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Tony D

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About Tony D

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  1. Who's ready for Kfest? We are! Please stop by our booth at the Dallas Convention Center, booth 1127, and check out our demo car. We know that we have been absent from the forum for a bit, we apologize for that. When you see our demo car you will know why, we have been locked in the lab for a couple years and we are ready to show you what we did. We will also have some SMD test equipment on display and a lab bench setup with an Audio Precision and scope. I mean this is KNOWLEDGEfest right? We are bringing some knowledge. If you know my stance on Class D amplifiers, then consider this a hint to the topic of focus. Warning: We will not have a cry closet available, please bring your own tissue.
  2. Having a second VM-1 can be a great tool. By plugging one into the 12V (lighter) outlet, you will be reading the voltage at battery/alternator basically because there is very little current flowing to the 12V lighter outlet. Voltage drop is calcuated by this formula Amps X Ohms = Volts, thus is you basically have zero amps flowing, you can not have a voltage drop, and thus you will be reading the battery/alternator voltage. HOWEVER, voltage AT your amplifier(s) can be a totally different thing. Huge currents can flow to the amplifier(s), even though the resistance of the wiring is small, it will still cause a voltage drop. I connected one VM-1 to my lighter, and one right at the amplifier's connections by lengthing the wires going to the VM-1 (you can make these as long as you like without causing any issues or voiding your warranty). With music and subwoofers, I see 0.8V - 1.2V lower at the amplifier. On the dyno I'm seeing 1.6V drop at the amplifier. 1/0 AWG is good, but it ain't that good. I am pretty confident that most people who try this will be very surprised how much voltage drop at the amplifier they have. I challange you to measure yours and post your results. By having multiple units you can check your system like this, and try to correct it by using better distribution/fuses and wiring. If you are wondering, the basic formula for how much more power your amplifier would make with different battery voltage is ((Higher battery voltage / lower battery voltage) ^2 ) x how much power you made at the lower voltage Example, I just dyno'd the T2500.1bdcp in my Jeep. It did 2365 watts into 1 ohm with the battery voltage AT THE AMP at 12.24Vdc. If I could keep 12.6Vdc at the amplifier, the amp should dyno this much power: ((12.6V / 12.24V) ^2 x 2365 watts) This works out to 2506 watts at 12.6V. Rockford rates their power at 14.4V so, clearly this amplifier makes rated power @ 1 ohm and then some. If by some act of God I could keep 13.8V at the amplifier I could get that amp to put out: ((13.8V / 12.24V) ^2 x 2365 watts) This works out to 3006 watts. Now this is only true if you have an amplifier with an unregulated power supply. Some amplifiers, like JL slash series for instance, have fully regulated supplies so this math doesn't apply. Those amplifiers will put out the same power reguardless of the battery voltage within a resonable range.
  3. Corrected version: J=(CV^2)/2 (J= joules, C=capacitance, V=voltage) for a 1 farad capacitor on a system charging at 14.2 (voltage = random number somewhere around normal car voltage I pulled out my ass for the sake of this post) J = 1 x (14.2x14.2) / 2 J = 100.82 ok lets round that to 100 ok so 1 joule = 1 watt for 1 second. now lets play with those numbers. we all know amplifiers aren't perfect, power is lost to heat, etc. a pretty common number to see is 70% efficiency at 1 ohm on a class D amp. lets say you're the typical sort of SMD person. you want bass. you want it in your face, you like the long drawn out demo music, low notes, etc.. you stive for a big, powerful system. so lets start the number game at 5000 watts, at 70% efficiency, that amp needs 7142 watts of input. and remember from before, 1 farad = roughly 100 joules = 100 watts at 1 second. 7142 / 100 = 71.42 . round it up to keep from getting bogged down. 72 so that's 72 Farads if the system was able to use the entire amount of energy stored in the capacitor, but it is not because the lowest voltage the system will hit during the amplifier's operation isn't zero volts. Let us say the system voltage drops to 10V during a burp. So then the math for the useable energy stored in the capacitor actually looks like this: Usable joules = ((farads x charging voltage ^2) / 2) - ((farads x minimum voltage ^2) / 2). So now we know the 1 farad cap in this example actually contains (((1 x 14.2^2) / 2) - ((1 x 10^2) /2)) joules. or 50 Joules that are usable. The other 50 are stuck in the capacitor and can't get out unless the system voltage dropped to zero. So actually we can only get 1/2 the energy out and thus we need 144 Farads lets keep playing with the numbers cause 144 farads is a ridiculous number for 1 second of play. say you put a nice single 275 amp alt under the hood, that charges at the 14.2 as we started this whole thing out at. wattage = voltage x amperage 275 x 14.2 = 3905 watts from the alternator bare minimum to run the car itself is say.. 60 amps or (60x14.2=852) call it 900 watts for overhead. so we got.. call it 3000 watts left for the system 7142 - 3000 = 4142 watts still needed for the system 4142 watts @ 1 second = 4142 joules / 50 = 82.84 call it 83 farads needed.. per second still haven't taken batteries into the equation here but we'll leave them out of this for now. ok so 83 farads per second, for 30 seconds of a bass race 2485 farads. So who's buying me a 2500 farad capacitor bank?
  4. Amps have caps in them, but not for that. The power supply side has basically 2 sets of caps, typically smaller value but low ESR electrolytics on the primary side of the power supply (nearest the B+ terminal of the amp usually), and then large general purpose electrolytics on the secondary side of the power supply (the high voltage side that feeds the output section). The caps on the primary side are to keep noise from the amplifier switching on and off (the power supply doesn't draw current in a continuous manner from the car, it's actually drawing pluses of current at around 50 thousand times a second) from getting into the cars electrical system from the amplifier, and also to ensure the power supply has enough energy stored up to "take a drink" once every 1/50,000ths of a second. The larger caps on the secondary side are to filter out the high voltage pulses of energy that are coming from the power supply at 50kHz and turn them into DC.
  5. This doesn't sound right, please send the unit to us as soon as possible. We will take care of it and get it right back to you. D'Amore Engineering 340 Paseo Camarillo #202 Camarillo, CA 93010 I'll get it sent out today. Should I include a note or something with the package? Just your return address
  6. Four 10 inch Pyle drivers running free-air on the back deck of my 1975 Trans Am LOL good times! This was 1987... Alpine pull out tape deck, Majestic amp, bumpin Too $hort
  7. Funny I was going to call it the Clip Detector too, but then realized it's much more than that. It will detect any distortions to the original signal. As far as input, it will work with accuracy up to 140Vrms in, which would work out to about 20,000 Watts into 1 ohm. It won't be damaged until 200Vrms+. So sure it will handle the warhorse.... i'm wondering if the warhorse can handle it Lol, what i'm saying is I don't have any experience with the warhorse personally and I don't know how clean (or dirty) the output is. It may exceed 1.0% THD long before it nears max power. I don't know this for a fact though. Just making the point that this is a Distortion meter.
  8. Steve, was just checking out your build pics with the (2) T15kW's. You are a nut. Love ya man!!! Tony D'Amore
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