RAN Technology

"A Pair of 6V6s"


Vintage Audio 0 Comments 12/03/2018 

What more does one need to hear good audio?

Posted By: Robert Nickels (ranickels)

The first audio amplififer I made (that worked) used a single 6V6 to amplify the output of a regenerative receiver.    Ever since they've been my idea of what a good audio tube should be and with a big speaker mounted on a piece of plywood, a 6V6 will produce "room filling volume" as the magazine articles fo the day said.   But as my music tastes grew acoustic-suspension speakers and a solid-state amplifier capble of driving them took center stage.

But as is often the case, returning to our roots can be fun, as was the case when I restored a little hi-fi amp using not one but a pair of 6V6s - the model 2122 made by Bell Sound of Columbus OH.   After cleaning and recapping it sounded great, but would not make a good mate for inefficient speakers, but another trip into the storage are solved that.   A  $5 flea-market find, a Knight KN-800 12" coaxial speaker mounted on a piece of plywood that might have once been mounted in someone's rec-room wall, as was the custom at the time.   Allied Radio sold their own linke of speakers with the Knight brand (online rumors suggest they were made by Jensen) as a lower-cost alternative, but they were good speakers and quite popular.   The KN-800 sold for $45 ($370 in today's dollarettes) and the Bell 2122 went for around $55, so an Eisenhower-era audiophile would have close to a grand invested in his modest 10 watt system.   But 10 watts is plenty of power to drive an efficient speaker, and while my KN-800 sounded a little thin by itself, I found that it fit underneath one of my benches like it was made for the space, and the additional air volume behind it produced a nice improvement in the bass response.

Knight called this speaker the "Best fat the Price!" and I can't disagree.     Now you can't go buy a Knight kit from Allied but you can buy them on eBay for under $100, and one of the versions of the Bell 2122 for about the same amount, so it's pretty affordable to take a stroll down memory lane, listening to "historic mono" on a pair of 6V6s!


   The following obituary appeared in the Freeport Journal-Standard on Febr. 9, 2019.      I attended a lecture by Mr. Anderson in the late 1990s after moving to Freeport and working for Honeywell where despite being a supplier to DEC, few realized the local connection existed to the founder of what once was the second-largest computer company in the world.   Mr. Anderso...  READ MORE
- Robert Nickels (ranickels),  02/09/2019 
  

The Case of the Phantom Voltage

“When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.”
Category: Technical
A Heathkit HW-12 gave me a troubleshooting challenge the likes of which I've not seen before - or even heard of!A few days ago the transmitter wouldn't produce output, and in checking voltages and I measured -75 volts on the ALC line which should be -20.   But it corrected itself and I figured it must have been a solder splash or something that cleared by itself.  That theor...  READ MORE
- Robert Nickels (ranickels),  02/08/2019 
  

The Solvay Conference, 1927

The Smartest Photograph Ever Take
Category: Historic
The Solvay Conference, founded by the Belgian industrialist Ernest Solvay in 1912, was considered a turning point in the world of physics. Located in Brussels, the conferences were devoted to outstanding preeminent open problems in both physics and chemistry. The most famous conference was the October 1927 Fifth Solvay International Conference on Electrons and Photons, where the world’s most...  READ MORE
- Robert Nickels (ranickels),  12/27/2018 
   Put yourself in 1963...A stamp was a nickel, bread was 22 cents a loaf, and you could buy 3 gallons of gas for a buck.   The average wage in the US was $84 a week.  If you were a ham, you might have been able to build and trade your way up to a really nice AM/CW station - maybe a Valiant or DX-100 transmitter with an NC-300 or HQ-170 receiver - a huge improvement over the S-38 you s...  READ MORE
- Robert Nickels (ranickels),  12/17/2018 
  

Astro...Don Stoner's legacy

How many of these rare transceivers have you seen?
Category: Vintage Ham Radio
A recent post on the Cubic-Astro mail reflector noted the similarities between the rare CIR Astro 200 and the much more common Cubic Astro 150 transceivers.   And therein lies an  interesting story...I have done a little research on the CIR Astro 200, and the commenter was right - it is the progenitor of the Astro line we are much more familiar with as a result of Swan (already owne...  READ MORE
- Robert Nickels (ranickels),  12/09/2018 
  

The DX-60 Family

what hath Benton Harbor wrought?
Category: Vintage Ham Radio
When an engineer at Heathkit in 1962 turned his attention to designing a replacement for the somewhat flawed DX-40 novice transmitter, little would he have expected the DX-60 to remain in the Heathkit catalog for 14 years.    From the new solid-state power supply to the streamlined apeperance and dependable performace, the new transmitter was instantly popular with novices who had t...  READ MORE
- Robert Nickels (ranickels),  12/09/2018 
   Epson programmable oscillators are a good substitute for quartz crystals in many applications, but they're a bit different to use.   First, they are active devices that require DC power, typically 5 volts at 45mA.    Second, like all ICs they are easily damaged by static and voltages that exceed the design limits.   Finally they are in DIP packates that are i...  READ MORE
- Robert Nickels (ranickels),  12/08/2018 
  

Programmable Oscillators - the modern day "rock"

Cheaper and more accurate and stable than the old type
Category: Crystal Replacement
With the demise of  International Crystal in 2018, hams and experimenters lost the last US-based source of affordable one-off custom crystals.  (And the definition of "affordable" ended up over $30 each).     Sure there are some offshore sources but the reality is, manufacturing one crystal to a specific frequency is not simple or inexpensive, and all crysta...  READ MORE
- Robert Nickels (ranickels),  12/06/2018 
   My primary aim when desiging the VERSA-TR was low power transmitters, and to protect the receiver from potentially damaging voltages when transmitting. 100 watts into 50 ohms is a +50dBm signal.  I'd measured the attenuation at the receiver connector in the labe at -60 to -70 dB (depending on frequency), which means that should result in -10 to -20dB at the receiver, which should be ...  READ MORE
- Robert Nickels (ranickels),  11/29/2018 

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