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Reviews Categories | Amplifiers: RF Power - HF & HF+6M | TenTec Hercules II Help

Reviews Summary for TenTec Hercules II
TenTec Hercules II Reviews: 33 Average rating: 4.9/5 MSRP: $1395.00
Description: Full QSK, 500W solid-state amplifier
Product is in production.
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KA2ZSD Rating: 5/5 May 29, 2018 23:44 Send this review to a friend
Very nice souding   Time owned: 3 to 6 months
Works great with Icom 746pro /going use next with Icom 7610
KD0ZV Rating: 5/5 Aug 26, 2017 05:59 Send this review to a friend
Has worked flawless  Time owned: more than 12 months
This is my last piece of TenTec gear and at one time that is all I owned. I have owned this close to 15 years. Has never missed a beat in the entire time and puts out a clean 550 watts on the bands I operate. I have the optional power supply which is large and heavy and sits behind the bench.

I keep getting the itch for another solid state amp to try something new but why?

One of TenTecs better offerings for sure.
G0MJK Rating: 5/5 Jul 12, 2016 03:19 Send this review to a friend
Great Solid State Amp  Time owned: 0 to 3 months
I was fortunate enough to aquire the Hercules II and the matching power supply in a deal for some Collins equipment. I am currently using it with a Yaesu FTdx500MP and reall cannot fault it at all. Into a dummy load it produces 600 watts with ease and is very quiet in operation. If you get the chance to buy one get it preferably with the matching psu but be warned this weighs in at 58 lbs and is built like the proverbial brick outhouse.
WB4TJH Rating: 5/5 Sep 30, 2012 16:18 Send this review to a friend
Run it conservatively and it will last forever.  Time owned: 3 to 6 months
I bought my Hercules II several months ago, from a friend, its original owner. I power the amp with the largest marine duty battery that Walmart carries, and it does just fine. I usually run no more than 400 or so watts, and the Hercules never whimpers. The amp is rated for 550 watts continuous, but I prefer to run it more conservatively, since the final transistors are harder to come by now and expensive. I just wish Ten Tec would reintroduce an updated model of this amp and if they design it as well as my Hercules II, it will also be a winner and see many, many years of trouble free use. I have owned a a lot of Ten Tec gear over the past 40+ years, and have always gotten splendid service from the gear and the service staff at Ten Tec. The icing on the cake is, Ten Tec is a successful AMERICAN company, and its a pleasure to deal with them. This amp is a winner, and if you get a chance to buy one in as good a shape as mine, jump on it. It's the "good stuff".
W5XJ Rating: 5/5 Aug 16, 2012 10:26 Send this review to a friend
An easy 500 Watt Transceiver  Time owned: 6 to 12 months
I agree with the previous poster. Set the drive ot match the power you need for your QSO. I run mine in QSK mode at the direction of TT even though I don't do any CW. I run mine off a large 190 AH deep cycle battery for now until I get the dedicated circuit I need in the shack for the 9420 that I also have. This thing is amazing and works like a champ. It even does 60 meters (at 100 watts max, of course) and the WARC bands too. Maybe Ten-Tec will bring it back one day. Paul says the PA's are too expensive and nobody would pay what it would cost? The PA's used in the amp are no longer made so if one blows the whole thing is toast. If you find one of these in FB condition at an estate you should buy it. 73 & good DX!
KU7I Rating: 5/5 Jun 27, 2011 06:18 Send this review to a friend
very good 500watt class amp  Time owned: 3 to 6 months
Bought this used from the 2nd owner. Had to adjust R3 on the control board so I could get 550 watts out on all bands before it would go into "overdrive". See some of the reviews here for mods to make improvements. Also Google "ten tec hercules" and you will see some other websites for improvements. I use two Astron RS-70's and it works perfect, 550 watts out all day long in ssb or cw. I have not tried the full qsk mode since I only use semi-qsk. The "standby" mode is putting the amp in qsk from the front panel if using the relay key method. Took me a while to figure this out. I usually need about 40 watts of drive for 550 watts out. Collector current is way under max with 550 watts out. I customized the power plug so one RS-70 feeds amp modules 1 and 2 and the other RS-70 feeds modules 3 and 4. I do NOT use the Astron "parallel" jack on the back of the supplies. You could run (4) RS-35s by running one to each of the 4 amp modules. This is how Ten Tec does it with their power supply designed for the amp. They use five separate 20 amp PS, one for the driver and one each to the four amp modules. Took me a while to figure out how they did it. I really really like this amp. VERY user serviceable. My only gripe is the case is cheaply done and the molex connector is not the best way to go for high current. I have not replaced the stock molex connector but plan to do so later on. This is a lifetime keeper. Ten Tec made a fair amount of these so they are not too hard to find on the used market. For serious dx or serious rag chews on 40 meters I use another tube type amp that gets me legal limit output but for most other qso activity I run the Ten Tec. Also this is my first solid state amp. I run all bands 160 to 10 including WARC so this was a good choice. I was also looking at the Icom 2KL but liked how easy this was to service. Also liked how you have options for the B+ power source. Can not recommend enough. The manual is available for download on the Ten Tec site. The matching PS is available for download on another site somewhere (Google Ten Tec 9920 and you will find it). Ten Tec does not yet have it on their website as of a few weeks ago. Get one and have fun, just keep in mind this is a 500watt OUTPUT class amp. Each of the four modules is rated at 250 watts INPUT which is only 1000 watts input max so 550 out is a reasonable expectation. Watch your collector current. Each module is rated at 18 amps max which is only 72 amps total. 550 watts out is way below this max (somewhere around 60 amps). I love this amp. I wish they would make a 1kw output version. You can email me at if you have any questions. I have heard the transistors used in this are no longer avl. I have not verifed this but I also expect that they should last a lifetime if the amp is run according to specs. I also run the two RS-70s at 14.4 vdc each. with two in parallel I see around 40 amps of current draw per PS at max power out keydown.
W4VKU Rating: 5/5 Mar 29, 2011 00:49 Send this review to a friend
A good amp. Works real well  Time owned: 0 to 3 months
I had an ALS-500M. Did the QSK mod and did not
like the crankiness of its SWR foldback scheme.
I was looking for a light weight amp to carry to
VU4PB. In my long search for value/weight, i
did consider the ALS600 and the Tentec Herc II.
After reading some reviews, i decided to try the
Tentec Herc. To my good luck, i had a local ham
offer one for sale. I purchased the amp.

