Volume control location for Gentex SPH 4

Gizmos and gear used in Helicopter Op's
Hover Nation
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Volume control location for Gentex SPH 4

Postby Hover Nation » Mon Jan 23 2012, 10:12

Hey all.

I purchased a CEP kit and volume control for my helmet and now it's time to install it. The issue is I don't know where on the helmet is a good place to put the volume control. I've got the output for the cep on the right ear cup. If you have got a volume control on your sph 4, can you please post photos of where it is on the helmet and if it a good place.

Cheers
Zabar
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Re: Volume control location for Gentex SPH 4

Postby Zabar » Mon Jan 23 2012, 10:31

I have the volume knob just behind the left ear cup, in about the same position relative to the ear cup as the CEP connection is to the right cup. On the left seems to be convenient for adjustment with removing left hand from the cyclic. Also made it fairly easy to wire in to the speaker wiring in the left cup.
Hover Nation
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Re: Volume control location for Gentex SPH 4

Postby Hover Nation » Mon Jan 23 2012, 10:40

Mind my ignorance but how does that change the volume on right speaker. Are the two connected??
Zabar
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Re: Volume control location for Gentex SPH 4

Postby Zabar » Mon Jan 23 2012, 10:46

Yep, adjusts volume of both sides no problem. I don't know much about the wiring so had a colleague do it for me. I'll have a look at it at work tomorrow and try to work out the basics of how it's wired for you. If you know a friendly engineer with some radio experience they could most likely help too - for the right price.
lelebebbel
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Re: Volume control location for Gentex SPH 4

Postby lelebebbel » Mon Jan 23 2012, 11:22

Can I ask where you bought the kit?

I am looking for a volume control knob to retrofit to a helmet, but I don't need the CEP kit. Is there a parts number on the volume knob?
HELiPAD
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Re: Volume control location for Gentex SPH 4

Postby HELiPAD » Mon Jan 23 2012, 11:50

Hey guys, just thought to give heads up before I post pics tomorrow with the schematics. If you have a helmet and want a volume control and don't want to get shafted for it this is what I recommend you do:

Buy a 5K ohm Variable Resistor (You can also try a 10K but the volume gradient is quite steep - a 1K is not bad and this is what your average joe headsets use unfortunately usually just a little bit too weak) and a nice volume button, bring your change with you this is going to set you back a whopping $3.80 from Jaycar electronics.

Next get your soldering iron out, flux and your solder. I don't know if anyone else has this, but my Alpha 900 is by no means quite at all, even with the Gel seals in my opinion are even overall louder than my peltor headset. I find they block the high to medium notes much better than any headset on the market while the low frequencies are almost amplified as the helmet shell vibrates. Basically alpha/gentex/insert-your-helmet-brand-here already took you to the cleaners you may swell dampen that sound by buying one with an ANR installed. I had a problem with compatibility with mine, the ANR amplified the intercom sound by around 5-7db. Enough to make it uncomfortable for me but too silent for my copilot/student. The Alpha helmets without volume control should come standard with a predrilled volume control hole on the left. (Mine had a little space filler stud in it, just poke it out). Please make sure you consult someone who knows something about helmets (eh... not me) before you go drilling any holes as it may compromise your tinker.

Then open your headset ear cup (the left one should now have two main wires going into it. In there you should find two green and one blue wire, if the ANR was monkeyed in properly it will have some sort of a tape or heat-shrink over it. In make case the green wires go to the side of the Variable Resistor legs, while the blue gets soldered on the middle leg. The colors should be very similar to mine but may be different as I have only seen a few helmets in my time. I will post the diagram and pictures tomorrow to confirm. Mount the variable resistor inside that hole, secure it with a washer and now mount the knob. You now have a volume control and saved yourself an other mortgage on a part that really costs $3.80.
bling man
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Re: Volume control location for Gentex SPH 4

Postby bling man » Mon Jan 23 2012, 13:02

Helipad, does that resolve the issue with It being to quiet for pax/ co?
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Little Bird
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Re: Volume control location for Gentex SPH 4

Postby Little Bird » Sat May 20 2017, 23:47

G'day all,
I also have a Gentex SPH-4B and looking to mount a volume control on the helmet itself.
I understand from all the above I just need the 5K-ohm potentiometer, control knob cover and a soldering iron. I'm a bit fuzzy on the helmet wiring and just wonder if anyone has pictures or a diagram they'd care to share? A user back in 2012 said they'd post pictures but never did or at maybe they've been removed now?
Thanks
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Little Bird
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Re: Volume control location for Gentex SPH 4

Postby Little Bird » Thu Jun 29 2017, 08:29

Just wanting to give this a bump for a wiring diagram or some tips of hooking up the potentiometer.
Thanks

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