2 wrote:
>>...
>>I have an amp with a pair of gg 813s with a burn in the middle of the choke.
>>
>
> ** Interesting. How many uH ? What are the lowest/first four choke
> resonances?
>
> tnx,
> Gary
>
> - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
Hi Rich,
I am pretty sure that the choke is a National R175A. It has several pie
sections on it. I think it is 145 micro henries. One catalogue says 225
but a couple of reference say 145.
Never measured resonance. Built that amp about 35 years ago. Used to run
around 3 to 3400 volts on it. I think that the choke burned when on 15
or 20 meters. I smoked a few band switch sections in it too. Although
the band switch was never really big enough.
Still have the original tubes in the amp. Couldn't kill them. It is on a
smaller power supply now. About 2300 -2400 volts. Haven't tried it on 15
meters in many years. Did have it on 20 some months ago and it worked
fine. Even with the burned choke.
73
Gary K4FMX
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