[Amps] Handbook Amp and Homebrew 8877

[W7RY]

Hey Tom...

I have been making my own with sheet aluminum and aluminum angle. I get the aluminum from: http://www.metalsupermarkets.com/ I see that you're in Uruguay. Surely there is a place to get sheet aluminum?

I get the aluminum plates cut to size and then use the angle to hold it all together.  Take a look at WD7S's amplifiers. This is how he does it. Takes a little time but it's easy and you can get good results.

You can also get stuff from Byres Custom Cabinets: http://home.flash.net/~k3iwk/  My home brew 3cx800 amp cabinet is from them. Please see: http://home.centurytel.net/w7ry/ for my home-brew 3cx800 amp and how it's constructed.


I can send some pictures of my current project with the 8877. I have the power supply built and am working on the layout of the rest of the amp. This amp will have a separate power supply and I'm going to use vacuum variables. I ordered the exact same band switch that Jerry used in his amp. I also have the tank coils and toridal coils wound for the 80 and 160 meter tank. I also have the L- coil ready to wind. I'm using the WD7S tuned input module. I tried to use the LDG auto tuner in my 3cx800 amp and did not like the way it worked so I used the WD7S module in that too. I did use all variable caps (type 30M) for the tuned input module for both amps. I got them from RF parts. http://www.rfparts.com/caps_trimmers.html  I like to use variable caps for the tuned input because I can make adjustments if I want. with the windings of the toriodial coils of the tuned input as WD7S shows in his instruction sheet, I can get the input match to the tube 1:1. 

Good luck and I can send you some pictures when I get a chance. Email me any time with questions about your project. You can also call me on the phone too. I travel for work during the week but usually I'm around home on the weekends. BTW if you bought the handbook, the CD that comes with it has high resolution pictures of Jerry's amp that you can really see much more details that is shown in the book itself. Also be sure to download the updates to his original article on the ARRL web site. I think the later versions of the handbook had the corrected info but I'm not sure.

73
Jim W7RY



  ----- Original Message ----- 
  From: TMorton 
  To: W7RY 
  Sent: Tuesday, September 09, 2008 11:28 AM
  Subject: Re: [Amps] Handbook Amp?



  Hi JIm
  Tnx for the info...I had looked at the spec sheet for the two tubes and 
  saw where the A7had both grounded grid and grounded cathode and assumed 
  that values would be different. Found the WD7S site, lot of links and 
  his offerings look pretty good...where are u getting the cabinets? I 
  went to the Buckeye site and they no longer offer the exact sizes K8RA 
  referenced in his article.
  73
  Tom

  W7RY wrote:
  > I'm doing exactly that.  There is no need to change the values. The 
  > plate load impedance is determined by plate voltage and plate current, 
  > not by the tube you use.
  >  
  > I have elected to use all the items offered by WD7S for metering, high 
  > voltage and tuned input. Do a Google search on his call and you will 
  > find his site.
  >  
  > 73
  > Jim W7RY
  >  
  >
  >     ----- Original Message -----
  >     *From:* TMorton <mailto:cx7tt at 4email.net>
  >     *To:* amps at contesting.com <mailto:amps at contesting.com>
  >     *Sent:* Tuesday, September 09, 2008 4:50 AM
  >     *Subject:* [Amps] Handbook Amp?
  >
  >     Hello,
  >     I am looking to build the 3cx1500D7 amp from the 2006 Handbook but
  >     would
  >     rather use the 3cx1500A7 tube. Does anyone have a revised
  >     schematic with
  >     values?
  >     Electronically challenged,
  >     73
  >     Tom
  >     CX7TT
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