I once owned an Ameritron AL-80B and was quite impressed with it performance, design and build quality. I was regretful soon after I sold it, but a few years later I decided to build my own.
I was working away from home at the time so progress was slow initially, with the metal work part of the build progressing only on the weekends that I travelled the 300 kilometres to get home and there were no other household jobs to be done once I got there. Over a period, I bought quite a few original parts that were listed in the MFJ catalogue including meters, band switch, plate choke, input tuning board etc. Suitable variable capacitors were already in my collection of parts. I studied many photos of the AL-80B available on-line to follow the RF deck layout as closely as possible. I had an original top cover so this formed the basis for all dimensions required when building the chassis.
The power supply and control side of the chassis is where I used my own ideas and physical layout. The filament transformer used was originally from a 12V PSU and the secondary was rewound for 5 Volts @ 15 Amps. The plate transformer is one from a Kenwood TL-922 so it is lightly loaded in this one tube application. This was a very time consuming project but one that I really enjoyed, once I came to terms with the fact that it was not going to be completed 'overnight'. This then gave me time to really think about the layout and associated metalwork & wiring etc. Whenever I came to a 'stumbling block', I would put the project aside for a few days to think about the next move. At one point of the construction I had concerns that I was not going to get all of the circuitry I needed into the power supply side of the chassis. I tried a number of layouts before settling on this final one. As a result of not rushing through this build I can say that only one extra and not-needed hole was drilled in the chassis as a result of making an error of judgement... A first for me!
I was working away from home at the time so progress was slow initially, with the metal work part of the build progressing only on the weekends that I travelled the 300 kilometres to get home and there were no other household jobs to be done once I got there. Over a period, I bought quite a few original parts that were listed in the MFJ catalogue including meters, band switch, plate choke, input tuning board etc. Suitable variable capacitors were already in my collection of parts. I studied many photos of the AL-80B available on-line to follow the RF deck layout as closely as possible. I had an original top cover so this formed the basis for all dimensions required when building the chassis.
The power supply and control side of the chassis is where I used my own ideas and physical layout. The filament transformer used was originally from a 12V PSU and the secondary was rewound for 5 Volts @ 15 Amps. The plate transformer is one from a Kenwood TL-922 so it is lightly loaded in this one tube application. This was a very time consuming project but one that I really enjoyed, once I came to terms with the fact that it was not going to be completed 'overnight'. This then gave me time to really think about the layout and associated metalwork & wiring etc. Whenever I came to a 'stumbling block', I would put the project aside for a few days to think about the next move. At one point of the construction I had concerns that I was not going to get all of the circuitry I needed into the power supply side of the chassis. I tried a number of layouts before settling on this final one. As a result of not rushing through this build I can say that only one extra and not-needed hole was drilled in the chassis as a result of making an error of judgement... A first for me!
Click on an image below to enlarge
Page last updated 25th August 2018
1209 Page Visits
It is planned to have the front panel labelling professionally screen printed.
