[Elecraft] K3 audio output v headphone sensitiviy

[Brian Alsop]

 From the K3 manual page 20
"Sterero or Mono 16 ohm min. recommended"

32 ohm earphones are quite common.  Not surprising 16 ohms is the 
paralleled configuration of the two 32 ohm individual ear sides for mono.

I first ran into 32 ohm earphones for an FT1000MP.

73 de Brian/K3KO

WILLIS COOKE wrote:

>I have not heard of 32 ohm impedance headphones.  The
>DC resistance is not the impedance, but a 600 ohm pair
>might have 32 ohms resistance measured with an ohm
>meter.  Of course, I don't know what the British
>military used.  The US used 600 ohm.
>
>Measuring several headsets resistance of the headsets
>in my shack shows all kinds of resistances.  Some
>Realistic (Radio Shack) stereo 8 ohms show 9 ohms with
>the stereo speakers wired in parallel.  A Sony Walkman
>stereo headset measures 30 ohms on each speaker.  A
>Heil BM10 measures 32 ohms for each speaker.  A Heil
>Pro-Set shows 215 Ohms on each speaker.  A Telex Model
>A610-1 Military Surplus mono headset labeled 600 ohms
>measures 285 ohms.  A Telex A1210 mono headset to FAA
>Spec TSO C57 measures 615 ohms.  All of them work OK
>with my TS-850 without major audio gain adjustments
>from the speaker.
>
>Cookie, K5EWJ
> 
>--- David Cutter <d.cutter at ntlworld.com> wrote:
>
>  
>
>>They are 32ohm: don't know if the ear pieces are
>>wired in series or 
>>parallel.  Didn't observe the manufacturer, but I'll
>>get back to them in a 
>>couple of days and let you know.
>>
>>David
>>G3UNA
>>
>>
>>----- Original Message ----- 
>>From: "WILLIS COOKE" <wrcooke at flash.net>
>>To: "David Cutter" <d.cutter at ntlworld.com>
>>Sent: Monday, July 14, 2008 5:26 PM
>>Subject: Re: [Elecraft] K3 audio output v headphone
>>sensitiviy
>>
>>
>>    
>>
>>>The aircraft headphones are probably 600 ohm
>>>impedance.  Most ham headphones are 8 ohms.
>>>
>>>--- David Cutter <d.cutter at ntlworld.com> wrote:
>>>
>>>      
>>>
>>>>It has recently astonished me just how deaf some
>>>>headphones are.  In my work
>>>>I was given aircraft headphones that needed 2W to
>>>>get the same audio output
>>>>as our own make that needed about 20mW.  That
>>>>        
>>>>
>>quick
>>    
>>
>>>>test with the spl meter
>>>>needs to be repeated on a calibrated jig and I'll
>>>>        
>>>>
>>be
>>    
>>
>>>>taking my ham phones in
>>>>to get them checked.  I'll post the results here.
>>>>
>>>>David
>>>>G3UNA
>>>>
>>>>
>>>>
>>>>----- Original Message ----- 
>>>>From: "Jim Brown" <jim at audiosystemsgroup.com>
>>>>To: "Elecraft Reflector"
>>>>        
>>>>
>><elecraft at mailman.qth.net>
>>    
>>
>>>>Sent: Monday, July 14, 2008 8:01 AM
>>>>Subject: Re: Re: [Elecraft] K3 #1037 in IARU
>>>>        
>>>>
>>contest
>>    
>>
>>>>        
>>>>
>>>>>On Sun, 13 Jul 2008 16:49:25 -0700, Fred Jensen
>>>>>          
>>>>>
>>>>wrote:
>>>>        
>>>>
>>>>>>Slightly different subject, I wouldn't mind at
>>>>>>            
>>>>>>
>>all
>>    
>>
>>>>if the K3 had more
>>>>        
>>>>
>>>>>>audio available in the headfones from both the
>>>>>>            
>>>>>>
>>>>monitor and sidetone.
>>>>        
>>>>
>>>>>Fred,
>>>>>
>>>>>There's an AF Gain setting in the Config Menu.
>>>>>          
>>>>>
>>>>Check that it's set to
>>>>        
>>>>
>>>>>"HI."  If you need more, maybe I can help you
>>>>>          
>>>>>
>>find
>>    
>>
>>>>headphones with higher
>>>>        
>>>>
>>>>>voltage sensitivity.
>>>>>
>>>>>Jim
>>>>>
>>>>>
>>>>>          
>>>>>
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>>>>        
>>>>
>>>Willis 'Cookie' Cooke
>>>K5EWJ 
>>>      
>>>
>>    
>>
>
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