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Reviews Categories | Amplifiers: RF Power - 6M/VHF/UHF+ | Alpha 8406 Help

Reviews Summary for Alpha 8406
Alpha 8406 Reviews: 9 Average rating: 4.7/5 MSRP: $4250
Description: Full Legal Limit, Manual Tune, No Time Limit Amplifier. The Alpha 8406 is a 6 Meter, 50 - 54 MHz, 1500 watt Linear Amplifier that is capable of key down - no time limit performance. It uses a single 4CX1500B tetrode.
Product is in production.
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NZ5F Rating: 5/5 Jan 29, 2019 10:01 Send this review to a friend
Nice amp for 6m  Time owned: 6 to 12 months
I have been looking for a good amp for 6m that i could use for Meteor Scatter and EME. I was able to get this lightly used older model 8406 and got it for a great price. With 40W in I get close to legal limit. I don't push the amp too much because this is currently my only 6m amp and i need it to be there for me. A couple gripes. This older model will pop the 2 amp fuse if you leave it plugged in. This is a known issue and Alpha technical rep told me that I should unplug it after use. Secondly, my amp doesn't have a certain mod that makes it occasionally required that you need to cycle the power button for it to energize. Other than that it is smooth operation and legal limit output from this amp. I plan to get a new tube for it in the next year or so as a backup in case they go up in price. I really like this amplifier. It is a real beauty.
K0GUV Rating: 3/5 Oct 6, 2014 07:32 Send this review to a friend
Jury is Out  Time owned: 3 to 6 months
I have had Johnson 6&2s in the past with no problems except they could not reach the legal limit I guess I should have been content with that but I wasn't Had to have more power Bought the Commander 2000 plus was a great amp but became an orphan when Pat had to hang it up.. Bought an Alpha worked Great for about 6 months dropped to 1000 kw had a bad tube am in the process of replacing it with a new one the company provided.My complaint is that I don't have a PHD in computer science and that's the only way I can install the tube... I hate computers. It is probably going to wash out as Alpha has been great in support. Whats wrong with a plain old every day 1500 watt amp ?????
KC0W Rating: 4/5 Apr 7, 2013 09:21 Send this review to a friend
So Far So Good  Time owned: more than 12 months
No issues or problems with the amp after roughly 1.5 years of usage. Radio used is a K3.

There are two (perhaps three?) fan speeds which automatically ramp up or down according to internal cooling needs. The lowest fan speed is hardly noticeable. Things really start rock 'n rolling when the 2nd (3rd?) fan speeds kick in.

Tune & Load control's are ALMOST set & forget. I have yet to find their "sweet spots". No, I'm not a newbie at this either, hihi. The Tune control has little noticeable difference between the settings of 13 - 22. The Load control has little noticeable difference between 3 - 18.

Unfortunately the amp can go several months between use. This is due to the quirky nature of 6 meters. When the band is open you're on top of the world........When it's closed I'm looking at an expensive paperweight. We have occasional Magic Band openings here in North Dakota but this amp would really shine for those living in the Caribbean, FL or other places where 6 meters opens frequently.

The amp has been used primarily on CW. I haven't experimented with any of the Digi Modes using the 8406 yet. Perhaps someday.


N9LB Rating: 5/5 Jul 24, 2012 10:51 Send this review to a friend
Lots of Super Clean Power  Time owned: 0 to 3 months
I’ve run barefoot and tried a lot of VHF amplifiers over the years, including a Gonset, various solid state “Brick” amplifiers, classic Henry 2000 series amps, and some truly awful “HF conversions”.

Barefoot operation produced good local coverage and I could also work some DX, though frequently requiring a lot of time & effort and several repeats before the contact was complete.

Then I tried running various amps to obtain a few more dB of signal. Each amp helped, but none got me where I wanted to be. Worst of all, most of the amplifiers chewed up the FM and TV broadcast bands in my neighborhood.

Especially challenging was overcoming the high propagation losses associated with multi-hop e-skip. The good news is that e-skip is pretty common so don’t worry about waiting for years for F-skip to come along. You just need high power for multi-hop e-skip!

I made the decision to get serious about 6M contesting and 6M DX-ing so I purchased the Alpha 8406.

What is different about the new Alpha 8406 six meter amplifier?

1. Superior front panel metering – no other amp even comes close.
2. Computer monitoring of all parameters via USB ( use hyperterm or AE9K’s monitor software ).
3. Effective protective circuits for the tube and every other component.
4. Very clean on air signal - no distortion and no splatter.
5. Has an effective harmonic filter! ( unlike any other amp I have ever used ).
6. Full-wave HV rectifier ( not a half-wave voltage doubler ) resulting in stability and top performance.
7. Toroidal Power XFMR – same as is used in medical grade equipment.
8. It looks and works terrific!

Wow- what a huge improvement having serious power makes in VHF operating.
- Now, if I can hear them, then I can work them.
- When propagation to a rare grid opens up, I'm now competitive in the pile-ups so I can make the contact before the band shuts down.
- During contesting, I can now "hold a frequency / run a frequency" greatly improving my Q-rate.
- No more TVI calls from the XYL or neighbors.
- Of course hearing "N9LB - nice signal you are 5-9 plus" comments always feels good.

