[R-390] 390A versus 390

[bernie nicholson]

Hello Bob my preference is for the 390A for the Following reasons :    the 390 is in concept a much earlier design ,It uses older  noisier tubes ie. 6aj5 , 6Bj6  ect  it has 2 rf stages and an extra IF.  stage to achieve the same result as a 390A the 6082 regulator tubes are very difficult to source and VERY expensive it uses more power and gets quiet HOT ,on the plus side it has lovely audio if you are into AM listening , The 390A was initially a money saving exercise But coming later a NEW generation of tubes had arrived on the scene NOT to mention Mechanical Filters , I am into SSB and the combination of stopband attenuation and Shape factor of the 2KHZ filter are second to none as far as the Signal to noise on ssb are concerned , I have product detectors in all my receivers Fitted where the 3tf7 used to be, If you are running either of these receivers from a stable mains supply the current regulator is totally unnecessary , and the resistor substitution or in my case the use of 12BA6 tubes in the bfo&vfo is fine after the set has been on for about 40 mins. it is very very stable , on the subject of Vfo s  the best one By far is the COSMOS as you can linearize it every 25KHZ and WITHOUT DISASSEMBLY ,  My experience with Progesteron /Collins /Motorola , Have been successful But at enormous cost in time and Effort , making a Ten Turn Jig and using reams of Graph paper , the COSMOS took less than an hour and maintains its Cal within 200Hz   across the 10 turns , Regarding the 391 This Rx is electrically the same as a 390 But can be remotely controlled with the 10 position Autotune mechanism that's the only difference , On one of my receivers I  have replaced the 2&4 KHZ filters with separate USB&LSB filters and using a 455KHZ crystal  in place of the bfo  Stolen from inside Z5 coil can  , It works superbly , SSB signals just demodulate beautifully , I  obtained my first 390A in 1978  so my experience with these radios goes  back a way !!  But I am still learning .---- Original Message ----- 
  From
  Hi Bernie - Wow, I'm impressed.  Sounds like you like the radio as is.
  what is your preference, R390, R391 or R390A???? Regards, BobW