[hpsdr] External speaker with Mercury

[Chris Smith]

Hi

Sorry if this offends the overly sensitive but I don't believe in bottom posting. If anyone has been following the thread, scrolling to the bottom to see the latest one-liner is a waste of time and effort and if they haven't been following the thread then it is very easy to get up to speed by working backwards.

So: rant over.

Should I think myself lucky that I haven't done any damage to my Mercury board by plugging an 8ohm speaker directly into the Line Out socket? I don't run this at anything but low/background volume as, if I hear anything interesting, I put on my headphones. Also, as the 3.5mm jack on the speaker cable is mono, I tend to push it home only sufficiently for the tip to make contact with the ring of the socket, so I'm using only one channel (L or R?).

The output is quite sufficient for my relatively quiet shack.

Cheers & 73

Chris G4NUX


On 15 Jun 2011, at 02:48, Mike F wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> The amplifier I mentioned (with URL) in my previous email also contains a gain (volume) control.  Given that the one audio slider in PSDR controls both the headphones and the speaker, I have a gain control on each.
> 
> Mike, K7SR
>> 
>> Message: 1
>> Date: Tue, 14 Jun 2011 11:25:27 +1000
>> From: Luke Steele<mail10 at barefoothorse.com.au>
>> To: HPSDR list<hpsdr at lists.openhpsdr.org>
>> Subject: Re: [hpsdr] External speaker with Mercury
>> Message-ID:<E1QWIco-0002HK-2x at apn-outbound.junkemailfilter.com>
>> Content-Type: text/plain; charset="iso-8859-1"
>> 
>> At 10:48 PM 13/06/2011 +0200, Alberto I2PHD wrote:
>>> 
>>> Which magic marketing trick can be used to justify a peak power of 150W
>>> starting from an RMS power of just 15W ?? ? ?  :-)
>>> It would take a very anomalous waveform (but perhaps contemporary "music" is
>>> shaped like that...)
>> 
>> 
>> 
>> I think the "industry" uses this term "Peak Music Power Output", which is an
>> absurd multiple of RMS.
>> Perhaps it is measured at the odd isolated transient of the waveform at the
>> most distorted extreme peak.
>> Then, some of use may claim that all contemporary music is mostly distortion!
>> Whichever audio amp you use, design plenty of RF bypassing if you intend to
>> use
>> it in a transceiver. The gain of the modules is also likely to be much higher
>> than you need too. Consider also the audio output level required. Look at
>> commercial transceivers - most have an audio output of a couple of watts. Any
>> more, and you'll not only annoy the wife, you'll annoy the neighbours!
>> Luke VK3HJ
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