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Ok, here is an issue I am having with my linear amp. It is an old 9 tube base amp (a PAL 750B). Wattage is normal at 750-800 watts with 2 watt drive. But recently, what is happening is that it is somehow causing frequency drift on my radio on SSB only. What is unusual is that the degree and...

These are perfectly usable amps until something major goes wrong or you need to replace the tubes. At that point, I would retire it as it will cost you alot more to fix it--especially replacing 9 tubes-- than you probably paid for it used in the first place. I use mine almost day for DX and I...

You are not missing anything. To save printing space, they simply eliminated the drawing of tubes 6-9. The schematic shows one 8950 (v1) driving two more 8950's (v2, v3) and those driving six more 8950's (v4-v9) but it only shows v4 and v5 in pic. Circuitry for the other 4 not shown is just a...

The relay sounds like it is kicking in when you switch it on, but it kills the receive when you do so. I have attached the schematic for it. Any ideas??

Thanks, I will try checking all these contacts and connectors. Appreciate the help!

To clarify, the high SWR is at the radio side, not the antenna side.

When I put my old tube base amp in line, the SWR jumps way up. This is even with it off. Any ideas what to check? Could it be a bad connection or component in the amp? Thanks,

Still Looking for Info on this Amp? Go here! Pal Electronics I emailed the guys at Firestik and they did great work tracking down the manual and schematic for this amp! Take care...

I just picked up one these 750B's I cannot find ANYTHING online about these amps! Unbelievable! No specs, no schematics, no manuals. It has 9 tubes and is super heavy. I am getting about 750 out with very low drive. Not sure if that is about right as the high switch is labeled "750"...

Does anyone have any feedback on a Thunderbolt 101 amp? How many watts does it do? What bands can it run on? I have a chance to pick up a decent looking one with 2 new tubes and haven't been able to find much on it. Thanks.