the voltage across the crossover outputs. Line Out-->Amplifier with Volume control-->Crossover Input-->Crossover Output (with dummy resistor across the output as well)-->Line In. I had success with a simple 47uf capacitor/8 ohm resistor circuit combined with a 2.5mh inductor/6 ohm resistor circuit...Pretty close! Unfortunately, my test "jig" broke (two wires soldered to a pcb mount 1/8" jack's pins). Ordered a breakout board that I hope works better. I had to be careful and use an amplifier with single ended outputs. I assume connecting an amp with bridged outputs to the Line In jack would be a disaster. I also don't know what the input impedance of my computer's line in jack is. I assume it's impedance, in parallel with the test resistor, might affect the REW test. Curious how others test crossovers before installing them in their speakers. Mike
  16. If using active filter for high pass... It would be best to bypass the 13uf capacitor. Disconnect the 13uf capacitor from the crossover input, and run a wire from that same spot to tap 5 of the autoformer. If you are not comfortable with soldering you could use an alligator clip to connect to that tap for testing. Unfortunately, the 4uf capacitor is in series with the 13uf capacitor, effectively creating a 3uf capacitor to the tweeter. Once you bypass the 13uf capacitor, the 4uf capacitor is on it's own. The voltage across the tweeter will increase sooner than it would with the 13uf connected.
  17. Will your active crossover be sending the low-pass signal to the woofer amp and the high-pass signal to the A/4500 amp? Or will you be sending the full signal to the A/4500 amp? Mike
  18. Just to be clear... Run a wire from the terminal cup input straight to the K-33, removing the connection to the inductor. Run cables from your amp to the new AK-3 sitting in the top hat. Run cables from woofer out to the bottom terminal cup terminals. Run cables from squawker out and tweeter out to the K-55 and K-77 (terminal cup not used). The upper terminals on the terminal cup will be unconnected (looking from the outside). Clever, as long as you know that the low pass fuse is now between the crossover and the K-33 and the high pass fuse is now unused. That should be okay. Mike
  19. Here's what I made... Another option is to replace each 70uf capacitor with a 50uf and be done with the woofer section. The inductor should be fine. Then run a cable from the HF output of the terminal cup to the HF input of the crossover. Mike
  20. Are you wanting to stream wirelessly from your wife's laptop to a device connected to your Sony receiver? Does your receiver accept S/PDIF or do you want to connect via RCA? Do you want to control your playback from a tablet/phone? Do you also want the ability to stream music over the internet...Spotify, Tidal, Pandora, etc? My favorite device is the Squeezebox Touch (no longer made but still very popular). You would need to run a server program on your wife's laptop however. I have built Squeezebox devices using ESP32 as well. DIY, but a blast to play with! Mike
  21. I do have a folder containing all the AP-XXX schematics that I downloaded from Al's website a long time ago. It contains his AP-700 schematic. Let me know if you want me to PM you that folder. Mike
  22. Do you have the schematic for the ES400? If not, there's one on Al's website, in the Extreme Slope section. I assume it's the latest schematic. I believe you can take those values and divide all of them by 1.75 (700/400) to get an ES700. I think the first series inductor is 3mH (?). Do you already have the ES5800, or were you planning on a 2-way system? If you would like, I can try to run some before/after simulations just to see how the old/new values play together. I can't guarantee the resulting values will equal Al's ES700 though. Maybe wait until someone posts an official schematic before trying this approach. Mike
  23. Which autoformer taps are you currently using? If I remember correctly, I was using -12db at the least to tame those high sensitivity drivers. Mike
  24. This may help with I2S https://hackaday.com/2019/04/18/all-you-need-to-know-about-i2s/ Yes, the amp has a built in DAC, otherwise it's pretty much identical to the MA12070. In fact, all of the analog input pins on the MA12070 are digital input pins on the MA12070p. Since I can't get analog out of the ESP32 (I2S or SPDIF only), the MA12070p is a great fit. Here's the MA12070p datasheet. Infineon-MA12070P-DS-v01_00-EN.pdf Mike
  25. This took a lot longer to get going than it should have 🙁 This is an ESP32-WROVER (running Squeezelite-ESP32) connected to a Merus MA12070p (Class D) reference board (on the left). The MA12070p chip is I2S input only, hence the wires for bit clock, word clock, and data. Other wires are for I2C connection. I'm a Squeezebox fan, and with this setup I can stream Tidal, Spotify, Radio Paradise, etc. Playing through a pair of full range speakers now but really sounds nice! Mike
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