National Radio Company
Desktop HF Amplifier
|" 20 watts in and 1500 watts out...."||
1964 Vintage Equipment
WHAT OTHER USERS SAY ABOUT THE NCL-2000 AMPLIFIER FROM THEIR EMAILS - Thank you all!!!
I put the emails up here but I am very slow at it. Senior moments are involved!
I told Randy I thought the voltage was wrong.
But then he emailed and said the transformer was marked HI OUTPUT. So I guess that might get it up close to 3KW. Anyone seen an amp do that much? N9EFJ
|I've got another question....I have the
Peter Dahl NCL-2000 transformer in mine it does 2700 volts CW and 3400 volts
SSB.........going by the manual it loads almost 1700 watts on the low side the cw side
thats on my nye viking mb V peak meter....SWR is only 1.4 without tuner and 1-1 with tuner
it doesn't get hot or seem to hurt it...just driving it with a TS 440 with the carrier
gain set at a 4 (about 40 watts)...on HI side with no swr on 40m and 20 m...No processer
..just the MC 60....and mic gain set at a 3...very low....it actually swings off the 3kw
Is 3kw really possible out of this thing???
|Chris / N4JOY
Chris got his first amp rebuilt and then bought another on eBay recently.
These are called feedthru caps. The originals were just plastic isolators. Feedthrus caps used in lots of old gear would work. I sent Chris this link.
|Where can I get the insulated feedthrus
for my NCL-2000? I need to replace the connections into the input circuits at the tube
|KB3MJ - Denny
The Dayton motor I have in one of my amps was almost identical to the original except in size. As it was installed I can not say whether or not it was an exact replacement. But it does indeed use the squirrel cage fan. Thanks Denny for this information.
Thanks and I commend you on providing a wealth of information regarding
the NCL-2000 amp on your website.
However, I took your
recommendation on the Dayton motor to replace the original, Howard Industries model
1175-16-4065, and it is substantially different in many ways other than its size (height).
The original motor does not have a "spinning shaft"
My experience with this amp substaniates the prolonged operation of these tubes. My present amps is still going strong after several years. Altho I did the cathode mod to equalize the current draw, I still get 1300 watts out with 40 watts drive. As Ian says here his tubes have lasted over 40 years.
Perhaps using an additional supply for the filaments is a key to long tube life. The noise Ian talks about is the big thump when switching on the HV. It is very loud on my amp too.
I am beginning to think that the amps I have, have been run on AM by users that think 1300 watts out is good on AM too. Anyway I am not very active right now 11/28/07 but I will be soon. Putting up a Mosley 33 come summer. All I have now is the 80 M Loop.
|HI CARL, HAVE BEEN WATCHING UR SITE FOR THE LAST 3 OR 4 YEARS RE NCL 2000, FOUND IT VERY INSTRUCTIVE.. I BOUGHT AN NCL 2000 ABOUT 1965 SECONDHAND FOR 300 DOLLARS. THE ORIGONAL TUBES ARE STILL IN IT AFTER ALL THOSE YEARS. USE IT DAILY EXCEPT WHEN AM AWAY FROM HOME. I HAD TO MODIFY MINE WHEN I GOT IT AS WE ARE ON 230VOLT AC TWO WIRE. I USED A SEPARATE TRANSFORMER FOR THE FILIMENT . THAT IS 12VOLT AC. I HAVE A FEELING THAT IS WHY THE TUBES HAVE LASTED SO LONG. IN RECENT YEARS I HAVE A MUFFIN FAN JUST LEFT ON TOP OF THE AMP TO HELP THE AIR FLOW. I AM ABOUT TO PUT IN A SLOW START TO THE AMP TO STOP THE NOISE WHEN I SWITCH ON THE .HT. ITS JUST A RELAY ACROSS THE 220V LINE TO SWITCH OUT A 10 OHM RESISTER WHICH WILL GIVE A SMALL DELAY IN THE SWITCH ON. CONGRATS ON A GREAT WEB SITE, WILL KEEP A WATCH ON IT IN FUTURE. 73 DE IAN EI3Y|
|William Jones/W4MAJ||Dear Mr. Motsinger,
I was searching for some spare parts for my NCL-2000 linear amplifier when I came across your listing on QRZ.com. A friend of mine gave me the amplifier a couple of weeks ago. It appears to be in good working order, but I discovered a part missing and I was hoping you could help me locate one.
