K2 audio and searching archives

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K2 audio and searching archives

G4JQT

Hi all and many thanks for the search tips and K2 audio suggestions.



Now I've had a good look in the archives, it seems to be a matter that comes up from time to time.

I have aligned my K2 (without any accessories) following Don Wilhelm's instructions extracted from the K2 manual, all in one place and very handy - thanks Don.

My K2 does not sound 'insensitive', just slightly lacking in audio volume.

I have looked in the archives for comparative measurements but not found any, so I made some myself.

To test audio amp performance:

With sidetone pitch set to 500 Hz I measured the following peak-to-peak voltages across the speaker on a 'scope:

Sidetone level 10 = 70mV pp; 20 = 140mV pp; 50 = 350 mV pp; 80 = 540 mV pp; 100 = 700 mV pp; 225 (max) = 1.7v pp (Note: the volume control is inactive on sidetone)

Antenna disconnected; volume turned to max, 7MHz internal spurious, FL2 selected (peaked at about 7,000.25 kHz and at or below S1) approx 220 mV pp across speaker

Volume turned to max, S9 signal from signal generator on 7050 kHz gave about  5.5 V pp and S2-3 about 2.5-3V pp.

I must admit that the S9 and even S3 signal level tests did seem to give adequate volume, so maybe I'm just used to other equipment.

Nevertheless, I hope these measurements are helpful, especially to those who think their K2 volume may be a bit low.

Thanks and regards,

Ian, G4JQT
     
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Re: K2 audio and searching archives

Don Wilhelm-4
  Ian,

Into the 4 ohm internal speaker, that 5.5 Vpp is 0.945 watts.  That is
about what you can expect from the K2 audio amplifier.  Check the data
sheet for the LM380N operated at 12 volts.

73,
Don W3FPR

On 12/19/2010 7:21 AM, Ian Liston-Smith wrote:

> Volume turned to max, S9 signal from signal generator on 7050 kHz gave about  5.5 V pp and S2-3 about 2.5-3V pp.
>

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Re: K2 audio and searching archives

Tony Estep
In reply to this post by G4JQT
On Sun, Dec 19, 2010 at 6:21 AM, Ian Liston-Smith <[hidden email]>wrote:

> ...My K2 does not sound 'insensitive', just slightly lacking in audio
> volume...
>
> Ian, thanks for your post with all the info. That's the way mine is too.
This thread has motivated me to dig into mine just to see if I can re-peak
everything, and your measurements will be helpful.

73,
Tony KT0NY
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