On Apr 4, 2006, at 2:26 AM, Steve Thompson wrote:
>
>
> exray@bellsouth.net wrote:
>
>> Yes there are better tubes available today...but the old 4CX250
>> family is the granddaddy of all of them. If you come across a pair,
>> and they should be inexpensive, there are many good designs which
>> have been published thru the years.
> I reckon it's also a good apprenticeship. If you encounter the quirks
> that 4CX250s can throw at you, you'll learn a lot about tube amplifier
> design. Over here, you can buy them for the price of a beer or two so
> learning doesn't have to be tearful if things go wrong.
An important precaution with 250Bs is to use a shunt regulator at the
screen so that reverse screen current can not cause a runaway condition
that destroys the tube. Also, in HF/MF service, it's not a bad idea to
terminate the grid in a R, so as to improve VHF stability. - end
>
> Steve
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
Rich Measures, 805.386.3734, AG6K, www.somis.org
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|