Palomar 300A Unicorn

[357]

Well I ran the amp and had 2 more snags.
A white wire from the meter light was touching a shorting bar on the loading cap and gave a light show. I fixed that and then the loading cap was still arcing and I seen I forgot to resolder the tank coil to the band switch. After that it works good. The preamp is not working and the meter is dead but this thing is delivering some pep, 800 watts??

Is that possible nomad? Those 6LF6's are powerhouses.

 

[nomadradio]

I have seen a legit 800 Watts PEP from a 300A.

Downhill and with a tailwind. But doesn't need to shot out of a gun.

The average is a bit lower. Your amplifier is at the high end of what I have seen.

Tubes are built to exceed the claimed performance for a reason. This reduces how many duds in a production batch fail to meet the minimum.

A different set of tubes might bust a gut to show 2/3 this much power. Variation from the best to the worst is a bit wide.

The intended use of this tube was to sweep the dot left to right on the face of a fairly large-screen color CRT. If it failed to deliver full peak current, the sides of the picture would pull inwards and make everybody look too tall and skinny.

But even if your 300A only showed 600 Watts PEP that's still pretty dern mean.

73

 

[357]

TramDR I would check those coils and run that band switch a bunch to wipe the contacts.
Mine had a coil in the front that broke away from the band switch I also made sure no wraps were touching eachother.

I think Nomad is the only person that would know any answers on the design.
Mines doing 800pep my sb220 only does 500w more so its real watts out of that box and the control grid on the drivers are isolated so make sure they arent bent over and touching ground