[Amps] Homebrew is back..

[Roger (sub1)]

On 3/28/2011 12:02 PM, Lou Spradling wrote:
> It has been several years since I have attempted to "build something",; and in
> that frame I become an (operator). A real pleasure to pursue the hobby with
> researching material for 10-160 linear amps ! and in doing so I discovered this
> reflector !! Wow, a real goldmine of experienced builders in my library'.  It's
> great.
>
> Now, my problem is trying to locate one or more Tubes 4CX1600b for a Ten-Tec
> Titan II, OR. any thoughts or suggestions as how I should approach this item. It
> is working fine but it looks like a little rework of the final area  will be
> required if I can locate a tube that I should use.?

There are people on here who know a lot more about tubes than I, but:

Unfortunately even though "The Handbook" still shows projects using it,  
the only 4CX1600B's left are the ones "a few" might have on their shelf 
for spares, or "that planned project". IOW they are no longer in production.

If you still desire a tetrode of that size or close to it, there are the 
4CX1500Bs, 4CX1000s, Chinese FU728Fs in production.  There are lots of 
surplus NOS Russian Triodes and Tetrodes available with plate 
dissipation ratings from around 800 watts to 4000. but the price on the 
good ones is going up, but still cheaper than new 8877s or 4CX1600Bs 
when they were available.  Calling them good will probably raise Carl's 
blood pressure <:-))

The field for legal limit triodes,  if you want a tube still in 
production.  8877s, 3CX and 3CPX800s as a pair, are popular, but pricey 
and available as tested pulls much more economically.  Although no 
longer made the 3CX1000A7s are still found occasionally.

The more popular tubes on here are the substantially larger 3CX3000A7 
and 4CX3000A7 (ungodly pricey socket but available used) and the YC156 
(tube with handles and no socket required) is probably the most popular. 
Any of these can easily be set up to run the legal limit plus a bit, but 
we are talking tubes that weight from around 6# to nearly 10# and about 
10" tall with about 5" diameters.

73

Roger (K8RI)