Vintage Radio – The Drake 2C Receiver
I have been a big fan of Drake amateur radios for years, long before I could to actually own a Drake. Over the years I have had serveral Drake radios and my favorite has been the Drake 2B receiver. Well, there is another very good Drake receiver, the Drake 2C. The 2C is a more modern version of the 2B, it has a different dial scheme, and the addition of some solid state electronics in 2C radio.
Well, I picked up a vintage Drake 2C at the Huntsville Hamfest this past August. It seemed to be fairly complete and not in too bad a shape. So I layed out some cash for the Drake and brought it home.
A bit of cleaning, some new tubes, and a tune up was all I figured it needed. I was close….but there was little detour in my plan. I started by cleaning up the radio and it cleaned up pretty well. I had been in a smokers shack, but the smoke residue was not to thick! In checking out the radio, it seemed to be basically working but it had a “lazy” AGC which is a common problem on 2B receiver. The second mixer develops secondary emissions on the grid and that loads down the very high impedance AGC line on the receiver. I ordered a set of tubes, and a new crystal for the 10/15 meter slot. Apparently the former owner wanted to be able to cover the 28.0 to 28.5 mhz portion of the 10 meter band. So they changed the crystal. That changed the 15 meter band to 21.5 to 22.0 mhz, making pretty well useless. So I ordered a new 25 mhz “stock” crystal for 10/15 and can use the 24.5 mhz crystal in the “aux” socket to cover 28.0 to 28.5. Problem solved. A slight tweek up on the tuning and the receiver was working ok.
The new tubes arrived. I plugged them in one evening and the AGC problem was gone, but the receiver was now numb as a post! It could hardly hear any signals on 75 meters on a 75 meter dipole. I put is on the generator and a -45 DBM signal was about S3 on the receiver! Very poor sensitivity. My initial thought was one of the new tubes was bad. I started swapping back the original tubes one by one. The first one I swapped, the 12BZ6 RF Amp brought the receiver to life! Trying to figure out what was going on, I saw the stencil on the chassis indicated that tube was supposed to be a 6BZ6. The kit of tubes and all the documentation with the radio indicated it was a 12BZ6. I checked the filament voltage on the socket and sure enough it was 6 volts!
Looking on the internet I found some specs on the 2C that indicated Drake changed from a 12BZ6 to a 6BZ6 tube. Oh well, even with the old tube in it, the 2C is working well! Very hot receiver!
The only thing I don’t like about the 2C is no passband tuner! WTH? A Drake radio without a passband tuner! What’s wrong with this picture!
So here is a little video, the 2C on SouthCARS, 40 meters, at about 11:00 AM in the morning. The band is starting to go away now, but the Drake is crystal clear!
The 2C sounds great!
Yeah I bet 6V on a 12V filament led to pretty poor emission.
One thing I’ve always noticed on my older radios is that the audio is better than the new “solid state marvels”. I always thought that was due to a bigger speaker and better design for it.
Then I noticed that some of them, like my KWM-2, sound like they don’t AGC on noise. They wait until they have an RF signal of “a few” or maybe as much as 10 microvolts before they start turning down the gain (never measured it). Modern radios seem to AGC on noise so that the total audio power is the same.
SiG:
I have a dim memory about tubes being voltage-controlled while solid state is current-controlled and even harmonics in tubes making a mellower sound while odd harmonics in the solid stuff sounds harsher. I know you’ve forgotten more than I ever knew about this stuff… Any thoughts?
Yes, tubes are voltage controlled, transistors are current controlled. And, as I understand the tube amplifiers do have different characteristics in harmonic distortion that affects the overall sound. Also, I think the speakers used on the older radios have a big affect. But, bottom line, they just sound more mellow to me, and I enjoy listening to them. I see a resurgence in tube amplifiers for music reproduction.
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