The AM Forum

ANNOUNCEMENT

I've purchased the AF4K Crystals business and will be returning it to service as soon as possible.

I might be ready for basic orders in the next week or two. 

The new website will be   http://www.af4k-crystals.com/


Steve WD8DAS

http://www.wd8das.net/
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This is great news, of course, but it should be mentioned that the FT-243 crystals sold previously were actually HC-49/U crystals in FT-243 shells. This can be an issue, particularly for vacuum tube oscillators that put more current through the crystals than the smaller HC-49/U architecture can handle.

True.  For example they don't do well in a simple transmitter like an AC-1 with a single stage 6V6/6L6, where they tend to chirp a LOT.  I've never managed to cook one, but high crystal currents are problematic.  However,  I've used them without any problems in other rigs with a low level crystal oscillator — DX-20, Globe Scout, Ranger, Valiant, Globe Champ, Globe King, and others.  And in those cases, they work just fine.

I've had excellent results with the modern crystals.  Thinking back, the only crystal I ever damaged in 40+ years of experimenting was an original FT-243 made in the 1970s by JAN Crystals.  It was killed by a one-tube 6L6 transmitter.  When I disassembled the crystal holder I could actually see the crack in the quartz! 

I've not had any failures of the modern crystals that I purchased from AF4K, even in similar circuits.  In any case it is wise to keep crystal current reasonable.  I've had some 6AG7 oscillators that were heating the FT-243 crystals enough to cause frequency drift during key-down.  That was likely stressing the crystal, so I modified the design to add a resistor or lamp in series to reduce the current. 

Steve WD8DAS

Great news! I have been checking the website in hopes of an update.

Regards, Rich

 ;D  Happy to have crystals to order again.

Nice that you kept the name connection with Bry.

Steve,

This is great news and I wish you the best.

Will you be fulfilling the pending orders that were made around the time Bry passed away?  (I'm one of them...)

73, Tony

Tony -  Mrs Carling has forwarded a few emailed orders to me but unfortunately yours was not among them.  I gather she was not able to access any of the website order information.

I do not yet have the new web store operational but I am eager to help you with your order if possible.

Send the details of your crystal desires to me at  orders@af4k-crystals.com

Thanks!


Steve WD8DAS

Steve:
Will your crystals be fundamental and overtone?