[HomeBrew] Ameco AC-1 replica notes and questions

[kwylow zinjanthropus]

All:

Just completed my Ameco AC-1 replica (just in time for Straight Key Night, WOO HOO!)

Now just a few notes for those of you wishing to construct something similar. I used a smaller more compact chassis than the original and upgraded the xmtr with a few more things:

-A BNC rf connector was used vice the old 2 lug terminal strip

-Toggle power switch instead of the old slide switch

-Phone jack is used for the key instead of the xtal tube socket

-Provisions will be made for VFO drive

-I deleted the 6X5 rectifier circuit and used a pair of 1N2007 instead

-It is fused

Power xfmr is a 520 VCT 90 mA unit coupled to two 33 uF 450 elec caps and a 2H 100 mA choke in pi filtering config. However, I had to stand off the choke on some Radio Shack insulated standoff insulators as the max voltage that could be handled by the choke is about 300 VDC. It may be precautionary overkill but I didn't want to question Mr. Hammond's engineering staff on the capability of the choke. 

Most of the parts came from Antique ES. I had trouble with making a coil with one of their 5 pin coil forms. The thing just about disintegrated under my 30 watt soldering iron's application to the pins. Luckily I had another one and that one was fine. Loads up great using a 7073 xtal I had lying around. I will be having a 30 meter coil and xtal made up for the transmitter as I would like to operate the rig on that band. I don't think my current 40 meter coil can load up that much as the plate cap is just about 90% open on 7073. The coil is now 15 tpi with #22 magnet wire.

Final question: I got some hum on my sig. It is noticeable and I have some filament power running next to the xtal line and possibly the B+ to the 6V6. Any suggestions on filtering? My current power supply 33uFx2 cap/2H filter should be sufficient, right? Let me now and thanks. Cal, N6KYR. 



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