If one needed to replace the 2x8122, it might be worthwhile looking
at the Svetlana 4CX400. The tube is spec'd for 600 watts out in
ICAS ... 1200 Watts for a pair ... with 2500 Volts on the plates.
At slightly reduced plate voltages (2200 Volts), a pair are rated
for 800 Watts CCS.
73,
... Joe, K4IK
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com] On Behalf Of Skram, Helge (MED)
> Sent: Tuesday, September 30, 2003 9:31 AM
> To: Steve Katz; 've7avv@shaw.ca'; amps@contesting.com
> Subject: RE: [BULK] - [Amps] NCL 2000?
>
>
> My advice is:
>
> Don't convert from 8122 to 4CX250b. I am aware that many get 1kw
> out of these, but the signal is not linear. The anode voltage
> will be far beyond the max spec for the 4cx250b. In the long run,
> reduced reliability will easily offset the price difference.
> The 2x8122 is designed to run 1kw output, see RCA/Burle dataseets,
> the 2x4cx250b is not.
>
>
> 73 de LA6MV
> Helge
>
> -----Original Message-----
> From: Steve Katz [mailto:stevek@jmr.com]
> Sent: 29. september 2003 16:46
> To: 've7avv@shaw.ca'; amps@contesting.com
> Subject: RE: [BULK] - [Amps] NCL 2000?
>
>
> It's a very pretty amplifier that is, of course, also quite
> old, c. 1966 or
> so. As such, if it has its original filter capacitors they should be
> replaced, along with their equalizing resistors. The 8122
> replacement cost
> is scary, but many have converted to other tubes
> successfully. One recent
> conversion we did was to create a 6m monoband amp from an NCL2000 and
> because the tubes were weak, the final conversion involved
> replacing them,
> and their sockets, with 4CX250Bs -- still puts out a kW on 50
> MHz, with much
> more available (and cheaper!) tubes. Small power supply mods
> are required
> for that, but they're easy and inexpensive. The original circuit has
> untuned input, swamped by a resistor bank. One drawback to
> most amps of
> this era, including the NCL2000, is no 160m coverage. -WB2WIK/6
>
>
> > I'm looking for comments (pro and con) regarding the NCL 2000 amp. I
> > have an opportunity to buy one dirt cheap and aside from
> the cost of the
> > 8122 tube, I'm wondering if there is anything else I should
> be aware of
> > with this box?
> >
> > 73 de Paul, VE7AVV
> > StoneyGround Station
> > -|<*><*>||<*><*>||<*><*>||<*><*>||<*><*>||<*><*>||<*><*>||<*><*>|-
> > "All email from this address is checked by Norton AntiVirus 2003"
> >
> >
> >
> >
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