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!


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

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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 

VERSA-TR Panadaptor Video

Use the VERSA-TR to improve your SDR panadaptor
Category: VERSA-TR Information
An inexpensive SDR like my RANVerter Pi Plus can add a panoramic spectrum and waterfall display to almost any vintage (or modern) radio.    The ability to use the SDR as a 2nd receiver that can be tuned to a different frequency or mode from the main transceiver is a real plus, but annoying feedback and delayed audio will be normally heard through the PC speakers in the transmit mode...  READ MORE
- Robert Nickels (ranickels),  11/27/2018 
   The muting relay on the VERSA-TR can be used to control other devices when RF is present.   An example would be an "On The Air" sign, or to key an amplifier.    One specially-wired cable is required - note that no connection is made to the sleeve, which is usually the ground connection on a TRS plug.  A normally-open set of relay contacts exists between the ...  READ MORE
- Robert Nickels (ranickels),  11/13/2018 
   VERSA-TR can be used to mute conventional (non-amplified) speakers as would be used with a non-SDR receiver.    This requires the user to wire up two cables with 3.5mm (1/8") stereo plugs on one end.   Note that connections are made to EITHER the tip or ring of the connector and to the sleeve which is normally the ground return.   It doesn't matter whether yo...  READ MORE
- Robert Nickels (ranickels),  11/13/2018 

TRS (stereo audio) plug reference

3 circuit TRS, 1/8" (3.5mm) diameter plug
Category: VERSA-TR Information
Just for reference, the common 1/8" dia. stereo plug which is used for VERSA-TR speaker/audio connections.   The three connections are commonly known as Tip, Ring, and Sleeve, but are typically wired as Left, Right, and Ground in stereo audio hookups.   ...  READ MORE
- Robert Nickels (ranickels),  11/11/2018 

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