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Most of the chatter about mods, therefore, seems to be aimed at resetting the bias point to get around 200W PEP for SSB.
Would pressing them into service for DATV be more akin to their original porpoise (Tetra)? In which case would any of the mods be necessary? What sort of power do you think you could realistically get out if them with decent shoulder levels?
I bought one of these from that seller and he was very helpful and I am very pleased with the amplifier.
It took me a little time to gather the information together and then see how easy it is to 'convert' these amplifiers for DATV.
Basically if you go by M0DTS's information you can't go far wrong.
The biasing is done in two places. You have to short one track to ground and connect the other to 5 volts which can be found on the board. You also can take out three voltage regulators. Remove one small capacitor and feed in the low level DATV signal. Connect 28 volts and switch the amplifier on with the 12 volts.
The biggest tip I would say is to scrape the varnish off the tracks before trying to solder.
I got 50watts out with DTX1 running at 100% output and nearly 10 amps from the 28volts. I had 4 amps with no signal.
I did no tuning so this probably could be improved.
I put some photos here:
Note that you need to feed the new wires in a way that you can cut out bits of the cover so it fits back down. I cut these out with my 8 inch angle grinder which is not as neat a job as could be done!
Really easy to get this amp working and really pleased with the results.