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Reviews Categories | Receivers: General Coverage | Hammarlund SP-400 Help


Reviews Summary for Hammarlund SP-400
Hammarlund SP-400 Reviews: 2 Average rating: 4.5/5 MSRP: $$342
Description: The SP-400 is a superheterodyne single conversion general coverage receiver for
AM or CW from .540 to 30 MHz. There are 5 bands of which the top three have
band spread control. A wide range of selectivity is achieved using a variable crystal
filter and variable selectivity IF transformers. It includes a noise limiter and AVC.
The receiver uses 18 tubes and requires a separate power supply. Years of
manufacture were 1946-47.
Product is not in production.
More info: http://
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N8FVJ Rating: 5/5 Oct 25, 2017 08:10 Send this review to a friend
Best Ham Band AM Receiver  Time owned: more than 12 months
The SP-400 like the SP-200 is a fine AM receiver. Although single conversion, the dual tracking dual RF tube section eliminates images. It works on all bands unlike many dual RF tube receivers.

The 6K8 mixer is a better tube vs a standard converter tube or earlier similar tubes such as a 6D6. It has a dual section this a true mixer that outperforms many converter tubes.

The receiver is very quiet without an antenna attached. This is unusual for early design receivers.

Three IFs with variable tuning does a remarkable job removing or reducing the interference of an interfering station. (Usually no issues now a days with light ham traffic on AM). The 60db point is likely a 3 to 1 ratio. Not near as sharp as a crystal filter, but as good as later 50kHz IF filters.

The audio section is superior to any other ham radio push-pull designs. The SP-400 uses a 6J5 triode driving a triode connected 6F6 driver with transformer coupling to triode connected PP 6F6 tubes. Later versions use 6V6 finals. This is as good as expensive new manufacture audiophile high quality amplifiers.

The audio is so crystal clear I can decipher two stations transmitting on top of each other.

I used many other radios such as National NC-303, NC-183D, SP-600, SX-42, Collins R-648 and find the SP-400 to be the best. The SP-600 came in second place and the SX-42 is strangely very quiet on summer noise (lightning strikes, etc).

The power supply is a rock solid unit. Never seen such a heavy duty design built-in to any receiver.

If you find one of these rare receivers, buy it. You will not regret the purchase.

 
KK6IYM Rating: 4/5 Aug 15, 2016 14:14 Send this review to a friend
Wonderful old radio  Time owned: 0 to 3 months
I have just finished restoring my SP-400. When I initially applied power and turned up the volume, I thought the radio did not work. There was no sound-- even at full volume. I then touched the antenna terminal and a loud hum blasted out at me, including the sounds of a background radio station. This is quite an enjoyable radio, having very quiet reception, good sensitivity and selectivity with 2 tuned RF stages and tuned antenna circuits, and it looks great with typical Hammarlund styling. The BFO provides easy SSB reception--so lack of a product detector is not a problem. You will want to try and find a power supply. The bandswitch is quite unique--not like the rotating turret of the 600, but equally inventive. An easy radio to work on--much easier than the 600---and as good a single conversion performer as you will find.

Norm
 


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