| VA2AM |
Rating:      |
2022-10-08 | |
| High quality over rated HV RF sections |
Time Owned: 0 to 3 months. |
This is my first Acom product, I was looking for an amplifier that will easily work at +1.5 kw no time limit. First this 4Cx1000A tube looks to be limited but these new ones are POT tested at 6 Kv and not an issue at 3.5Kv. Well I got an issue after just 3 hours, it got dead,,, excellent Acom technical support, they emailed me the complete service diagram with picture where to take some voltage on the main pcb. Defective +5 volts supply down to 1.3 volts. I replaced LM7805 side panel and back to working conditions. Everyday use quick QSY, running a net the fan stays at low speed all the time.
Yes, you must take your time to install their heavy transformer and connecting all the wiring after selecting your AC voltage output. Very low dual fans noise, all parts are exceeding the required level mainly in the HV and Rf section, large vacuum relays using some flat wires, double cover for the RF section. No sweat to get full power with 2:5 swr, it is still in specs. I really like their auto 6 db attenuation during the tuning with the fast TRI indicator. You do not have to reduce your RF power. 13.5 db tetrode gain needs more RF power compared to a 3CX1500A7 triode, but we are talking here about +15-20 watts more to get 1.5 Kw with a better linearity in AB2 class. This tube will run a at lower temperature. Still a good margin at 1.5 kw left before reaching the maximum output. You cannot miss a perfect tube resistance TRI tuning. Over 10x safety parameters to protect this tube and they are saved on a non-volatile memory. At +65 lbs / 29.5 kg we are in the top-class single tube amplifier.
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| W7PV |
Rating:     |
2021-12-08 | |
| Excellent amp; glad I bought it. |
Time Owned: 6 to 12 months. |
Having used an SB-220 for decades, I decided to upgrade to the ACOM and am very happy I did.
However, some comments are appropriate:
The Good:
- The tuning and metering are excellent. The TRI (True Resistance Indicator) tuning allows the proper load resistance to the final and maximizes tube life.
- The RF forward and reflected power readings are very precise.
- The amp loafs along at 1500 W output. Once tuned, it is easy to return to the same settings for a given frequency and antenna.
- It appears to be very solidly built.
- The manual is detailed and very helpful, especially for tuning the amp properly.
The Other:
- Having to install the power transformer which came separately boxed was a bit tedious but not difficult. Apparently the total weight of the assembled rig may result in damage if not handled very carefully.
- Waiting 3 minutes for warm up takes getting used to, especially when that DX is available right now and may not be later. I enjoyed the instant on of the SB-220.
- The need to allow vertical space for the exhaust fan is problematic for me as I have cupboards above most of my operating space.
- The amp totally quit after about 4 months of light use; turns out the AC cabinet interlock switch became resistant and fried as the rig was warming up, and there was nothing visible inside the cabinet that would provide a clue as to the problem. Fortunately the tech I talked to had seen this in other ACOMs and alerted me to it. After bypassing the switch and finding that was the problem, he sent me a replacement. It appeared to be a 50 cent Chinese made switch, not quite the quality I had expected. The thought of having to remove the power transformer and box up the radio for a repair shipment was not something I wanted to do, and fortunately was able to avoid that.
- The ceramic tetrode is very pricey; hopefully that will last longer than I will.
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| WJ3Z |
Rating:      |
2020-08-31 | |
| A real workhorse! |
Time Owned: 3 to 6 months. |
| I purchased my 2100 from HRO in March of 2020. With COVID happening it slowed things way down and after talking with HRO they also stated that ACOM is very slow. Well that was true, I almost canceled my order, but after 4 months of waiting I finally got it delivered in June and I absolutely love it! I run it with my ICOM 7300 and it is a wonderful amp. It is very quiet and extremely easy to tune. 50-55W will get 1300+ out of the amp and it just a beast loafing along at that level. I havent had a chance to tru it on 6mtrs yet but I am sure it will be fine. |
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| K1HL |
Rating:     |
2020-05-09 | |
| two glitches |
Time Owned: 3 to 6 months. |
The 2100 is beyond superb; but, in my case two little glitches. The 3,500V B+ got the better of this amplifier - exactly two times, and according to the I-Com tech it's lucky I didn't lose my IC-7300.
After about four months of owning the 2100, the B+ arced to ground. (firecracker!). Ten minutes later, did it again. For the first four months this had never happened, and it hasn't since. I'm crossing my fingers.
