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  1. #1
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    Mods - PWM vs not

    Hi all,

    In my research I've found a couple of things that are really working for me and looking to tweak things a bit, which brings me to Pulse Width Module (PWM) devices. I get what it is and see lots of various forum comments for and against.

    For me mech mods aren't somthing I'll be jumping into anytime soon, few reasons but main one is safety related. I don't want to sub-ohm either, 1.6-1.8 seems to be more than good enough for me at the moment.

    Currently my main mods are all PWM devices, I like them and they're working for me currently but I'm curious about the difference I'd see from something that has a clean output.

    I've seen the spec's on DNA20 devices and they kinda interest me (not 100% yet for a couple of reasons), I've seen some references to other boards but searching the name of those boards hasn't got me much info on what mods use them. Also I prefer tube mods for the sonic screwdriver/lightsaber look .

    I've seen that the Provari can do pretty much everything I want, except it's not VW. I get that VV and VW are just two sides to the same equation, but VW sticks in my head better so I'm discounting the Provari for now.

    Any other devices besides something like the futura that I should look at?

    Cheers

  2. #2
    AVF Regular
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    You can set a Vamo to RMS which is a clean(er?) output. Also has vv/vw and is dirt cheap.

  3. #3
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    Cheers Quom, I've refined my google-fu tonight and starting to consider a semovar as looks to be what I'm after, couple DNA20 devices look interesting but I have concerns over the lower end settings (my preference right now appears to fall into the 7-10 watt settings, but would like some lower margin which DNA20 doesn't provide)

  4. #4
    Senior Member
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    Quote Originally Posted by Quom View Post
    You can set a Vamo to RMS which is a clean(er?) output. Also has vv/vw and is dirt cheap.
    Sorry pal but this is wrong. RMS is the measurement of the signal being output. Changing between Average and RMS only affects the interpretation of the output power setting. It has nothing to do with the output signal waveform other than vary the duty cycle slightly. It's still PWM signal.
    5 out of 4 people don't understand fractions

  5. #5
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    Okay I probably used the wrong words. RMS will give you the same effect as a provari, 3.0 volts will hit like 3.0 volts rather than feeling like 4 volts.

  6. #6
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    All (?) the Chinese mods use a PWM chip that runs at about 33.3Hz... meaning it switches on and off 33.3 times a second. At this frequency it's actually audible (the infamous "rattlesnake"), and for some people noticeable in how a device vapes (although I question this). The Provari uses PWM, but at a significantly higher frequency (100-120Hz??), plus I think it may also have smoothing implemented as well. This means that it just about puts out a flat DC signal.

    At the end of the day, personally, the rattlesnake sound doesn't get to me, and I'm more than happy to continue using the 33.3Hz chips. They don't seem to hit any harder than a flat signal. The thermal inertia present in the coils would largely negate any coarseness in frequency.

    I think your main options at the moment are:
    • DNA20-based mods
    • Nivel-based mods
    • 33.3Hz Chinese mods
    • Buck-boost converter mods

 

 

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