Stetsom Vulcan 8K 2 ohm, DONT trust the clip light. Amp unloaded test

[@MickeyMishra]

the two methods I've used for detecting this has always been either a piezoelectric driver like bear Vince has shown and a DD-1 for my RCA outputs. With the cheap gear I test, you really do have to invest in more expensive tools since you never know what you are getting. Even with some expensive amps, its always better to be safe.

[@minus3dbintheteens60]

Barevids has a really good video in this. As you might see in this video, I use twin headunits, 1 pre amps the other. To find out how much gain I can add to the other before the input clips, I high pass a driver with a passive crossover, say at 1khz, then I play a 200hz tone. No sound should be heard, turn the volume up until the distortion passes thr filter, you have your limit

[@mistanotu8791]

116 starts to clip good to know 110 looked safe lol I got one and haven't turned it up that high yet

[@minus3dbintheteens60]

Glad you found the video useful, although remember that the amp is unloaded in this test, it isn't driving a speaker or resistor like in my other vid. So just remember that in this video, if the output start to square off at say 125v, then when the amp is actually driving a load, especially at 2 ohm full tilt, the voltage at which it starts to square off will be lower. I think if you tune it so that it can never ever exceed 125V RMS, you should be pretty OK, 125v squared, divided by 2 ohm is 7812.5W RMS, which should be pretty safe, that's as far as I'd personally take it. Also don't forget that if you tune it to 125V when the car is off and the amps input voltage is say 12.6v, when you drive and the alternator is outputting 14.4v the amp will output more than 125v. So tune the amp with the cur running and the cars voltage at maximum potential ie 14.4

[@Mr.NpK143]

Great video

[@marke.8334]

I just received the stetsom 3K today and clip the s*** out of my brand new serwinn Vegas, no clip ever came on

[@nathanshanks5478]

Square root of 16000 is 126.49. Should be your target voltage at 50hz or 40 your choice.. I would do as you suggest 122 v.

[@PowerToneAudio]

should i use a dummy load to get the correct clipping , because unloaded i believe will show you late clipping.

[@tv_you-_-tube_tv]

143v recorte distorcion. 123v onda sinusoidal perfecta. 123 x 123=15.129.... 15.129÷2ohmios= 7.564 wrms. 🧑‍🏫 Aunque se deven de testear con carga, porque al vacío suelen dar un poco más de potencia.

[@cdbennett2332]

So there is voltage present without a load?

[@minus3dbintheteens60]

Yes, voltage. Then the impedance of the subwoofer, times the output voltage gives the wattage.

[@minus3dbintheteens60]

Because its AC, there is no "constant voltage", it fluctuates up and down, so we measure the "average" of the fluctuating wave. We can easily measure the peak voltage, and we then multiply it by 0.707 to get the Root Mean Squared (RMS) voltage. Take that Vulcan 8K amp for example, ok, so I tune the amp and headunit, the headunit at max volume puts out 8v rms before any clipping, and we tune the gain so that at 8v of input, the amp is just about to clip. The amp is putting out 177v peak. What we do is times 177v by 0.707, gives us 125v. 125v rms. If we want to work out what the output power would be into 2 ohms (because this amp is only rated down to 2 ohms, at 8000w rms) and we want our result to be in Watts RMS, we times the output voltage by itself (we square it), then simply divide by the impedance. 125v x 125v /2 = 7812wrms. So, what about 4 ohms? Easy, its output voltage squared, divide by impedance. 125 x 125 /4 = 3906wrms. BUT, for a 4 ohm you would think that it would be exactly half of the power it puts out at 2 ohm right, but it won't be exactly, because the more power you draw out of the amp, the less voltage it will put out before clipping. Its called rail sag. Imagine a car battery sitting at 13v doing nothing. Now imagine the voltage, as the battery is cranking over an engine. The voltage would drop to like 11v or even 10v while it is doing the work, you can tell as the headlights dim while your cranking. Same thing is happening in the power supply of the amp, the more power it puts out, the harder the rails will sag. That's why it might only put out 50% more in to 2 ohm than it does in to 4 ohm. That's why this amp does over 5000wrms at 4 ohm, but 8000wrms at 2 ohm. The rails can sit above 145v when its only putting out 5000wrms, but when its putting out 8000wrms+, the rail voltage drops down to 125v. And so, that means that without any load attached at all, and with the highest accepted input battery voltage, it will have the highest rail voltage possible.

[@drvictoria07]

Are those 4 gauge speaker inputs?

[@minus3dbintheteens60]

Yep, i reckon you'd get 4 gauge in there, but there is only 1 set of outputs

[@tommylortz411]

How is the efficiency vs a 2 ohm md8k?

[@bjenks2]

Can I run the Vulcan 8K 2 ohm version on 1.8 ohms? My woofers read high.

[@minus3dbintheteens60]

I'd be pretty careful, I wouldnt lean on it with the engine off, if voltage at the amp NOT the battery drops under 12v while it's drawing 800 amperes then expect disaster. If voltage after vdroop is over 12.5v and if you don't clip the amp then it's probably safe. If you're careful, responsible and reasonable with expectations then it should be fine.

[@easterpink7523]

Woofers are inductors, meaning that the impedance rises with higher frequencies, when your subs are playing they don't stay at 1.8 ohms. As long as you don't play anything too low under your fs you should be fine. There are some people who run 1 ohm Brazilian amps at 0.5 ohms and have no issues, just make sure your voltage doesn't drop because Brazilian amps tend to fail at low voltages.

[@h.a.w.gfilez8902]

So this should push 2 15s no problem then

[@minus3dbintheteens60]

This would push 8x 15"s, it is a genuine 8k, but whatever you do, don't run it hard on less than 13v after droop, or it will explode like mine did. I made the mistake of burping it for around 1 second in the driveway with a 100A charger on, just to check the inrush current to decide of what size fuse to install, and I killed it. You have to keep in mind this thing will be drawing 10,000 watts or more

[@sarahconner9433]

Good Lord!! Do you know what 143 volts is?!?!!!!

[@minus3dbintheteens60]

A hell of an ass whoopin' for a single 12 🤣

[@sarahconner9433]

@@minus3dbintheteens60 a Smokey party like a nightclub in Miami!!!!

[@minus3dbintheteens60]

Especially with a square wave like that, the smoke would put Californian bushfires to shame!!

[@sarahconner9433]

@@minus3dbintheteens60 hahaha!!

[@sarahconner9433]

@@minus3dbintheteens60 what does it push into 10hz?