As for the amp; after having built and then used the same SB-200 for 48 years, I could not believe how easy it is to tune the 2100 - 10 seconds. I would strongly recommend this toy - if you've got the bucks. |
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| N9CHM |
Rating:      |
2020-03-07 | |
| EXCELLENT AMP! |
Time Owned: 0 to 3 months. |
| I added an ACOM 1000 to my station for 160M-6M coverage in 2018 since my 374A Alpha did not have 6M. Found a deal on an ACOM 1500, so upgraded to that, and then to the ACOM 2100 when the opportunity came up. All 3 ACOMs are very well made and worked great! The build quality is excellent, probably since they are made in the same facility which made the Alpha 91B. Another key advantage is their ease of tuning with the TRI tuning system. The 2100 is a beast, with the same tube as the ACOM 1500 (4CX1000A), but with a bigger Xformer running ~700 more volts on the tube (ACOM 1500=2880V and 2100=3580V), it is capable of 2400W, will do 1500W on RTTY and digital modes with no time limit (with an optional external fan) and 2000W for SSB. It just loafs along at 1500W on SSB, which is what I wanted. I did disconnect the power leads to the external muffin fan since I only run SSB and the external fan is only needed for 1500W no time limit for digital modes. JUST TO NOTE: After a week of nightly rag-chewing at 1500W, with only the internal fan running, the amp never got above 52C (125F) on long SSB transmissions, and quickly cools down to under 40C (104F). This is well below the tube specs of a maximum operating temp of 200C. The internal fan alone, does an excellent job of keeping the tube cool in SSB mode, as the manual said. I guess fan noise is pretty subjective, but the 2100 is pretty quiet with just the internal squirrel cage fan (but not as quiet as my 374A or Drake L7, both of which had the least fan noise of the amps I've owned-and I've owned many over the last 40yrs). One of the reasons I moved back to ACOM after using a Palstar LA-1K solid state amp (which is a super amp, by the way), is that I don't need to worry about small SWR changes due to weather. Really need to keep the SWR as close to 1:1 as possible with most solid state amps, and the Palstar is no different. The ACOM will happily play into a 3:1 SWR, another advantage of the ACOM over other amps. NOTE OF CAUTION: After you install the transformer, check the 3 pin connector located on the edge of the board which swings out so you can set the Xformer in place (see pics on my QRZ page). I either accidentally loosened the connector, or it was loosened in shipment, once re-connected the amp fired right up! The amp runs cool and quiet at 1500W SSB, and the tuning is really slick and very easy. Very happy with all 3 of the ACOM amps, and especially the 2100. |
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| NS3L |
Rating:      |
2020-02-11 | |
| ACOM 2100 ... Solid as a rock, & Performs like a champ.. |
Time Owned: 3 to 6 months. |
In October 2019 I purchased my very first legal limit amplifier from DX Engineering. I'm a long time ACOM user for 7+ years, I knew the reputation of ACOM as a company right from the start for making rock solid easy to use amps. My first amplifier was a Solid State 600W ACOM 600S I purchased from Array Solutions which continues to give me years of great service. However, being a contester running a two position station, I wanted to have a pair of versatile amps providing both mid (500W-600W) and high power legal limit (up to 1,500W) output for times if ever needed.
The ACOM 2100 is solid as a rock and performs exceptionally well in all conditions. The ACOM 2100 consistently, and repeatably is able to achieve whatever wattage level I call for, and is, by far simply the easiest amp to tune in just a matter of a few seconds. In my case since I purchased it from DX Engineering, I had them provide and install the 220V power cable connector. It's worth it and saves the hassle. Just plug it in after assembling the two major parts and turn it on.
The ACOM 2100 is shipped in two boxes. It's very easy to assemble the two major parts of the amp. All you have to do is follow the very detailed assembly instructions which are easy to follow. Power it up, wait for the timed warm up to complete, and tuning is as easy as you can get with ACOM's built in tuning aid.
Amp protection is what stands out the most with ACOM amplifiers. This amp will protect itself in a split second if you manage to have something wrong, or it detects some other problem.
