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About mboxler

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  1. Class D

    Are there vias on the board to implement this mod for SE inputs? http://www.ti.com/lit/an/slaa719/slaa719.pdf Mike
  2. Help Interpreting impedance plots

    Maybe this old thread from ALK will help??? https://community.klipsch.com/index.php?/topic/106102-developing-a-network-for-the-forte/&tab=comments#comment-1168913
  3. Capacitance Filter Question

    Sorry if you already understand this, but just in case... The Antek transformers are designed for 115 /230 volts. If your voltage is higher, the output will be higher as well. Last summer, our voltage spiked to 133 volts for quite a while until the power company finally fixed it. Is Sure power supply you referenced designed for + / - DC outputs?. If you used the same an4434 transformer wdecho used and wired it for 115v (inputs parallel, outputs series), you'll get both a + 48 volt dc output and a - 48 volt output. You would only use 1 of the outputs. I guess if you wired the inputs in series (which I assume wdecho did???), then you would get +24 and - 24. You would then hook up your amp ground to -24 and positive to +24, which is the same as 0 and +48. I hope I got that right. Mike
  4. Autotransformer ID

    This chart comes from Bob Crites web site... http://www.critesspeakers.com/3636atz.pdf As you can see, if you measure the inductance between taps 0-5, divide it by 2.833 (9db), you should get the inductance between taps 0-2. If you have a good DCR meter, I believe you can accomplish the same thing. I measured the DCR on a 3619 autoformer. .37 ohms between taps 0-5. .14 ohms between taps 0-2. .37 / .14 = .2.64. My meter only carries out to 2 decimal places, so this falls between 8 and 9 db attenuation. Would you agree djk? Mike
  5. Autotransformer ID

    My guess...a T10A autoformer, which will reduce the voltage by 9dB. You would need to pass a low voltage sign wave across 0 and 5 and measure it. The voltage across 2 and 5 should be equal to .3535 times the input voltage. You would need a true RMS meter to measure the voltage. Mike
  6. AL crossovers

    Would it not be more flexible to place a 26uf cap after the autoformer? Seems that you could change the output taps to whatever value you want without the need to change the cap. Mike
  7. Like new Reckhorn DSP-6 digital crossover, purchased new 2 years ago. Could never get a manual, but I was able to figure out the basic way to configure. I'll be happy to preload the unit with a specific configuration if requested (slopes, crossover points, delays, gain). According to the webpage... "The program is running on all operating programs Window XP to Windows 8 up to 32-bit, but not on 64-bit versions and Apple." I installed it on Windows 7, and it still running on 64 bit Windows 10. Original box. Will include a better USB cable than the one shipped with the unit, as I was having trouble connecting with the stock cable. https://www.reckhorn.net/pages/active-x-over/dsp-6-digital-speaker-crossover.php http://www.tnt-audio.com/sorgenti/reckhorn_dsp6_e.html Currently selling new on Amazon for $399. $175 shipped to conus, including PP fees. Mike
  8. SOLD: Line Magnetic Mini 218ia

    Purchased from original owner in 2013. Very clean, very compact SE EL84 integrated. A hefty 3 watts output, 4 and 8 ohm speaker taps, 1 input, volume control, headphone/speaker switch, IEC C7 power cord. You will get the original Line Magnetic EL84s and 12AX7s, as well as Genalex re-issue N709/EL84s and ECC83s. Original box. Purchased from an authorized dealer -- not gray market. I will also include a cryo'd C7 power cord from Iceageaudio. No cage. No manual, but here's a link to the pdf. https://www.line-magnetic.eu/images/line-magnetic/pdf/Manual-LM-218IA-MINI-web.pdf 120 Volt version. Mike
  9. AL crossovers

    Probably a dumb thought, but can a metal-cased capacitor be placed that close to an inductor? I think it's okay for other capacitor types. It's almost as if the capacitor value is higher at lower frequencies.
  10. AL crossovers

    If you reused the T3A autoformer, I believe it is set for -6db. The stock AA uses tap 4 of a T2A, I think, which is only down 3db. Maybe it is more of a dip then a bump???
  11. LCR meter ESR readings Caps

    I've had the DE-5000 for a while. Only drawback...the short alligator test leads, Bought this, hoping it would fit the DE-5000, and it does. Main issue with this though, is the clips don't grip very hard and the cable is pretty stiff. But the added length comes in handy. https://www.amazon.com/gp/product/B005T710WG/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 Mike
  12. Anybody use this Mini DSP ?

    I own it's big brother, the 4X10 HD. It runs around $500, but has more outputs and physical volume control. No USB audio, though. In fact, I'm testing my almost completed Lxmini's with it now .
  13. Type A 4500 question

    Sorry if you know this already, but... The -3 db point of a first order filter occurs when the Z of the capacitor equals the Z of the driver at a given frequency. Assuming an 8 ohm tweeter, a 4 uf cap's Z is 8 ohms at 4975 hz. When a 4 uf cap is in series with a 13 uf cap, you will end up with a 3 uf cap to the tweeter. A 3 uf cap will be down 3 db around 6630 hz. The 6.8 uf cap in series with a 4 uf cap equals around 2.5 uf, crossing around 8000 hz. My point is, if the caps are in series, as you change the squawker cap you are also changing the -3 db point to the tweeter. Also, I assume you are using one for Bob's tweeters? Off to do Xmas shopping!
  14. Type A 4500 question

    I agree with the swamper idea, but very large capacitance (approx. 48 uf per channel) would be needed. Still curious about the wiring. Do you have a picture from directly above the crossover?
  15. Type A 4500 question

    I'm curious. I can't tell from the picture, but it appears that you wired the 4 uf tweeter cap directly to the crossover input. The schematic shows it wired to the output of the squawker cap, which would create a series circuit to the tweeter...constantly changing the capacitance to the tweeter as you change the squawker cap.