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Reviews Categories | Amplifiers: RF Power - HF & HF+6M | National NCL-2000 Help


Reviews Summary for National NCL-2000
National NCL-2000 Reviews: 14 Average rating: 4.7/5 MSRP: $600?
Description: Linear Amplifier, 80-10 meters, (2) 8122 final tubes
Product is not in production.
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DK3QN Rating: 4/5 Jun 26, 2003 12:52 Send this review to a friend
flexible and solid performer  Time owned: more than 12 months
This is really a quite flexible amp for it's days. You can drive it from low power drivers after modification. Also worked out quite fine on some WARC bands with slightly reduced efficiency.
Drawbacks: noisy fan and tubes (2 pcs. 8122) difficult to find and also rather expensive these days.
 
Anonymous Rating: 4/5 Mar 29, 2003 14:38 Send this review to a friend
Very nice amp  Time owned: more than 12 months
I had 2 of these amps in the 80's and early 90's. What I liked most was the looks of the amp. It is a very attractive looking amp compared to the cheap looking tin boxes produced today. If you can find one in very good condition and it works (has been kept out of damp basements), it should work forever, IF you run the amp at about 1kw out. Even though this amp is rated at about 1300 watts out, beating every last watt out of it will increase the chances that you will be replacing the power transformer and tubes often. Running it at 800 to 1kw will make little difference at the receive end and will extend its life significantly.

From what I can remember, if the motor bearings are in good shape, it is a pretty quiet amp. Since it had a 50 ohm resistor for passive grid input, the input Z will match solid state amps better than most amps with pi networks for input matching. The drive requirement can be reduced down to about 10 watts if the input is changed to 200 ohms fed with a 4:1 balun. I modified one of my amps this way and it worked well using a rf type 200 ohm resistor.
 
W6ED Rating: 5/5 Mar 29, 2003 13:38 Send this review to a friend
Great amp  Time owned: more than 12 months
I completely agree with K5ZP's review I have 4 of them plus a Henry 2kd5. I have installed slo-start circuits in each to prevent the loud thump on turn on. I also replaced filter caps with 68mfd 500 volt aluminum electrolytics from Digi-Key Corp. Had 1 tramsformer failure SG to HV winding short and replaced with Peter Dahl unit (still available) Have had to rebuild several band switches. Have not had good luck with 8122 pull-outs, mostly gassy with occaisional internal shorts. New tubes cost about $140, well worth the price. Pullouts cost about$70. This amp takes about 30 sec to change freqs and retume. My range of amp prices ran from $60 to $300. Had one failure of bleeder resistor, couple problems with K3 plate relay contacts. Tubes are definitely difficult to remove.
 
K5ZP Rating: 5/5 Feb 26, 2001 18:44 Send this review to a friend
Ahead of it's time and still a great value  Time owned: more than 12 months
I'm an NCL-2000 junkie. They are great looking and perform above my expectations. I've personally owned five of them and have had two additional 2000s on my workbench. I currently only own three NCL-2000s amps...... Here's the particulars on the amp. It operates 80 - 10 meters and I've run them on the WARC bands at reduced power output (800 watts 12/17 meter with none of the choke heating problems found in early Alphas). Power output is normally around 1200 watts PEP with a calibrated Struthers wattmeter. My best one runs 1350 watts PEP with a set of EIMAC 8122s........ This amplifier was the first production AB2 biased amplifier. In fact, AB2 biased linears were patented by National. AB2 linears closely follow voice peaks and can make a watt meter look like a modulation meter. Nearly all current commercial linears run class AB2 now that the National patent has run out..... Many hams have called the NCL-2000 "a one call linear" meaning that nearly all pile ups can be broken by an NCL-2000 on the first call. I can attest to that fact as I quickly sold my Alpha dual 8874 amp when it was outperformed by the NCL-2000..... The amplifier runs a pair of 8122 ceramic tetrodes. A bad production run of RCA 8122s nearly ended this amplifier's production in 1965. 8122s are very reliable and I have never "blown" one. I believe the amplifier was produced from 1964 until 1972 and nearly 5000 of them were built. Getting a pair of 8122's is not too much of a challenge these days. RCA, EIMAC and Burle all made these tubes and Burle still has them in production. The EIMAC's are the best and a little known military variant the RCA 4662 (but made by EIMAC) can achieve 1300 watts PEP easily. Hamfests, Ebay, Qth.com and many other ham sites frequently list 8122s for sale. They have been going for around $30 - $75 each used but good....... If you end up with one get a manual (W7FG and others) and tune it up as instructed and keep the grid current well below 25 ma. I run mine with the needle just deflecting to 10 ma. on my voice peaks...... Every NCL-2000 I have ever seen needs new electrolytic caps in the power supply. When replacing them (eight each 450 volts @ 80 mf) increace the capacity to 120 mf or better. Also don't use those cheap "itty-bitty" caps or you'll be cleaning up a lot of paper and foil debris - if you get my drift! Don't forget the bias electolytic near the front panel..... My most expensive NCL-2000 was purchased for $550 within the last six months. My least was $190 with four spare 8122s!!! A good price on a working amp is around $450 while a good price on a mint amp with new caps is $550 -$650. They are extremely well built and should last another thirty years.
 
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