You can't go wrong with ACOM amps. I'm a proud owner of two of ACOMs finest amplifiers..!! You can't get anything better. Steve & Sharon NS3L & N3SET |
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| N7ABL |
Rating:      |
2019-06-02 | |
| A Real Thumper |
Time Owned: 6 to 12 months. |
I join the previous reviewers with my praise for this rugged amp but there were some speed bumps:
1.) The transformer is so heavy that it requires separate packaging, bolted to a thick piece of scrap plywood. Before installing, one must ignore the instructions that state that the dealer installed the miniature jumpers that set the low current necessary to operate the tube's filament. I did not check the jumpers settings and could not get the amp to work. The dealer did not set the jumpers. Several telephone calls to the dealer gained me a new amp in exchange after which I reset the jumpers to their correct positions. Power flowed after my bad was corrected. One must also set the HV pins but these are larger, easier to see and clearly marked. I had a 240 VAC fixture installed in my radio room. The dealer wired the amp's plug. It all worked.
2.) On the air, this amp is splendid. The amp is more of a semi-automatic given its ease of tuning, described in its entirety on various websites. The amp will tolerate up to 3:1 SWR's without a tuner. Ease of tuning is a great feature as so many don't know how to tune an amp properly. The 4CX-1000A/8168 ceramic tetrode, originally designed and manufactured by Eimac, has a practical output of 1,630W per the manufacturer's data sheet as a clear PDF on line. Today's tube is a Chinese copy, made well. Replacements are available from RF Parts Co. who offers tubes of various prices based on condition (e.g., clean medical pullouts, more recent NOS, etc.)Absent over driving, the tubes have relatively long life. Apparently, some overdrive it, however. For good linearity I suppose some tune the amp at around 2,000W and then reduce the drive to generate but 1,500W or less so as to gain better linearity by reducing the drive, an acceptable practice provided one is using a dummy load but "everything to the right" makes little sense if one considers the minimal increase in dB at the risk of frying the rig. This amp doesn't need to be pushed.
3.) The amplifier employs a muffin fan on the intake, located on the back right side of the chassis. A robust squirrel fan pumps air throughout the RF deck and exits out a vertical stack on the left rear of the cabinet. The result is enough heat to roast an ox. Cozy in winter, it is not so fun in the summer. Fortunately, my radio room is cooled by a good air conditioner but the heat can be oppressive if one is not attentive to it. Fortunately, the exhaust temperature is measured and displayed upon the operator's need by the built in OLED meter information display. Despite the heat, the fan noise is minimal.
Acom is based in Bulgaria, a former Soviet bloc satellite country in part known for manufacturing high quality electronic communications equipment. While the old Svetlana amplifier tubes, mostly made in St. Petersburg, said to be copied from Eimac, are no longer readily available, adequate and probably those of better quality are on the market, made in China. How the evolving trade war and tariffs may affect availability is anyone's guess. I still rate this amp a five because it is robust, of good design, well constructed, enjoys good dealer and manufacturer's support, has an outstandingly simple tuning procedure and the problems noted were my fault but for the heat. Those who buy tube amplifiers know they are going to be hot; just a matter of how much. So, if you want a really well engineered and performing, powerful amplifier perhaps you will join me in the ranks of ownership of this fine product. Cheers de N7ABL, QRO but SK for now. |
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| G8DX |
Rating:      |
2019-03-02 | |
| The best amplifier I've ever owned |
Time Owned: more than 12 months. |
Quiet, smooth, powerful, stylish and high quality.
Little else to say about this amplifier - I've owned and operated most tube amplifiers on the market from a Yaesu FLDX-2500 to an OM-4001A. This is the best overall package if you don't need automatic band-changing/tuning. |
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| KB8O |
Rating:      |
2019-01-22 | |
| The best amplifier yet. |
Time Owned: 0 to 3 months. |
| I have had many amps in the past from tube to solid state. The Acom 2100 by far is the quietest amplifier both in general fan noise and keying I have had. I find myself looking at the watt meter to make sure I took the amp off of standby. Easily does legal limit on all modes. Couldn't be happier with this amplifier. |
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| N2DY |
Rating:      |
2019-01-19 | |
| Effortless Power |
Time Owned: 3 to 6 months. |
| This amp can run at legal limit all day long. It is easily capable of 2,400 watts into a dummy load. Tuning is easy as can be. Internally it looks a lot like the excellent build quality of my Alpha 91B. As others have noted, these guys built the 91B for Alpha years ago. I guess they took that experience and applied it to their own designs. It has all sorts of protections for the amp for when you make mistakes, as I inevitably will. If you want a reliable, really well-made legal limit amplifier, stop looking. The 2100 is it. |
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