[1000mp] Linear Amplifier Recommendations for Use with FT1000 Mark V

[Tom Rauch]

> But if that's really where you are, I would suggest you look for a
> really clean Drake L4B, L7, SB-220/221 or TL-922A.  The 3-500Zs are
> almost bulletproof and will coast at 600-100w output.  The only
> precaution with these older amps is that you may need to use a
> soft-switch interface of some sort, because the voltage (at least on
> the SB-220/221) is too high to be within ratings, even for the Mark
> 5's TX GND relay. I looked over the "cross-needle meter" Ameritron
> amps at Dayton last year (I think the AL-811 is one of them) and was
> not impressed with the construction -- they just looked light
> throughout, compared with the older generation of Ameritrons such as
> the AL-1200 and 1500.

The older generation amps are 1500 watt+ output amps, with 34 
pound hypersil transformers. They weigh about 70 pounds or so! Of 
course they make an AL80 series look small! They also dwarf a 
Drake L4 or SB-220.   

The AL-80B, AL800, 572, and AL811H use the same bandswitch 
as the L4B, L7 and SB-220. The voltage breakdown of the AL-
series switches is higher, because the contacts were changed and 
insulation on the support bars improved.

The 922 uses an offshore switch, and I have never tested one to 
compare. 

The transformers in the AL-80B, 800, and 572 series all are heavier 
and rated higher than the transformers in the L4B, L7, SB220, and 
TL922. The AL-series  transformers, including the 811, all have 
multiple voltage windings for power lines, allowing ~15 volt 
adjustment steps. 

The AL series (except the 811 series) have equal size tuning and 
loading caps to the Drake, Heath, and Kenwood amps, but the 
inductors in the AL-series tanks are larger.

The AL-series (except the 811 series) has step-start and inrush 
limiting, and use 7-watt bleeders across each computer grade filter 
cap and has higher total supply capacitance than any of the other 
amps mentioned. (For example, the AL800 and AL-811 use a total 
of about 55uFd of capacitance, as I recall that's almost twice the 
filter capacitance in a SB220.) 

The AL80B, with only a single 3-500Z, has more airflow than a 220 
or a L7 Drake.

Of course the AL80 uses only one 3-500ZG tube, but other than 
that 

other than tube differences, I wonder what part of the amps are 
actually smaller????     
73, Tom W8JI
W8JI@contesting.com