The Rattlesnake Effect- Why the Cheapo VV [Exception Itaste MVP] Don't Vape the Same as a Provari or DNA20D

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niczgreat

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If you check out any of the PBusardo videos and fast forward to the section where he tests the voltage output. All of the low end vv devices, the Vamo, the SVD, Zmax etc are using PWM or Pulse Width Modulation without filters.PBusardo says that you can tell because when you vape on these devices on certain atomizers they sound like a rattlesnake.

The Provari, The Itaste MVP, the DNA20D mods all have filters or are using different technology and they are outputting a straight voltage amount.

You may ask what is the difference. Well the PWM has a fluctuation in voltage that is very large and very quick, some say that you can't detect it. Some even like it better. Some say it make the atty sound like a rattlesnake and is harsher.

For example on a Vamo if you set the voltage to 4V the voltage will fluctuate between around 7v and 3v the duty cycle will be short and the ending mean is the 4v that you've set.

A Picture is worth a thousand words, I captured the top two pictures from PBusardos You Tube Review of the Vamo and the bottom from his Youtube Video of the MVP.

Picture 1 showing the 33hz chip that the Vamos Uses
pwm1.jpg


Picture 2 Showing the Voltage Wave fluctuation of a Vamo
PWM2.jpg


Picture 3 Showing the Voltage Wave Fluctuation of a MVP or Provari or DNA20D
PWM3.jpg
 
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niczgreat

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You can taste electricity? Uh, OK, whatever.
The stability of the Power wave may effect the quality of the vape.

With the PWM fluctuating the voltage goes very high then low. This effects how the coils are heated. Instead of a constant heating of the coil you have fluctuations in the heating. [Debatably] and this will effect how the juice is vaporized and possibly the quality and taste of the vape.
 

yzer

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You can taste electricity? Uh, OK, whatever.
Uh, the rattlesnake effect (for those that never experienced it) is a pulse in vapor production from these PWM APVs. It is sensed by hearing alone. The rattlesnake effect is loudest when is the power button is pressed without anything contacting the drip tip.

The rattlesnake sound is related to the 33hz chips used in the APVs, but is nowhere close to being an audible 33hz tone. The sound actually seems to cycle a few times per second. The rattlesnake has no effect on vapor quality that I can detect.

Nobody is going to see a difference in a coil glowing with DC power pulsed 33 times per second compared to a coil powered by pure DC. The same goes with vapor produced by the coil.

Unless you just don't like the sound, the rattlesnake effect is a non-issue.
 
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Rickajho

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This is a bunch of bull.You are telling me my vamo does not vape good because it's not a provari?. All i can say is that i can't tell the difference from my vamo and unregulated mods one bit and a lot of people on this forum agree.

I sure don't. I can tell if a Vamo V2 is in PWM mode or RMS mode just by the sensations in the vape. I don't have to look at the display to know what mode it's running in.
 

Rader2146

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Rader2146

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Just for the sake of clarity...there is a HUGE different between the terms PWM and a Pulsed Output. PWM is a function of the regulator; a method of controlling voltage. A pulsed output is just that; On-Off-On-Off-On-Off.

ALL modern VV and VW devices use PWM as a means to give us variable voltage/wattage, but not all of them have a pulsed output.
 

Mike.S

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I sure don't. I can tell if a Vamo V2 is in PWM mode or RMS mode just by the sensations in the vape. I don't have to look at the display to know what mode it's running in.
LOL. The only difference between PWM and RMS is how the voltage setting is mapped to the duty cycle. For any given RMS setting, there's a PWM setting which produces the same output. You're noticing a difference in the actual power, not the mode. RMS mode is more like VW (but it doesn't consider the resistance of the coil, like VW), it's logarithmic rather than linear.
 

Mike.S

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]ALL modern VV and VW devices use PWM as a means to give us variable voltage/wattage, but not all of them have a pulsed output.
That's misleading. Although most boost/buck converters use PWM input for regulation, the output of the main stage is a modified triangle wave, not a PWM square wave as is being discussed. There's also an output capacitor which makes the method used by the control loop insignificant to the output, so why even bring it up?
 
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