TonyD'Amore

I wanted to say last night that everyone was guessing low, but I have insider info since my monkeywrench avatar is inside that amp so I had to keep quiet. This vintage of Rockford Power Series were heavily underrated.

ridin around w that nina

The AD-1 Amp Dyno has a special mode for amplifiers that have more than 1% distortion on the output, it is the Uncertified Dyno Mode. In this mode, it ignores distortions and only looks for clipping of the signal.

ah..3 1/0awg per "1/2" of the amplifier. That makes it a little more believable.

In all fairness to this amplifier, I've never tested one so can't say for sure. Although, basic math would suggest it isn't possible. From their published data: 20kw @ 14.4V with 86% eff. = 20,000 / .86 = 23,255 watts input / 14.4V = 1615 Amps DC. / Three 0 AWG = 538A per 0 AWG. Maybe possible, sounds a little sketchy. But the devil is in the details. That efficency rating is at 4 ohms. At 1 ohm it will be around 65%. They don't mention that. Now doing the same math with real numbers we see that we would need 2136A at 14.4V. This isn't happening on 3 runs of 1/0.

Not picking on any particular brands, though I may call attention to some to show an example. Lying about your product bugs me, but when they claim to be over 15kW things get a bit personal for me. (if you know me you know why) I stumbled on a great example this morning http://www.wooferwarehouse.com/Stetsom-14K2E-Amplifier--1-Ohm-12V_p_120.html They claim 16,200 Watts at 13.8V. I can't wait for someone to dyno one of these, I'm so tried of hearing numbers like 15k, 20k, 25k thrown around like it's no big deal. I am totally confident that there is only 1 mobile audio amplifier that can play music that makes 15k+ on 13.8V. Unfortunatly in the mobile audio world today, "innocent until proven guilty" doesn't apply. The game has changed, the tape measure is here. You are guilty until provent innocent. Dyno it. Prove it.

Curious how you think these companies that grossly over rate their amps are doing their ratings. You reckon they're just making it up? Squaring maximum voltage? Simply making it up

AD-1 can definitely be used to find the difference in these cables. In some testing i've performed at one of my former jobs, I tested various cables (ofc, cca, and different blends of cca) and have seen HUGE differences.

The only exception I've ever seen is the T15kW because the power supply's ridiculous capabilities. The power supply can deliver over 200,000 watts for 1 second, or 2 million watts for 100 milliseconds. It would do 16,000+ clean and 26,000+ fully clipped

Side note: The maximum theoretical power that an amplifier could produce at full clipping (square wave) is double the clean RMS. In the real world it is usually about 30-50% more. So an amp that does 50 watts per channel clean could put out 65-75 watts clipped and distorted to hell. However, the peak SPL wouldn't increase by this same amount, if at all.

You could use clamps to calculate impedance as long as you could guarantee no clipping. Two reasons for this: 1. The number on a digital multimeter will keep increasing after clipping because it is trying to measure the average or RMS value of the sine wave. 2. Clipping produces other frequencies other than the harmonic. 50Hz clipped will generate 100Hz, 150Hz, 200Hz, 250Hz and so on. So if clipping you would be calculating some sort of average of impedances at all of those frequencies combined. As you probably know the IM-SG works well to measure your impedance at any audio frequency you desire. I measured 4.0 ohms at 40Hz on my two 12s ported box in my Jeep. Then when using clamps and burping and recording max numbers it calculated to 3.8 ohms. The difference is I was clipping when clamping. Using clamps and doing the same test but making sure no clipping resulted in 4.0 ohms, just like the IM-SG read. Gotcha that makes sense. Would it hurt the dd-1 to be reading while I am clamping so I know exactly where to stop to ensure an accurate reading for impedance? I have always used the dd-1 with no load on the amp, dont want to use it with a load and damage it. Nope, DD-1 doesn't care. You would have to use 40Hz though.

I believe we are going to do another run of these real soon. We didn't predict the demand of that piece would be so good.

WM-1 isn't out yet. Yes same thing but the WM-1, 2, 3 and such were going to be non-adjustable and calibrated in watts.