The part is listed as K4: Relay, Time Delay; 75 sec. delay; SPST-NO Contacts; 12 v. heater A51411
I've called a few places, but so far I've come up empty. I'd appreciate your help.
I might just have to improvise and use a newer sealed 12VAC 3PDT 10 amp
relay. It won't fit like the original but should work.
I never had a problem with the antenna relay except for the noise when it activates. I simply removed the mounting screw and that helped a little.
In my next endeavor I plan to document the wiring diagram or make a new one as Don states here. A diagram showing the wire colors would help me at least. Right around the mode switch gets complicated trying to figure what does what. Not a big deal but color coding and IDing components would help.
|I just found your sight while I was
looking for identification on a
national RF choke. I am rebuilding an NCL 2000 now myself.
value of the resistor's in the power supply section to 75K 5W instead of the 50K 5W
cutting down the heat in that section. Replacing the capacitors in the power supply with
ones from Mouser Electronics (P/N
|Ed Tanton - N4XY
I think they were 80 uf. Somewhere in the manual it states no more that 10 uf total. I did not, as I'm sure others did not too, use that amount on my rebuild.
I was browsing NCL-2000 notes today, and ran across your website. Very interesting. I have 2 of 'em. One with the stock 8122s, and one which Svetlana performed a mod to 4CX400s-intended for a magazine article that never happened. I am not a fan of such major mods, but it was already done when I traded for this one. It is a beautiful job, and if you didn't know better, you'd think it was stock. I have a tuning chart they made with settings for 80-10M incl. all the WARC bands (FWIW.)
I would be very interested in all your mods. I plan to add HC-1 vacuum relays (incl. a HV vacuum plate relay [same size as the HC-1 but w/ silicone leads] I happened to pick up) and maybe your protection circuit(s).
With all the pressure on the bands, I figure I'm going to have to get it out and set it up. Do you happen to remember the physical size of the power supply caps? I don't think it'd be a bad idea to replace them, for starters.
Use either this email address, or my home email: firstname.lastname@example.org or both.
Website (such as it is) is: www.n4xy.com . Thanks.
Technical Advisor, Implementations
KODAK Dental Systems
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Charlie amazed me by waiting 15 years to run the old horse. There are many cautions about rebuilding an amp concerning the tube GETTER. All I ever read about it says you must burn in an old setup for 24 hours before applying HV. Glad Charlie was lucky but then again he might have did just that.
These 8122's are very sensitive to abuse as Charlie says. I dropped one about 6 inches and lost it. Screen and Grid shorted. I cut it into to see the actual damage but sure enough I cut right thru the problem. I have a few shorted tubes and I'm gonna try again to cut one into.
The time delay relay can be replaced with a 555 timer circuit and I will put the circuit up here one day. If any one has the circuit, please let me put it up here for others.
I use Panasonic caps, the newer ones - much smaller. Yeah, all this talk is spurring me on to get amp #2 cleaned up and start rebuilding #3 and 4. Number 5 amp is scrap and parts. I really want to chrome the case of #2 and replace #1 in the shack. It has an old dingy green case.
Anyway, I could not find the manual and after much searching came onto your sight. Got mine going without the ski-matic, but if I had it would have helped at time. 2000 never powered time delay or so it appeaared. Thought it might have failed , so pulled and tried to find another. Haave 2-3 of similar time , but couldn't find.
So put original back in and things started working. Next problem
was relaychange-over for ant. Contacts needed cleaning and that solved that. I should have
done that in the first place , but never even thought about problems it could cause.
If you are shipping rig, it is really worth removing tubes and packing in padded container. Internal structure - especially matched types - will change with thumps.
Now a thought on using just any (working) 8122, the old '32'
transmitters used a pair of 7580's ( 4cx250 ) and what the did was provide a way ( switch
) to adjust each tubes bias to balance Ip for the tubes. If I can find a copy of the
ski-matic, I will get it to you.
