[ARC5] My ARC-5 station on AM.

[Jim Wiley]

If you are thinking of the Eico 730 modulator, it was a 50-watt audio 
output unit.  I used one for a while in the early '60s, plate modulating 
a severely hacked DX-40.  Worked well.

The only thing left of the original DX-40 was the basic RF circuitry.  
Power supply, modulator, and VFO all were external.

The DX-40 had suffered a transformer failure, so I built a complete 
substantially more robust external power supply with regulated B+ for 
the oscillator/driver stages.   I used a HG-10 VFO,  the Eico 730 
modulator, and rack-mounted the whole thing.  Ran the poor old 6146 PA 
tube rather harder than it was designed to do, approximately 100 watts 
DC input (plate modulated AM)  to the single tube, but it never quit.   
Finally scrapped it out when I moved to Alaska in 1963.

It was my "high school" rig,   paired with a Hammarlund HQ-150 receiver, 
set up in the attic of my parents home in California.

- Jim, KL7CC




On 2/22/2015 7:00 PM, Kenneth G. Gordon wrote:
> I have one of those 30 watt  modulator/audio amps made by Eico (I
 > think) which I got several years ago. The thing is essentially new.
 >
 > I may give that a quick try with one of my hacked-up jobs.
 >
 > Ken W7EKB
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