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keep_hope_alive

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keep_hope_alive last won the day on August 10

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About keep_hope_alive

  • Rank
    Acoustics Engineer
  • Birthday 08/21/1978

MORE INFO

  • About me
    love audio in all forms, circuit designing, electronics in general.
  • Name
    Rich
  • Location
    Quad Cities, IL
  • Occupation
    Acoustics Engineer / Electrical Engineer - consultant specification design engineer - i control noise and room acoustics and design electrical power systems.
  • Interests
    move electrons
  • Audio System Setup
    Alpine DVA-9861, Alpine PXA-H800, Audison LRx5.1k, Hertz MLK-165, Hertz ML3000

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  1. keep_hope_alive

    Amplifiers have no power

    You have done a good job testing and taking measurements. Thank you for your efforts to date. Remember that a voltage reading with a DMM is a relative measurement looking at the potential difference between the two points being measured. If the ground isn't making good contact with metal, you will get odd readings and low readings. open voltage at the back should match the voltage at the front. With no load, there is no voltage drop. If it doesn't match, the ground is usually suspect. Grounds will fail over time for two reasons: 1. they loosen unless you've bolted it with >1/4-20 and lock washers/lock nuts. 2. they will always corrode over time. If you sand away paint, you expose metal to oxidation and it will rust. Even if it stays "dry" there is enough moisture in the air to cause oxidation. Even if wires are touching ground, they may not be making sufficient contact electrically. I recommend cleaning/sanding your ground point to expose bare metal again. Clean/sand your ground terminal/lug. When you bolt it (not just screwed) use locking washers or lock nuts and torque it down. Lastly, silicone can help stave off oxidation (assuming it isn't already really humid when you make the connection). Additionally, make sure any ring terminals aren't loose around the wire. you should be able to pull on your connections with reasonable force (5lbs or so) and they should remain tight. Replace any ring terminals that are suspect. The same rules apply for battery connections. We usually remove amps and bench test when they are suspect. We'll even direct wire them to the battery (with an inline fuse) to test function independent of the vehicle. In your case I suspect connections.
  2. I would suspect the head unit. Do you think you could have had an accidental contact between the RCA's and the energized power wire? Even contact between the power wire and amp chassis can damage the HU since the HU shield is tied to the amp chassis through the RCA's. You can try running a ground between the HU chassis and the amp chassis or the classic Pioneer RCA ground fix to verify if you did damage the RCA shield connection inside the HU.
  3. Agreed. I usually power up an unknown amp with an inline fuse, 5A-10A is usually fine.
  4. keep_hope_alive

    Raspberry Pi-based Head Unit

    The BitOne is a nice piece, and you got an excellent price!
  5. keep_hope_alive

    LOC Use

    You can also install an RCA splitter to divide the signal after the BT receiver. Usually, a male to dual female RCA splitter is what you need for both left and right. You can also split 3.5mm stereo in the same way - one male to two female then adapt 3.5mm to RCA stereo if need be. Your idea will work but is difficult for level setting.
  6. I've tested function on many amps using a RadioShack 3.0A 13.8VDC supply. I haven't ran across an amp that won't power up and idle with it. I normally use an Astron-based power supply capable of 20-25A. It is more than enough to test basic function with music and test signals. 30A is overkill to test basic function, but never bad to have on hand.
  7. keep_hope_alive

    Raspberry Pi-based Head Unit

    Nice job doing the research. A modern car PC thread is needed.
  8. keep_hope_alive

    Need help with Sony headunit watts?.

    Quoted for notification purposes. Hopefully the info above helps. Feel free to ask additional questions.
  9. keep_hope_alive

    Need help with Sony headunit watts?.

    Here is some information about how head units are built, what those amplifiers look like, and how they are configured. Head units use a small amplifier IC (integrated circuit) to power speakers. This chip is about the size of a quarter, in total. Consider the size of an entire aftermarket amplifier and you get an idea of what expectations you should have for this tiny circuit. For example, the picture below is of a pretty standard amplifier IC in a Pioneer-made head unit. It would have ratings similar to that of your Sony. In this picture, you see the IC removed because I was making some modifications, which aren't important to this discussion. That IC does ALL of the speaker amplification for all four channels. Next, consider the topology of the amplifier IC. It already has bridged/balanced outputs, meaning there is signal on both the + and - wire. You can think of the amplifier IC like an 8 channel amp that has already been bridged down to 4 channels. For this reason, it is not possible to bridge a head unit any further. Lastly, the typical rating method of IC amplifiers (used in home or car audio) is if one channel can produce rated power for one second, they can label the IC as having the capability of producing that power into any of the four channels - even if that isn't simultaneous. Meaning your head unit can, in theory and in the right conditions, product a signal equivalent to 52W into one 4 ohm load for one second. That may not be pleasant to listen to (given distortion) but it can make it happen. Part of the problem with simultaneous power output (such as all four channels simultaneously) is power supply requirements. Consider the current required to produce the rated 216 total watts the amplifier IC is rated for, then consider the size of the traces in the amp. You'd quickly realize the traces would melt and/or catch on fire if asked to supply that much current. As such, the actual total power output of all channels simultaneously is about the amount of one channel. in your case, that is 52W divided by 4 which is about 13W per channel. Even then, distortion is high, so the typical usable (i.e. pleasant to listen to) is about 5W per channel. So why can a head unit seemingly get "loud" on speakers? Part of that relates to the sensitivity of smaller, cheaper speakers. Those lightweight cones move more easily and with sensitivities near 90dB at 1W @ 1M means that at the listening position you could achieve around 100dBA per speaker. That will seem pretty loud in a vehicle with the windows up, even if it doesn't sound very good because the amplifier distortion is high and the speakers are inexpensive or not ideally mounted.
  10. keep_hope_alive

    Best bang/buck for XM

    I have the amplifier pin-out diagrams for 2014-2018 Accords. You don't really need to put an RCA on it since it is balanced. An amp/dsp with speaker level inputs is also a balanced input - and if there is a low level sensitivity setting you get easy termination, balanced input noise rejection, and a flat response.
  11. keep_hope_alive

    Edge EDB12A subwoofer not powering on

    you connect the REM (remote) wire to the blue ANT output wire at the head unit. Normally, there is an additional blue/white REM wire at the head unit. In some cars the blue ANT wire is only active when on the Radio input (think powered antenna).
  12. Good deal. Next time you can use a DMM to check for voltage on the wires you're using. That was going to be my next suggestion. Did you notice if the wires were just in the wrong position?
  13. keep_hope_alive

    is dsp necessary

    you get more control with a DSP. you get better crossover adjustment, more EQ channels, and more precise time alignment. If you want to have more adjustment, then yes, it is worth it. if you just want the crossover flexibility, the Pioneer in network mode should do the trick. What are you using for settings now?
  14. keep_hope_alive

    deck or amp hpf

    The nice part about the head unit is the ability to adjust it while listening and also get a precise setting. I would start at the HU and adjust and listen to the change. Then you can move to the amp if you want more adjustment (meaning other frequencies), with the understanding the accuracy of the amp pot is poor but you can listen from there.
  15. keep_hope_alive

    Best bang/buck for XM

    I have a 2014 Sport. The models with the lower touchscreen are made by Alpine and have a clean, flat 3V RMS Balanced output. You just snag the signal before the factory amp.
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