Modify Old Headset or Buy New?

[ColonelKyle]

I have an old David Clark headset in excellent condition left over from my Air Force flying days. It's a model H10-76 and is still being sold today as the primary Air Force headset. My question is do I modify this headset(remove microphone & change plug) and use with my Minelab Explorer or am I better off buying a new headset made to be used with metal detectors? I need volume control on my headset and Koss headsets do not have one. Any help would be greatly appreciated.

 

[Bugar In. USA]

If you like the headset and it works ok, USE IT, chances are it is of higher quality than what you would buy, as far a volume control, pick up an inline at radio shack,and connector, they can fix you up, and will be cheaper than quality headphones, and mebbe even better

 

[ColonelKyle]

My David Clark headset has a volume control built in but I guess my main concern is that it is advertised as a "low impedance" headset. I'm not an electrical engineer but in doing some research I've learned that there is a relationship between impedance, voltage draw, and volume. Since our metal detector headsets are powered by batteries I don't want to lose detecting battery time by using a headset that draws more voltage than it otherwise needs to. The literature doesn't say what the impedance is of the David Clark headset just that it is low. I think the impedance of my Minelab Koss headset is~ 30 ohms. I believe the higher the impedance the less the voltage draw but again, I'm not an electrical/electronics engineer so there may be other factors. I'm hoping there is an electrical technician out there that can unravel this mystery, otherwise I'll just opt to buy a new metal detecting designed headset. Thanks again for any help.

 

[Bugar In. USA]

Good thinking= since there is a difference in battery life between using headphones, and not using them, I know just the amount of draw on batteries, changes with each signal- used a multitester inline while checking the different signals, quite a difference just a single beep makes-try it, very enlightning

 

[Sven]

Aviation headsets make some of the best metal detector headsets, if you can find one cheap. $300-800.00 + NEW.
Wired up as mono--150 ohms
wired up as stereo--300 ohms

300 ohms will be louder than 150 ohms. 300 ohms uses less power.

Might be better off selling your headset to another pilot, buying a new detector headset, then using the extra cash
to buy something nice.

 

[kered]

Aviation headsets make some of the best metal detector headsets, if you can find one cheap. $300-800.00 + NEW.
Wired up as mono--150 ohms
wired up as stereo--300 ohms

300 ohms will be louder than 150 ohms. 300 ohms uses less power.

Might be better off selling your headset to another pilot, buying a new detector headset, then using the extra cash
to buy something nice.

I think its the other way round, lower ohms higher volume but uses more current and too low may damage the amp

 

[Sven]

Aviation headsets make some of the best metal detector headsets, if you can find one cheap. $300-800.00 + NEW.
Wired up as mono--150 ohms
wired up as stereo--300 ohms

300 ohms will be louder than 150 ohms. 300 ohms uses less power.

Might be better off selling your headset to another pilot, buying a new detector headset, then using the extra cash
to buy something nice.

I think its the other way round, lower ohms higher volume but uses more current and too low may damage the amp

If your detector amp puts out a given amount of amplification to drive 100 ohms at a given volume. Then using 300+ ohm speakers take less
voltage than 100 ohm headset to operate at the same volume. Thus giving you extra voltage so the volume will be louder as you turn up the volume control.
I use 600 ohm speakers in my headset, they can be too loud on many detectors. I was told by a headset maker that 600 ohm speakers naturally amplify sounds
on their own. And I should change out the volume pots with different ohm value and increase the wattage to at least 1/2 watt or the wipers will eventually wear out faster
due to the overpowering of certain detector amps. I had to put a limiter in place. It actually works very nice, surface to 4" targets have a duller sound and after 4" the sound gets crisper and clean.

 

[ColonelKyle]

Thanks for all the technical information and great advice. I believe I'll let the aviation headset continue service in airplanes and buy a quality metal detecting headset, with volume control, to do my hunting with. I've learned I'm not very good with a solder gun!

 

[kered]

What is "impedance":
Also known as nominal impedance. The impedance is the AC resistance of the coils of loudspeakers and headphones in ohms. Since impedance depends on the frequency, it is always specified at a frequency of one kilohertz.

If you take a look at the offerings of dynamic headphones, you will find a very wide range of impedances. The spectrum ranges from 16 ohm headphones to 600 ohm headphones. Where does this wide range come from? And which headphones are suitable for what applications?

In order to get to the bottom of these questions, a power evaluation method must first be established. The basic task of the headphone is to convert the arriving electrical signal into sound pressure. The extent that this succeeds is described by the nominal sound pressure level of the headphones. This value (specified in the unit dB SPL) describes how high the generated sound pressure is when 1 mW of electrical power is supplied. If you take a look at the nominal sound pressure level of similar headphones with differing impedances, you will find that the value is roughly the same. That means that you need to consider the electrical power converted in the headphones in order to make a statement about the sound pressure attained.

For the following considerations, the impedance of the headphones is assumed to be real (described as resistance with the formula symbol R). This is not completely correct, but is sufficient for our purposes here.

You can calculate the electrical power converted in a resistor from the applied voltage:

P = V

 

[Sven]

We are talking about detectors and headphones now which may not be in the same category as guitars and stereo sound systems.
I'm no expert in this area but, do know sound system headphones don't always perform well with detectors and headphones for detectors don't
always make good sound system headphones, nor do either one make good aviation headphones or for telecommunications. Ham operators use
headphones with up speakers from 600 ohm to 2400 ohm ratings if I recall.

Link to some good info

I had a pile of info on detector headphones, just can't find it after reinstalling my computers operating system.
I built my headphones and love them, they work perfect for my 53 year old hearing capabilities. I also have a set of Killer Bees, like them too.
But think I can hear more subtle sounds with mine. Did find different makes of speakers will sound different...... I built mine because I didn't want to pay $120+ for the same headset that can be made for a fraction of the cost. But, to each his own. I would advise anyone to buy a headset made especially for detecting, if you can try out
different brands at your local dealer, do it. Headphone choice is just like buying a detector, you don't know for sure if it will be a perfect fit with your machine,unless you try it out.