[Amps] Solid State Amps (or rather the NCL-2000...)

[Carl]

You can also run it in the CW position for 3dB less heat (-;


Carl
KM1H


----- Original Message ----- 
From: "Manfred Mornhinweg" <manfred at ludens.cl>
To: <amps at contesting.com>
Sent: Sunday, October 19, 2014 1:17 PM
Subject: Re: [Amps] Solid State Amps (or rather the NCL-2000...)


> Carl,
>
>> There are alternatives Manfred.
>>
>> Get a pair of 8072's and some defunct 8122's.  Machine off the finned 
>> radiator and push onto the 8072.
>
> That's a good hint. I had read it before somewhere, but forgotten about 
> it. I have now stored your message in my NCL-2000 folder, for when the 
> tubes fail.
>
>> You can do this with other tubes including the 4CX250/300/350 family. Use 
>> copper pipe slit to fit to adapt the different sizes.
>
> I have a lathe, so I can actually turn adapter parts if necessary.
>
>> Ive even tried the anode cooler from shorted 3-500Z's slipped over the 
>> 8072, they actually run quite well to 1200W out since that blower puts 
>> out a lot of air
>
> Mine doesn't, because it's a 60Hz blower and here in Chile it has to run 
> on 50Hz, so the airflow is drastically lower. I compensate partially for 
> that by running the tubes at a lower idle current than normal. So far 
> people say that I'm not splattering, so it should be OK.
>
>> Convert to the Russian GS-36B or Svetlana relabled 4CX400A. Change to the 
>> Svetlana SK2A socket and a new filament xfmr. Other voltages are 
>> compatible, even the bias. It also has a much more stable screen that is 
>> not prone to current drift. Written up in the 90's by Svetlana and George 
>> Baxter, W6TC.
>>
>> Use a single 3CX800, same socket, minimum reworking. A bit tight in 
>> places but done by many.
>>
>> Get a bit creative and adapt a pair of Eimac 3CX400U7/8961 and use it as 
>> a 8874. Real cheap, even NOS as there is no replacement application since 
>> all the 800-900 mHz Motorola cell and other cavities have been retired.
>> http://lists.contesting.com/_amps/2012-06/msg00442.html
>
> When the time comes and the 8122 tubes fail, if that happens before I have 
> my final super top solid state amplifier up and running, then I will 
> consider what to do. Maybe they never fail, because I use that amplifier 
> only rarely. I'm somewhat allergic to noise, and the blower noise is 
> highly irritating to me. Not when I just switch on the amplifier, but 
> after half an hour or so of constant blower noise, I start going up the 
> walls, and shut off the amplifier. That way the tubes last long! ;-)
>
> Several years ago I installed an acoustic labyrinth at the air inlet, and 
> replaced the oil by the thickest grade that would allow it to run. The 
> noise got slightly lower, but not much.
>
> I often think that when the tubes fail, that would be the cue to get rid 
> of the noisy beast!
>
> Manfred
>
> ========================
> Visit my hobby homepage!
> http://ludens.cl
> ========================
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2015.0.5315 / Virus Database: 4181/8416 - Release Date: 10/19/14
>