In article ,
Patrick Turner wrote:
John Byrns wrote:
In article ,
Patrick Turner wrote:
This also means that once the Ia travels below 10% of the idle value,
the gm of the tube cutting off
has diminished to such a low value the other tube turning on harder is
providing virtually all the Ichange x Vchange
across the available load, and is the only device coupled through only
1/2 the OPT primary
to the load, so the RL seen by this tube turning on hard has reduced to
1/2 its class A load,
or 1/4 of the nominal RL a-a, and in this case its 1.25k.
The load is the same as that for a class B amp.
Isn't 1.25k too low a load for getting maximum power from a KT88 in
triode mode, even in class B?
No.
If the RL a-a = 5k, then the class B load is 1.25k,
and if Ea = 500V, then max Ia at grid current is about 220mA.
If you run AB2, you get a heck of a lot more Ia up to around 350mA.
KT88 ca easily make 500mA, depending on loads etc.
One can get 140W from a pair in AB2 in tetrode.
But I was asking about the best load for a class B triode amp, is 1.25k
too low for a KT-88? I guess I will have to see if I can find the
triode plate curves for the KT-88, or maybe I can substitute the 6550
curves.
What is all this talk about ARC's anyone else's rules that would keep
you from handing out free copies of their abominable concoctious junk,
assuming you drew the schematic your self? You mentioned this same
issue in connection with the ManleyLabs amplifier you modified, my
understanding is that they only have protection for schematics they have
drawn, if you draw your own schematic of the same circuit, they have no
rights with regard to it. Any Lawyers out there care to comment?
I fell OK about just letting folks know what they could do
to rebuild a Manley or ARC or start from scratch and use the schematic I
will be posting
at my site.
There is nothing I can gain by posting a copy of the original schematic
these companies use.
I was not talking about the original schematic drawn by these companies,
I was talking about a schematic of the same circuit that you or anyone
else may have drawn, it is my understanding that there is nothing to
prevent you from legally posting such a schematic, illustrating the same
circuit as the company circuit, you just can't post the schematic drawn
by the company.
Many companies do NOT like ppl posting copies of their schematics on the
web,
and I have no intention of offending them by doing so.
I am not suggesting that you should do it, but it is my understanding
that they have no say in your posting a schematic you drew of their
circuit. Of course you are going to offend them by doing that, and they
may retaliate by denying you access to replacement parts.
I am free to post alternative schematics used in the cases of their amps
though,
You are also free to post your rendition of the schematic for their
original circuit. As I understand the situation they only have rights
to and control over their drawing of the original circuit, you are free
to create and distribute copies of a new drawing of the circuit that was
drawn by you.
Regards,
John Byrns
--
Surf my web pages at,
http://fmamradios.com/