The ALH is a grounded grid linear Amplifier developed by Ameritron using low cost A power triodes. It operates in class AB2 for SSB. I’ve just been asked to fix an ALH by a local. but can’t find a Service Manual download anywhere (a main board layout would be useful). The ALH is rated at watts CW carrier in normal CW or tune. The AL is rated at watts PEP voice, or just over watts carrier.

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I’ve just been asked to fix an ALH by a local. The size of the 10 m coil has become too small due to mounting method. As radio amateur time is free and one can modify at random time. People who bought this also bought. These terms and conditions are subject to change at any time and without notice. Page 1 of 1.

I wouldn’t supersize that diode, it is a weak link for a reason as I understand it. For decadesI advise to mount a resistor and fuse in series with the anode choke as flash over protection for tubesrectifiers and transformers. The Grid current meter was reading on transmit with no drive. AC input power is removed from the transformer when the cover is removed.

Ameritron never published service manuals for any of their amplifiers so they don’t exist. The Grid Current meter provides a continuous reading of the A grid current to indicate proper loading of the Amplifier. Terms and Conditions These terms and conditions contain rules about posting comments.


Can you site some issues you think are not good and how it can be improved. Opening the amp and inspecting it showed a connection that was not soldered at the factory. My inspection yielded a burned grid resistor and a partially conductive varistor on. Used to remove the Amplifier from the RF line while filament and plate voltages are maintained during “barefoot” operation.

For half the price of a full, legal-limit amplifier, this amp is a great value and works well. The long wire to be replaced by coaxial cable RGso that the length is converted into a small capacitance in parallel with the load capacitor.

Please note that the output in the table is partly achieved by exceeding the maximum grid and anode current. The inductance of the long supply wires can not be ignored.

It is a cheapsimple and proven effective method. The only issue I had was that Meters had little output. By submitting a comment, you are declaring that you agree with these rules:. More items related to this product. I like TT gear in general, but their dual Z amp is about as “unserviceable” as any I’ve ever seen.

You agree not to post any material which is knowingly false, obscene, hateful, threatening, harassing or invasive of a person’s privacy. Given its damage in the depicted tubeI think it’s caused by parasitic oscillationswhich led to a high voltage.


Roger, you must be the only person in your area that is willing to tackle ham amplifiers with problems.

Notify me of new comments via email. I am wondering why you say the amp is awfully made.

Free Service Manuals

I soldered this to the spot on the band-switch that hadn’t been soldered, and its been flawless since. Save on Ham Radio Amplifiers Trending price is based on prices over last 90 days. What a horrible linear amplifier!

After each modification the amplifier was firmly tested and plates never becames red. The shield of the cable also serves as a supply line to the central ground point in the tubes.

Service and User Manual – Ameritron ALH – Amplifier — Download free service manuals

With this methodthe distance between S1 and C26 changed to a small capacitance in parallel with the load capacitor and the total inductance of the coil 10 m is thereby reduced. A unique “buck-boost” winding allows adjustment of primary voltages to match a wide range of line voltages centered on and volts.

My preference would be given to the latter because I have more experience with it. G3YROAug 1,