[Hallicrafters] DD-1 Audio amplifier


Carl km1h at jeremy.mv.com
Fri Feb 24 21:39:05 EST 2012


----- Original Message ----- 
From: "Richard Knoppow" <1oldlens1 at ix.netcom.com>
To: "Lloyd Godsey" <kk7iz at cox.net>; "'Carl'" <km1h at jeremy.mv.com>; 
"'rbethman'" <rbethman at comcast.net>; <hallicrafters at mailman.qth.net>
Sent: Friday, February 24, 2012 9:05 PM
Subject: Re: [Hallicrafters] DD-1 Audio amplifier


>
> ----- Original Message ----- 
> From: "Lloyd Godsey" <kk7iz at cox.net>
> To: "'Carl'" <km1h at jeremy.mv.com>; "'rbethman'" <rbethman at comcast.net>; 
> <hallicrafters at mailman.qth.net>
> Sent: Friday, February 24, 2012 5:13 PM
> Subject: Re: [Hallicrafters] DD-1 Audio amplifier
>
>
>> Not to mention the Hammarlund AN/FRR-12
>>
>> Thanx
>> Lloyd Godsey KK7IZ
>> kk7iz at cox.net
>> 480-620-7145
>> http://www.lloydsdipsydumpster.com/
>> http://antiqueradioarchives.com/
>>
>>
>> -----Original Message-----
>> From: hallicrafters-bounces at mailman.qth.net
>> [mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of Carl
>> Sent: Friday, February 24, 2012 4:09 PM
>> To: rbethman; hallicrafters at mailman.qth.net
>> Subject: Re: [Hallicrafters] DD-1 Audio amplifier
>>
>> National had  a diversity model of the NC-183 around 1947 and 
>> Hallicrafters
>> SX-28's were used during WW2.
>>
>> National also built big racks full of special diversity receivers under 
>> some
>> FRR-nn contract.
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message -----
>> From: "rbethman" <rbethman at comcast.net>
>> To: <hallicrafters at mailman.qth.net>
>> Sent: Friday, February 24, 2012 4:21 PM
>> Subject: Re: [Hallicrafters] DD-1 Audio amplifier
>>
>>
>>> Long before the SP-600-JX series, there was a Northern Radio Diversity
>>> version of the SP-600 J-11(No X), that was on a Navy '51 contract.  It
>>> required two receivers and also the Northern Radio LMO to keep both
>>> receivers in sync frequency wise.
>>>
>>> I've got one, I've seen a few others.  One could select either the
>>> internal LO or the external LMO.
>>>
>>> Bob - N0DGN
>
>    Somewhere I've seen pictures of modified Super-Pro receivers in double 
> or triple diversity systems. Equipped with means for an external LO. All 
> the modifications are fairly easy to do.
>    My BC-779 had been modified at some time for a crystal oscillator. It 
> had been removed when i got the receiver but the holes for the knobs over 
> the main tuning dial were still there as was a hole in the top cover of 
> the tuning unit just over the main tuning capacitor for the LO. Very 
> similar arrangement to the SP-600-JX. Mine did not seem to have been 
> modified to bring out either the AVC, IF or detector so perhaps it was 
> simply a switchable fixed frequency receiver.
>     BTW, the Super-Pro has an interesting audio amp, a Class-B or near it 
> amp using triode connected 6F6 tubes and, like the DD-1 with an interstage 
> transformer. The audio quality is very good.


Good for voice and lots of bass but the high end is nothing spectacular. Ive 
compared my SP-400 into a quality 12" modern coaxial speaker with my 1947 
Scott 800B and its PP 6L6G's into the original 15" Jensen coaxial job. There 
is no comparison as the curves show for both but they were designed for 
completely different markets and I enjoy both.

Carl




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