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write your own review of the Alpha 374.
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AK0O
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Rating: 5/5
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Dec 28, 2011 07:27
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Very Easy to operate
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Time owned: 6 to 12 months
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My Alpha 374 has three 8874's, the manual reads as though this is normal and not a mod. So I am wondering if some 374's were two tube models and some three tube models. The amp puts out from 900 to 1200 watts in bandpass mode depending on the band I am operating on. Very quiet and cool running amp. I like the bandpass mode as one does not have to do any plate or load adjustments, just turn the selector to the correct band and present less than a 1.8 swr to the amp! How easy can you get.
I received this amp from a guy who seldom used it, he got it from a guy that used it as a standby amp, the amp does look like it just came off the shelf at the store. I plan to use it till the tubes dies than do the tube upgrade. Of course if three 8874 tubes came around I would continue to use the amp as is.
If you see one used buy it!
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KR4JA
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Rating: 5/5
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Sep 6, 2011 10:39
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Excellent vintage amp
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Time owned: 0 to 3 months
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I just picked up a 374 (thanks Randall), in immaculate condition, silver front, no sticky paint. The only mods I can tell are the addition of a 3rd tube and the RCA input has been changed to an SO239. The amp runs quiet and gives me 1000-1200 out in bandpass mode on each band (legal out with manual tune).
I may eventually upgrade the amp to 2 x 3CPX800A7s (like my 76PA, which was upgraded by N4UQ), but for now the 3x8874 tubes are full output and draw <20ma grid current at 1200W (SSB) using the bandpass mode. This is a great vintage amp (built in 1976-7) which uses a large oil-filled capacitor in the HV supply, a Hypersil X-Frmr (I’m getting ~2350V on high tap), and far surpasses the quality of other no-tune amps I’ve had (which include a Hercules II, 2KL, LK450NTC, and LK500NTC).
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NN3RP
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Rating: 5/5
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Nov 8, 2010 12:09
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Excellent Performer
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Time owned: 0 to 3 months
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Over a month ago I picked up a 374 here @ Eham
3 x 8874 = 374
SN 3265
Not too many of this model were made by Alpha.
This one had been modified with special larger knobs for Tune / Load. The knobs have numbers from 0-100 while the original numbers are behind each knob on the faceplate. This will make for real fine adjustments on Tune / Load. I particularly like these larger knobs.
When I first got the amp, it came with the power cord almost roasted / cracks all along. It was dangerously bad a power cable. The light bulbs were also out. I power it up like this just to see how it will performed but I was disappointed to find out that I could not manually fine tune it following the user's manual instructions. It will work just fine in no-tune mode but the power out was not to my satisfaction. Something was not right, I thought.
The former owner refused to get it back. So I was left with the issue.
Bring Richard Byrd, N4UQ!!!!
A search on the web pointed to Dick as a person who deals with this brand of amp so I contacted him. After several phone calls and emails explaining the issue, Dick took the amp for troubleshooting.
Dick replaced the power cable and lamps. He also measured the temperature on each of the three tubes and they were all the same. Fortunately, he told me, there was nothing wrong with the manual tuning. What I was missing was the proper Tune / Load positions. He made for me a test data sheet from 80-10M so I just simply place it in that spot when changing bands and adjust a bit. Dick was surprised to see the unusual knobs himself but admitted it was a good thing to have. It cost me not much to have the work done by Dick. The satisfaction of knowing that the amp was in excellent condition was invaluable to me.
Now this amp can go close to the power limit or more??? With about 60W, it can fly very close to the limit and the green light starts to flicker. It takes about less than a minute to warm up. I keep it in SSB at all times no matter if it is CW / SSB the mode I am using on the radio....linearity!
Now its fan is noisy and I even added an extra large PC fan to aid it in cooling the tubes. It also makes a clacking noise when TX. I don't care much about the noise since I only use it for contesting mainly. One call and it breaks the pile-up!!!
It helps much to have a XYL as amateur radio operator too...hihi
My $.5
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N5UD
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Rating: 4/5
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Oct 23, 2010 08:55
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Good 3 holer but noisy
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Time owned: more than 12 months
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I bought one new circa 1975. Quality Alpha build, but blower system was noisy. I even found it to be noisy when operating with the cans on. Bandpass mode picky as to what kind of load it was operating into. The protection circuits did work hi hi. I used manual tune some times.
If I came across one used, I would want to check out on all bands. Those 374's sure are expensive. So would be any bandswitch problems.
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KC5BHJ
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Rating: 5/5
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Apr 30, 2007 09:04
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Great Amp
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Time owned: 0 to 3 months
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The 374 is a great amp, period! Just getting back into ham after a 7 year layoff. I looked and looked for a used Alpha. I found a used 374 on ebay. Paid $ 1,275.00 for it plus shipping ($ 300.00 for next day). It had dyno tape on the face plate. After removing it, I pluged her in, turned her on, set the band switch on "no tune" on 80 meters. Set my FT-100MP at 60 watts out, said hello and low and behold...1250 watts out!!
How simple can it get???
I get unsolicted excelent reports on my signal all the time.
Before, I ran a Alpha 89 and a Ten Tec Titan 425, both great amps...but this 374 is as good, if not better...
All I can say, if if you find a good one, BUY IT!!!!!!
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WB2CMA
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Rating: 5/5
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Sep 25, 2005 11:36
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BUILT LIKE A TANK, ROARS LIKE A LION
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Time owned: 0 to 3 months
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FURTHER INFO ON ALPHA 374 AMP.