Performance - I ran the Amp on SSB and RTTY on
17m from VU4PB. I used a 2ele+40m steppir. The
30m swr was a little bit below 2:1. The amp did
not wink. I used it during my entire stay in
VU4PB and like the amp and recommend it to anyone
needing a value amp. I used an Iota Engg 90amp
supply. This amp might actually draw more current
like others had pointed out. I could not find a
PS that would do more than 90amp @14.4v and is
lightweight/rugged/reliable. Did over 2000 Qso's
with it and got good reports from many parts of
I sold the ALS-500m which is ok for casual op, but for a Dxped, i think the Tentec Herc is a
winner. It lived to its reputation for a good,
reliable amp. Never over drove it.
If you find a clean one, pick it up.
ZS4U Rating: 5/5 Nov 3, 2010 02:15 Send this review to a friend
Amazing little Amp!  Time owned: more than 12 months
Had mine for a year now after picking it up second hand for $550. What a good "investment"! I agree with all the 5 ratings earlier - such a shame that Ten Tec stopped producing such bang for the buck........ Anyway - used it in a contest for the first time - ran the whole weekend at 400 watts with NO glitch or fans screaming to pump out heat! Did 1200 QSO's in about 20 hours on 10M. If you can lay your hands on an untampered one - GRAB it!
W4CSC Rating: 5/5 Jul 20, 2009 21:30 Send this review to a friend
honest 650w after cleanup  Time owned: more than 12 months
Read the reviews of my fav mobile amp I've had for years. Once you get the "cheap" out of it, like feeding 100A through a cheap Molex connector, and getting rid of the 5A pushon connectors inside it's a great amp. Remove all the pushon DC wires and replace with fine stranded high power car stereo cables. Two 60A fuses in rear air plenum in holders. #0 cables from here to battery. Same from fuse block to central power distribution board. SOLDER to tabs cheap 5A pushons came off of and solder heavily all DC traces/tabs on this board. Solder #4 from this board to each of the 4 amp boards, heavily. Amp draws 120A after improvements now running on 13VDC, not 10VDC from Molex and pushon wires. DO NOT CONNECT TO SCREWDRIVER MOBILE ANTENNAS as they will be destroyed. Homebrew bug catcher has big coronas at top on 40M down....(c;]
73 DE W4CSC/M4
KQ0C Rating: 5/5 Oct 17, 2007 13:21 Send this review to a friend
Doesn't get any easier  Time owned: 0 to 3 months
I bought a used Herc II on ebay in terrific condition. This is my first amp... and what could be easier? No tuning... and a dependable 500 watts. When I forget to switch bands, no output, but no other dramas. I'm using a Astron 70 AMP power supply, which handles 500 watts just fine. The total package (amp and power supply) cost me $1,000 which is barely more than a new tube amp would run... and I can QSY at will instead of spending all my time tuning.
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