[AMRadio] 51J3 or 75A3?

W5OMR/Geoff w5omr at satx.rr.com
Sun Mar 5 21:48:12 EST 2006

wa1zuf at juno.com wrote:

>Indeed, the HQ-1XX lines are confusing and HQ's prior to the 160 are also reported to have outstanding AM sound. 
>The HQ-160 was the High End of their General Coverage receivers from 1958-60. At the same time the HQ-145 was also available. (1959-61). And Just to further confuse the issue, the HQ-145A ran from 1966-1969. 
>Based on my read of the specs and difference of the HQ receivers I have tried that came after the HQ-160. The 160 was probably that last one to deliver (out of the box) a pleasing "fat" sound on AM. 
>The HQ's following the 160 seemed to be focused on Communications Quality sound. This may have been a concession to SSB performance.
>I have noted that the HQ-180A's command a very high price in that "E" auction place and I will admit I have not heard one, however if the audio on the  HQ-180A is anything like my HQ-170A, the 160 was indeed the last of Hammerlund's great AM receivers. (the 170a is Ham Band only and the 180A is General Coverage)
>The source of production dates used was Fred Osterman's "SW Receivers Past & Present" 2nd edition.

That makes sense.  I bought an HQ-170 at a hamfest, because John/WA5BXO 
has an HQ-145 that I just 'adore' the sound of.  Sure, it's a simple 
output transformer on the back (I believe) from 600 ohm down to 8-ohm, 
but there's -plenty- of audio to drive that big 16" woofer he's got 
under the console to make everyone sound as 'disgustingly natural' as 
posible. The 170 (that I had) had a 'maximum' of 3kHz bandwidth.    How 
narrow and mechanical it sounded. (blech!)

I hate the thought of doing any modifications to any of my SX-73's, but 
if I was to make one, it would be to change from single to push-pull 
output 6V6's.

Thanks for the post.  That helps me a lot.

73 = Best Regards,

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