[R-390] OT: Other Radios You Like

[Sam Letzring]

I personally vote for the SP-600 and the HRO 50/60. I have a R390A- fully 
restored and operational- an SP-600 in progress, an HRO-60 with all coils 
and two HRO-50's in the process of being rebuilt. By far the HRO's and the 
SP-600 have the best audio- love to listen to the HRO- very good audio out 
of the 6V6's!

Just finished rebuilding a 1934 Zenith ( 5 bands) with push-pull 42's 
driving a 12" Jensen electrodynamic speaker! Now that's what a radio should 
sound like! Never liked to listen to SW with earphones on!

Sam

KE5IRZ
----- Original Message ----- 
From: "2002tii" <bmw2002tii at nerdshack.com>
To: <R-390 at mailman.qth.net>
Sent: Friday, February 22, 2008 7:26 PM
Subject: Re: [R-390] OT: Other Radios You Like


>I strongly agree with the SP-600 recommendation.  If you have a 390 or 
>390A, the Collins A and J series don't really bring anything new to the 
>party -- you have the best one of the breed already.  If you want another 
>Collins design, the S series may be worth considering, although some may 
>not consider them to be true boatanchors and their AM filter is a bit 
>narrow for strong-signal MW and SW broadcast use.  They are exceptional for 
>SSB and CW, however.
>
> The SP-600 is quite different from the Collins designs, and a very 
> interesting design in its own right.  There are a couple of known issues: 
> Some versions have IF output amplifiers that run the tube into severe 
> nonlinearity, which generates bad spurious responses at 910 kHz and other 
> harmonics of 455 kHz.  This is quite easy to fix.  (Put a scope on the 455 
> IF output -- if it is a nice sine wave, it doesn't need fixing.  If it is 
> distorted, I can post a good fix.)  They also need their paper caps 
> replaced.  Use 0.1 uF ceramics, like the Hammarlund engineering change 
> called for, and keep the leads short.  Don't forget the caps in the RF 
> amplifier and the tuning turret.  Much as I like Orange Drops, SP-600s 
> that are upgraded to ceramics have better spurious response performance 
> than ones where the caps were replaced with ODs.  Once these issues are 
> taken care of, the SP-600 is a truly wonderful radio.
>
> Other possible candidates are the National HRO-60 (a quirky choice, not 
> great for SSB, and you need the plug-in coils); Racal RA17/71 or 
> RA117/6117 (all scarce in the US); Hallicrafters SX-88 (very rare -- 
> one just went for nearly $5000 -- I've never seen one, so I have no idea 
> how good they are, but I very much doubt $5000 worth!); RCA AR-88 (not 
> very good for SSB, and not as sophisticated as some competitors, but very 
> fun to operate, over 100 lbs, and looks like a million bucks); Rohde & 
> Schwarz EK-07 (beautifully constructed, but performs no better than an 
> SP-600, R390, or R-390A); Siemens E-311A (very interesting design, 
> somewhat quirky operation); TMC GPR-90/91/92 (very nice radios, but not as 
> nice as the SP-600).
>
> Best regards,
>
> Don
>
>
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