[HomeBrew] Ameco AC-1 replica notes and questions (hum Problems)

[Durwydd MacTara]

Suggest You either use DC for filamentnts or twisted pair for hum 
cancelation.



  Dedicated to building from Scratch!
             Durwydd MacTara





>From: kwylow zinjanthropus <catman351@yahoo.com>
>To: homebrew@mailman.qth.net
>Subject: [HomeBrew] Ameco AC-1 replica notes and questions
>Date: Fri, 27 Dec 2002 14:45:27 -0800 (PST)
>
>** HOMEBREW REFLECTOR - Please do NOT cross-post messages to multiple 
>mailing lists on the "To:" or "CC:" line of the e-mail message. **
>
>
>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.
>
>
>
>---------------------------------
>Do you Yahoo!?
>Yahoo! Mail Plus - Powerful. Affordable. Sign up now
>
>--- StripMime Report -- processed MIME parts ---
>multipart/alternative
>   text/plain (text body -- kept)
>   text/html
>The reason this message is shown is because the post was in HTML
>or had an attachment. Attachments are not allowed.
>Please post in Plain-Text only.---
>_______________________________________________
>HomeBrew mailing list
>HomeBrew@mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/homebrew


_________________________________________________________________
Add photos to your e-mail with MSN 8. Get 3 months FREE*. 
http://join.msn.com/?page=features/featuredemail&xAPID=42&PS=47575&PI=7324&DI=7474&SU= 
http://www.hotmail.msn.com/cgi-bin/getmsg&HL=1216hotmailtaglines_addphotos_3mf