>>>My Home brew 4-1000 amplifier works great except for on thing. The power
out
>>>seems low. I believe it may have something to do with the low idling
>>>current.
>>>Plate voltage is 4,600 VDC and idling current is about 80 ma.
>>
>>Zero signal anode current - a.k.a. idling current - should be about 20%
>>of max.., or around 150mA.
>
>Accoring to Eimac specs, the idling current should be 110 mA at 5000 V,
>so I think 150 is too high at 4600.
>
110 mA at 5000 V is roughly half of the diss. rating, and it makes the
8166 more linear and easier to drive.
>>
>>>The max plate
>>>current I can load it to is 450 - 500 ma. At 4,200 VDC under load and 450
ma
>>>plate current, gets 1,450 watts out with about 130 watts drive.
>>
>>Normal drive power is around 190w with such low anode V. If you want to
>>make an 8166/4-1000A play well with low drive levels, you need 6 to 7kV
>>on the anode.
>
>I wouldn't put more than 6 kV on the anode of a 4-1000A. 6 KV is the
>maximum that Eimac specs, or am I missing something here?
>
The 6000v rating is for A-0 continuous, dead carrier. The AM rating is
5kv with 100% modulation, which means 10,000v peaks. 8166s reportedly do
ok on SSB with 7kv. However, more v means more gain, and more gain
increases the risk of regeneration above the grounded grid's self
resonant freq.
cheers
Rich...
R. L. Measures, 805-386-3734, AG6K
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