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| Reviews Summary for Alpha 374 |
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write your own review of the Alpha 374.
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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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W9VY
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Rating: 4/5
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Mar 3, 2006 17:11
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Update
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Time owned: more than 12 months
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At the time I wrote my original review on the 374, the picture was indeed wrong...eHam has thoughtfully corrected it...The 374 that I owned is now at N9TGR's mega-shack and still running strong with a stuck relay being the only blemish he has encountered..Still can recommend this old timer....73 de Dan W9VY
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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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WB2CMA
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Rating: 5/5
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Sep 25, 2005 09:44
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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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OK SPORTS FANS LETS GET THIS RIGHT, THE PICTURE AT THE TOP OF THIS ALPHA 374 REVIEW IS 100 PERCENT CORRECT, IT'S THE DESCRIPTION WHICH IS WRONG, THE ALPHA 374 IS A THREE HOLER USING 3X 8874 METAL CERAMIC TUBES IN GROUNDED GRID, SINGLE 19 POUND TRANSFORMER & OIL FILLED 30 mfd/2500 VOLT CAP. PRODUCED BETWEEN 01/1974 TO 03/1978. ONE REVIEWER WROTE A REVIEW FOR AN ALPHA 374A WHICH IS AN ALL TOGETHER DIFFERENT AMP. IF YOU WANT TO KNOW FACTS AND FIGURES ABOUT ALPHA AMPS, GO TO THEIR WEB SITE THE INFO IS THERE. I OWN A ALPHA 374 SERIAL #3105. THE AMP WILL DO LEGAL LIMIT +, I ADDED SECOND MUFFIN FAN AT REAR AIR INLET TO IMPROVE ANODE DISSIPATION ON THE "3 X 8874'S". HARDWARE, COMPONETS, TANK COIL, RELAYS, ETC ARE ALL SUPER HEAVY DUTY, THEY DONT BUILD THEM LIKE THIS ANY MORE. ALPHA ONLY BUILT 384 OF THESE GEMS. MINE STILL HAS THE ORIGINAL "3 X 8874 TUBES. THE ALPHA 374 WAS AN EXPENSIVE AMP IN 1974 WELL AHEAD OF IT'S TIME, IN-RUSH PROTECTION, 80 THRU 10 METER OPERATION, NO-TUNE BANDPASS OR MANUAL TUNING,GRID AND PLATE PROTECTION CIRCUITS,
NORMAL AND EXCESSIVE GRID LED'S, SSB AND CW/TUNE
MODES 2400 OR 1600 VOLT OPERATION,BUILT IN FORWARD & REFLECTED RF METER, PEP INPUT METER, ALONG WITH STANDARD GRID PLATE & HV METERING.
ALL OF THIS PLACED INSIDE HIGHLY CRAFTED AND POLISHED ALUMINUM CABINET. TODAY THIS AMP IS RARE AND THE HAMS WHO LAYED DOWN THAT KIND OF CASH IN THE MID 70'S MOST LIKELY TOOK VERY GOOD CARE OF THEM. I HIGHLY RECOMMEND THIS AMP, IT PURR'S LIKE A LION.
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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NJ0G
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Rating: 3/5
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Sep 22, 2004 13:11
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Correction -- wrong photo and description!
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Time owned: 0 to 3 months
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The PA-374A used two 8874 tubes, not three. As "stock" its gain figure was about 10 dB. It lacked a tuned input. Accordingly, 100 watts drive = about 1,000 out. (With a tuned input the gain figure could reach 13 dB; 50 watts drive = about 1,000 out. Not an easy mod.)
The '374A was patterned after the PA-76A, a manually-tuned model introduced coincident with FCC-mandated "type acceptance" (limited gain figure to 13 dB and eliminated 24-35 MHz coverage).
The'76A / '76PA, and the PA-374A all used the same 1.5 kVA CCS rated (and true!) Berkshire power transformer. It weighs about 48 pounds. With the Berkshire the plate voltage regulation was significantly better than that of the "original" 3-tube PA-374. In my 20+ years with Alpha I never saw a Berkshire fail.
The cost of the 8874 is high. The 3CX800A7 is a better choice (only need one!) when tube replacement is necessary. The transformer filament winding provides 6.3 V @ 10 amps. This can be raised to 13.5 for the '800 with a full-wave (rectifier) doubler and regulated with a TO-3 case IC.
Add a muffin-type low-volume (for quiet!) "pusher" fan to the air intake area to aid cooling. The amp can then be passed on to your grandkids...
73, Ray NJ0G -- Colorado Springs
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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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