Hi. I have a NCL-2000 (71 series, number 3270). Not sure of the history, but bought it from an inactive ham in Denver several years ago. He used it back in the early 90s, but it was sitting in his garage ever since. I have been using it off and on ever since with no problems. However, over this weekend I lost the HV when I went to key the transceiver. So it is now on the bench.
One of the first two things I am going to do (regardless of any problems) is to recap the power supply, and install a step-start circuit.
I was wondering if you know of a good source for the power supply caps. Mine are the original National parts, with number C-51447-1 and date code 6415. I think its about time to retire them. I was thinking of increasing the caps to 120-150 mpf. Any suggestions?
Also, if I need to replace the power transformer (I am hoping it is still good, although I am not getting any HV nor screen current - not a good sign - will be checking to see if the primary is open or if the secondary is shorted), would you know of a good source (Peter Dahl?).
Colorado Springs, CO
I been thru that scenario. It ain't a funny feeling or sight to see everything damaged, maybe blown apart.
I'm sorry but I don't do repair anymore. I am pleased to be of service to all thru the internet.......
|My NCL2000 just went down, it burned up
some caps and resistors in the screen supply and I replaced them, still won't work!
changed out tubes, still wont work. IF i cannot get it to work can you repair it for me if
Thanks Denny for this info. I have 5 amps now and I am not even active lately. But I'm gonna rebuild 2 of them someday. One does need a blower so I better get one soon because you never know when an item is discontinued.
I may have mentioned this before, but I did find a complete blower from Grainger that, with a little modification, will be as near an exact replacement as possible. The Grainger Item number is "1TDN4". The Description is "Shaded Pole Blower 115Volt". The only things needed to make it almost a "drop-in" is to carefully remove the included flange mount. (I used a small chisel to break the welds.) You must also rotate the motor on the squirrel cage housing by 90 degrees, which requires drilling of just 2 holes in the housing. With a couple of spacers to compensate for the new motor's slightly lower profile, you end up with something that actually looks original!
73 OM DE KB3MJ - Denny
|Thanks Don for this info
|FROM Don Van Horn
Hi Carl: Just acquired a
weird duck. an NCl2000 WITH A pair OF 4CX1000'S as the finals see picture
attached). Are you aware of anyone who has done this modification? The amp
is awfully dirty and will need a lot of cleaning up before I can tell to
much about what else was done to it with the exception of a string of OA2
|Thanks Roger! Glad more of these are being
Thanks for this great project. Surprisingly
there are not alot
Carl / N9EFJ
Here are some pictures of my 160 meter addition to the NCL-2000.
Works FB! With 40 watts of drive 500 out in the CW plate voltage mode and an easy 1000 when in the SSB mode at 45 watts! I back it off, save the
The photos show the padding capacitors, toroid, vacuum relays, and relay power supply. Relays were not hooked up in the photos. The front panel rocker switch has a red LED to indicate 160m operation. I also added a 0.01
cap in parallel with the 0.001 HV plate choke by-pass cap.
Jim, W4YA, was my inspiration for this project as he indicated he had done this in his e-ham review of the NCL-2000
|No doubt in my mind that the amp will last another 45 years! I sure know about that fire flying from the relay...Boy! It is very loud.....||Hi Carl!
Well, I recapped the amp and installed a new matched pair of Burle 8122
tubes. I found several resistors out of spec and replaced them. I also
built new parasitic suppressors. The amp now tunes smoothly with full
I can't believe the two original RCA 8122 tubes went south on me! they
are only 45 years old! They just didn't hold up very well, did they? :-D
Neither of them test shorted with the meter. They both seem to load ok
with normal output in the CW/low plate voltage position. When switched
to the high plate voltage position, and key the amp to set the BIAS,
BOOM!!!. Both line fuses blow and the fire flies from the plate relay.
After I replaced all the electrolytics, I tried the old tubes again with
bad results. I installed the new Burles, and BINGO!
I just wanted you to know that your web site helped me immensely.
Have a great new year!