I once had a tube type lab grade audio power amp with a switch on both
channels to roll off freqs below 8 Hz for uses such as music so power would
not be wasted in reproducing infra-sonic signals from such as footsteps
vibrating a phono cartridge.
Not sure what benefit audio down in the infra-sonic domain has for hams but
if someone is doing something down there then please speak up as I'm sure
lots of us would be interested.
Crystal headsets would be immune to the DC.
Patrick NJ5G
-----Original Message-----
From: Rob Keijzer
Sent: Sunday, November 23, 2014 7:34 AM
To: Bill Guyger
Cc: Mike Sonn ; flexradio
Subject: Re: [Flexradio] Flex 5000A w/earbuds
There is indeed dc on the 5kA phones output.
When I plug in a headphone I hear a loud pop (almost to the
level it makes me think it'll be blown).
I asked once why on earth this is needed, and got the answer that
blocking this DC (by transformers or capacitors) would also block
the lowest audio frequencies.
I simply don't use the headphones output.
BTW: I never heard that high end audio required our equipment to run DC
through our voice coils.
Rob, PA3CNT
2014-11-23 5:06 GMT+01:00 Bill Guyger via FlexRadio <
flexradio@flex-radio.biz>:
Forgot to add grab a voltmeter and check for DC
Bill
Sent from my iPhone
> On Nov 22, 2014, at 10:04 PM, Bill Guyger via FlexRadio <
flexradio@flex-radio.biz> wrote:
>
> Heating in headphones and speakers is usually caused by D.C. coming out
of the amp. I underline usually maybe something I'm not considering
though.....
>
> Bill AD5OL
>
> Sent from my iPhone
>
>> On Nov 22, 2014, at 8:27 PM, Mike Sonn <fatfend...@sbcglobal.net>
wrote:
>>
>> Anyone else use earbuds? I've used a set for years with my Flex 3000. I
>> now have upgraded to a FLEX 5K and when I stuck my earbuds in for the
>> first time, they were very warm. I thought I had them leaning against
>> something warm in the shack, but after sitting on the desk for 10
>> minutes, they are still warm. My ear canals won't get cold, but
>> clearly, there's something strange going on here. Any ideas?
>> _______________________________________________
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>
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--
Rob Keijzer
PA3CNT
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