ATTRACTIVE SLEEK DESK TOP DESIGN WITH FRONT FOLDING TILT STAND "BAIL" WEIGHING ONLY 52 POUNDS. ELABORATE PRESURIZED 115 CFM FORCED AIR FULL CABINET COOLING WHICH VENTS TO THE REAR, PLUMING DESIGN WHICH LOOKS LIKE SOMETHING FROM UNDERNEATH THE HOOD OF A NASCAR RACE CAR!.THIS ALLOWS YOU TO PLACE OTHER GEAR ON TOP OF AMP. SILICON STEEL (HIPERSIL) TRANSFORMER, MAXIMUM POWER INPUT 3 KILOWATTS PEP/SSB OR 1 KILOWATT AVG. KEY-DOWN CARRIER D-C INPUT, CONTINUOUS DUTY, NO TIME LIMIT. CONTINUOUS MANUAL TUNING 3.5 TO 30 MHZ. 120 OR 240 VOLT 50-60 HZ OPERATION. 1.5 KILOWATT+ PEP/SSB, 600+ WATTS CARRIER RF OUT-PUT. ELECTRONICALLY-CONTROLLED TUBE WARM-UP TIME DELAY APPROX 60 SECONDS. PLATE HV OVERCURRENT RELAY PROTECTION. ALC EXCITER CONTROL. BANDPASS NO-TUNE
FILTERS FACTORY ALIGNED FOR OPTIMUM HIGH POWER SSB OPERATION INTO 50 OHM 1.5.1 VSWR OR LESS 80 THROUGH 10 METERS. MANUAL TUNING 2.1 VSWR OR LESS.
CABINET TOP AC INTERLOCK AND HV B+ SHORTING BAR PROTECTION. SILVER PLATED RF TANK COIL AND HEAVY DUTY CERAMIC SILVER PLATED BAND SWITCH. 3KV PIV/SILICON STACK 100 AMP DIODES IN FULL-WAVE BRIDGE CIRCUIT, "NO VOLTAGE DOUBLER CIRCUIT HERE"
TRANSFORMER HAS THE JUICE. BEST RF POWER OUT-PUT TO WEIGHT RATIO OF ANY AMP EVER BUILT THEN AND
NOW. JUST THOUGHT U LIKE TO KNOW A LITTLE MORE ABOUT THE ALPHA 374.
DAVE WB2CMA
PROUD ALPHA 374 OWNER
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KG4LRU
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Rating: 4/5
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Sep 18, 2005 17:40
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ROCK SOLID
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Time owned: more than 12 months
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I pick up my 374 about a year ago it was a one owner, And it had sticky paint problem which was quickly removed and resprayed silver like the rest of the cabinet, I have had several older amps this one makes great power I find very easy to tune up the band pass tunning works well and quickly unless you want to go over a Kilowatt of power it uses 8874 Tubes mine our the original tubes and will put out 1500 watts , I wouldnt recomend it as to SOP . But its there if you should need a little edge, well built even by todays standards. The amp is a work horse and will perform on 10-80 Uses Three Tubes . Very compact in size and very clean signal. The bad points relay CLACK Clack and Clack it does make a bit more noise also it suffers from a noisy fan for cooling it uses a muffin fan that presurizes the final compartment its the reason you shouldnt push it over the rated 1300 watts . the fan system would be very difficult to re engineer on the 374 due the lack of space . Also be sure the tubes our in good order, retubing this will cost more than the amps worth , If you find a nice one that has been taken care it will get job done. Tubes our very durable and our not prone to being damaged the amp does have some very good protection features that werent found on amps be offered back in 1974 .
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WK4B
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Rating: 4/5
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Nov 4, 2000 11:35
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Oldie but Goody
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Time owned: more than 12 months
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I bought this amp from the original owner (now a silent key). Serial number 7232, It originally only had two tubes (8874). I had amp modified for warc bands and added third tube, now full power on all bands with 90 watts drive. This is a great old amp built like a Mack truck. Put new front panel on amp now it looks like it just came from factory.
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K2UA
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Rating: 3/5
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Mar 1, 2000 11:36
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Good 80-10 performer; weak in some areas
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Time owned: unknown months
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I own a very early 374, made in 1973 or so. It made good power when it was in service. Covers 80-10 meters, has a Hypersil transformer, and is in a small, desktop case. Tuning and loading adjustments were done with small knobs directly driving their respective capacitors; larger knobs would have been helpful. The bandpass tuning worked pretty well, although it was a horror to adjust if you wanted to move it to a different part of the band. Cooling was poor. A mid-chassis-mounted, high-grade muffin fan sucked air in over the PS and past the output network, where it had to make a right-angle turn through the tubes, another right-angle turn at the tube air outlets into a (roughly) 1.5-inch-square plenum, and out the back of the amplifier through a small piece of screen. The amp worked well much of the time, but developed problems (high second-harmonic content on 80, which cleared up when I replaced the toroidal 80-meter inductor in the output network). A magnificent parasitic oscillation also whacked all three tubes and blew the contacts off the selected band on two sections of the four-section bandswitch, resulting in a large parts bill and a small investment in an AG6K parasitic-suppressor kit that calmed the amplifier down completely. Later UPS dropped the amplifier during shipment and really hosed the chassis, meter and meter switch. I found that the special six-button meter selector switch and the meter movement were made of unobtainium, so the amplifier now sits in a corner of my basement, unceremoniously holding down a section of the floor. In its day this was a fine piece of gear, but today I'd pass on an original 374 in favor of almost anything with two 3CX800s or one 8877 and good cooling.
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