You could use clamps to calculate impedance as long as you could guarantee no clipping. Two reasons for this: 1. The number on a digital multimeter will keep increasing after clipping because it is trying to measure the average or RMS value of the sine wave. 2. Clipping produces other frequencies other than the harmonic. 50Hz clipped will generate 100Hz, 150Hz, 200Hz, 250Hz and so on. So if clipping you would be calculating some sort of average of impedances at all of those frequencies combined. As you probably know the IM-SG works well to measure your impedance at any audio frequency you desire. I measured 4.0 ohms at 40Hz on my two 12s ported box in my Jeep. Then when using clamps and burping and recording max numbers it calculated to 3.8 ohms. The difference is I was clipping when clamping. Using clamps and doing the same test but making sure no clipping resulted in 4.0 ohms, just like the IM-SG read.

TM-1 and TM-2 come with a small electronic sensor on a 18 foot long tether. The small sensor is made to be glued to any surface you would like to monitor the temperature of, or just left in mid-air to measure air temp. All you need is some cyanoacrylate glue and your are good to go.

It is similar to another product we have, the VU-DIN. It gets connected to your amplifier output (speaker terminal). Once properly calibrated, it works like an indicator of how close to maximum output your amplifier is. Like a tachometer for your engine, this lets you know when your amplifier is "hitting the redline". You can use multiple units, put one on each speaker output and monitor your entire system.

Not a reactive load, purely resistive. Which is the most difficult load in terms of delivering power. Reactive loads whether inductive or capacitive can be difficult for an amplifier to drive in terms of stability. These are tests that every manufacture should do during the design phase of an amplifier. Once the amplifier's design is set, these things are seldom an issue, and if they were an issue there is nothing a consumer would be able to do about it. Purely resistive loads, or 0 phase loads, tax the power delivery of the amplifier the most. Easy test to do at home, measure amplifier input current while burping some subs at a frequency that is produces a 4 ohm reactive load. Do the same thing on the amp dyno at 4 ohms, or another purely resistive load. You will see the input current to the amplifier at its maximum during the resistive load test.

In fairness to the dyno, it updates the "minimum voltage" it saw WHILE the new maximum power number was found. In other words if the amp being dyno'd hits clipping the power number will stop increasing and thus the battery voltage number will lock in at that power number. Even if the voltage continues to drop. If the amp isn't making any more power, the dyno quits updating the power and voltage numbers. But with all that being said, yes the VM-1 is insanely fast!

Real nice! Time to throw a rechargeable upgrade kit in it! http://damoreengineering.com/foryourtoolbox.html

Hey guys, we have posted a spreadsheet that is downloadable from our website that will perform the complicated math of calculating the T/S parameters for any subwoofer or midbass / midrange you want to measure. Save it, run it, and enable macros. Hit the start button and it will prompt you. You can follow along in the IM-SG owner's manual as you go. Good luck and have fun measuring and designing your enclosure. http://damoreengineering.com/im-sg.html

Exactly, that is a huge part of the problem for most clampers. I know the signal was clipping some because I have 7dB of overlap in the system and played a -5dB track. Just trying to demonstrate that without knowing if you are clipping, and without knowing the phase angle of the voltage and current because of the inductive/capacitive load the clamping numbers are meaningless. The dyno uses loads cause a phase angle of 0 deg and it doesn't measure anything past clipping.

Birth sheet is 1325 @ 4 ohms, 2260 @ 2 ohms, 3488 @ 1 ohm.

Changed my mind when I saw the evidence lol. Now I can do what I wanted to do when I originally thought it up, which was to put 2 caps on each of my amps. I think my thread about that is still around... We did see that they had to be as close to the amplifier as possible. Just a question, Why as close as possible? Resistance? Yes if the resistance of the wire from the capacitor to the amplifier gets close to the ESR of the capacitor you effectively have a voltage divider.

This AD-1, serial #0001 is going to be on it's way to SMD headquarters next week. I'm sure he will test all kinds of wacky situations and combinations with it. I'm excited to see those results!

One thing that might need to be clarified. The voltage readings that the AD-1 records are taken at the amplifier's power and ground connectors. The voltage at my battery was almost 1.0V higher than the voltage at the amplifier on the 1 ohm runs. Typical resistance of 1/0 pure copper is around 0.0983 milliohms per foot. In a typical install one might have 15 feet on the positive side, and an equivalent resistance on the ground side (either thru chassis or with wire). So now we have 0.0983 milliohms per foot X 30 feet = 2.95 milliohms. This amp was probably pulling 250 amps or so during testing so 250 amps X 2.95 milliohms = 0.74 volts. Then add the losses at every connection point and we've probably found my missing volt.