You just can’t go wrong with an Alpha!


Lloyd - N9LB
N2TU Rating: 5/5 Nov 19, 2011 09:42 Send this review to a friend
No Brainer!  Time owned: 6 to 12 months
Like the previous reviewer, I had an early issue of this amp and RF Concepts requested I send it back for upgrades. I was perfectly happy with its performance and they had to tear it away from my shack! It ran a full 1.5KW output, quiet and a real gem. I used it during the 2011 Es season and it never burped!

But Alpha knows best!

They weren't 100% happy with their product and as usual, they stand behind their product. Molly and Gordon are the best in the business. And they are centrally located in the US!

It was returned about 3 weeks later, new front panel, new blower and an upgraded power supply. This amp is a beast... full 1.5KW all the way...50 thru 54 mhz with 30 watts drive. It eats 220 volts and spits out an easy 1.5KW. Like all Alpha amps, it has a small desktop footprint and the fit and finish is impeccable.

In short if you are serious about 6 meters and want an amp designed with 6 meters in mind and not added to a HF amp as an after thought, go with an Alpha. Current production models have all the upgrades.

It is a 'no brain' decision!
K4OM Rating: 5/5 Nov 19, 2011 09:33 Send this review to a friend
Legal limit without complaints  Time owned: 3 to 6 months
1500 watts out without hesitation, just like my 9500.
Last amps I will ever need.
K9ZM Rating: 5/5 Nov 19, 2011 06:52 Send this review to a friend
Review Update  Time owned: more than 12 months
Serial #020

Time for an update. My amp was a fairly early production unit. RF Concepts contacted the owners of the early models that they wanted to do some changes at no charge. Call it a recall. They felt that they could have done a better job on a few items. Understand, I was pleased as I could be with the amp from day one. But when it was convenient, I sent it back for the updates.

It came back with a new front panel. A new main blower unit and the tube mounting was changed a bit to accommodate the new blower. Some changes to the efficiency. Perhaps other changes I am unaware of.

I noticed that the Load control seems to be more broad in tuning than before. 35 watts of drive gets maximum output now. That's a big change from the 55-60w necessary previously. Since I operate around 50125 +/- a 100kHz it's never necessary to retune.

The blower system uses a three step fan speed based on temperature. This was new to me. Previously my blower ran on high speed. I was unaware of the lower speeds. So the amp was cool as a cucumber. When I got it back the blower could not be heard except for a whine that I found to be irritating. That just my hearing I expect. The tube also ran very warm and just a few seconds of speech or CW would kick it up to medium speed where it still ran warm. The whine changed, but was still there. The blower on the tube is a very robust looking unit. Shock mounted to reduce noise. So I contacted Alpha to ask about how to change the speed settings as I wanted the amp to run cooler if possible. And to see if I could get rid of the whine. Molly got back to me with the information and I tried all three settings. For me, I am pleased with the fan setting on high at all times. The whine that I could hear is gone, I can hear some air noise from the amp but it's minimal. The tube runs very cool with this setting. The rig volume easily covers up most of the blower noise. I am very pleased with that. I wish my HF amp was that quiet.

Even at this setting, less air is moving though the amp than before. I think that may be because the muffin fan on the back is running at a lower speed than before. That is just fine as the muffin fan blows air into the transformer side of the amp and air can be felt coming though the led display at a lower speed than before. No sense running more air than necessary in that chamber.

Tune up in the conventional manner is straight forward. But there is a new Efficiency display on the front panel. I tried making sense of how this was of some use for me. But honestly, I failed to understand. You may find this to be a useful tool.

For me, this was a superb purchase. Easy maximum output in a nice looking desktop package.
W5DNT Rating: 5/5 Oct 9, 2011 11:44 Send this review to a friend
Great 6M Legal Limit Amp!  Time owned: 6 to 12 months
Report on 8406 - Serial # 001....

If you are looking for a great high quality legal limit 6M amp, this is the one! With 37 watts of drive, the amp makes 1500w, with 800 ma Ip. The efficiency indicator really helps tweak the tuning to minimize heat output. Blower runs quietly and efficiently. The amp has several levels of fault protection. Alpha did a great job of approaching the plate voltage design, which allows the tube to operate at legal limit, well within the current specs for the 4CX1500.

In short, the folks at Alpha have hit another home run with the 8406 amp. If you are looking for a high quality, serious 6 meter amp, I do not think you will be disappointed with the 8406. Like other Alpha products, the workmanship and design is superb, as is the customer support, second to none!
K5AND Rating: 5/5 Oct 20, 2010 13:06 Send this review to a friend
Very nice product  Time owned: 0 to 3 months
I received SN003 on 10/19/10. Packaging was excellent. It took me 10 minutes to install the power transformer with the clearly written instructions in the manual. The tuning chart was very helpful, and when tuned, the unit was right in the ballpark listed in the chart. 40 watts of drive provided full legal output, and the plate and tune controls were very smooth. There are many operational safe-guards built into the amp to help minimize 'cockpit errors'. I'm now looking forward to some scatter, EME, E and yes, even F openings.

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