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Author Topic: Acom A600 Solid State 6-160 600W  (Read 85117 times)
KD8MJR
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Posts: 5557




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« Reply #15 on: June 16, 2014, 11:13:16 AM »

Right about now I expect to see those who said the IMD numbers were crap before actually seeing them to start lifting their foot up to insert it in to their mouth. Grin

As was stated by WX7G which was what I also saw.

The brochure lists the SPECIFICATIONS. "Intermodulations distortions (IMD3): better than 28dB (30dB typically) below the rated PEP output."

http://www.arraysolutions.com/Downloads/Acom/600S/ACOM%20600S%20leaflet%20small.pdf


I don't think they are terrible numbers but they are not great and certainly a far cry from the 43db that the "ONE poster" LZ1VB seemed to pull out of thin air. I am also very concerned when it says "below the rated PEP output".  We know it's going to get worst as that power goes up.

Hmm go by LZ1VB post or what the manufacturer stated, that's a tough choice  Wink

Overall it's still a very nice amp, just so long as it is reliable and thats going to be the key thing to watch and see.  BTW I certainly like the overhead they built into it, they used 1200W of finals in a 600W amp. 
« Last Edit: June 16, 2014, 11:24:31 AM by KD8MJR » Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
W5OV
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« Reply #16 on: June 16, 2014, 11:24:02 AM »

LZ1VB is Val from Acom.

So, what he says is Acom saying it.

73,

Bob W5OV
Array Solutions
North America Acom Dealer and Warranty Repair
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KD8MJR
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« Reply #17 on: June 16, 2014, 11:32:15 AM »

LZ1VB is Val from Acom.

So, what he says is Acom saying it.

73,

Bob W5OV
Array Solutions
North America Acom Dealer and Warranty Repair


It would have been nice if he identified himself so we knew who the data was really coming from.   Also I find it odd that they just used the absolute worst number to use in the manual and brochure, I would have personally printed the whole list.  It certainly paints a much better picture than their brochure.  Now the question is what is the IMD at full PEP output.
As I said before the IMD is not the number one issue for me, it's going to be reliability.
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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
W5OV
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« Reply #18 on: June 16, 2014, 11:45:11 AM »

You have to remember a couple of things here:
1) This is a brand new product
2) It is not in full production yet
3) It just passed FCC Certification

#3 means that since the FCC has approved it, Acom is planning their first real production run that should happen in July if all goes well.  All of the currently published specs are preliminary and the criticism of them is out of balance with the reality.  Not being critical of Elecraft at all ( I love my K3) I went to their website and cannot find the IMD spec on the KPA500.  Maybe I'm overlooking it, but it's not on the PDF file nor in the user manual.

Oh, and we just alerted Val to this thread and his post is his first ever on eHam.  Val LZ1VB is well-known on the Yahoo Acom group and was here in person with us a couple of years ago in Dayton.
« Last Edit: June 16, 2014, 11:48:21 AM by W5OV » Logged
KD8MJR
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« Reply #19 on: June 16, 2014, 12:16:44 PM »

Thanks for that info, I thought these where ready to be shipped, I had no idea they are still in the process of gearing up for a production run.  I guess number three explains why they used the worst case numbers.  I saw Zenki's comments on it and looked at the brochure and was also not impressed.  After seeing Vals numbers I feel much better about the IMD.
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DL8OV
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« Reply #20 on: June 16, 2014, 01:08:01 PM »

Not at all. Actually the following IMD had been measured at 600W:
1.9MHz   - 40dB
3.75MHz - 39dB
7.15MHz - 38dB
10.1MHz - 41dB
14.2MHz - 43dB
18.1MHz - 34dB
21.2MHz - 40dB
24.9MHz - 32dB
28.0MHz - 33dB
50.0MHz - 30dB
52.0MHz - 30dB
54.0MHz - 28dB

Some of those figures are good and the figure for 20m is very good. I wonder what happens after the 15m band that causes the increase in IMD? Maybe the transformer ferrites?

Peter DL8OV
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K6AER
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« Reply #21 on: June 16, 2014, 08:58:53 PM »

The lower IMD numbers are result of the combiner magnetics not being as efficient at higher frequencies. As I have said before, the FCC doesn't give a damn about IMD. Only harmonics.

We are the only communication group that wants to communicate 2.5 KHz away from a 2.5 KHz 3 dB bandwidth signal.
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LZ1VB
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Posts: 26




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« Reply #22 on: June 17, 2014, 12:37:04 AM »

Are those numbers referenced to PEP or one tone of a 2 tone signal?

Peter,
The numbers are referenced to PEP. ACOM600S had been measured in the same way as the other ACOM amplifiers. The plots are available on request.
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G3RZP
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« Reply #23 on: June 17, 2014, 05:45:15 AM »

Vlad,

Thanks.....I won't be buying one, as I bought  an Acom 1500 earlier on this year. Very nice amplifier...
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KD8MJR
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Posts: 5557




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« Reply #24 on: June 18, 2014, 11:02:38 AM »

If someone needed a great SS amp right now, there is a mint looking THP 1.2kfx going for $1200 on eBay.  I own one so I can tell you it's built like a tank and will do 850W if hooked up to 220v
It's also got 1200w worth of finals in it like the Acom.
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KI6LZ
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« Reply #25 on: June 18, 2014, 11:29:02 AM »

Only 850W? pair of indestructible 4-400s. Since 1968 keep going like the bunny rabbit, > 1200W.
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KD8MJR
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« Reply #26 on: June 18, 2014, 03:44:22 PM »

Only 850W? pair of indestructible 4-400s. Since 1968 keep going like the bunny rabbit, > 1200W.


This is an amp that is sold as 750W and yet I have seen mine hit 1kw if I am not carefull.
It will do 850W all day with no problems.
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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
AF6SA
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« Reply #27 on: June 19, 2014, 10:54:40 AM »

My only minor nitpick is the weight.  Not having read the manual I assume it has a linear power supply.  SPE's new 1.3kw amp. is a full 10lbs lighter than the Acom 600. 

There is not a linear but a switching mode PS inside.

Reading the manual reveals that there is a Switching mode PSU with active PFC inside. 
Note that PFC is required in EU.
I think PA will operate from 100VAC up to 240VAC with 15A fuse installed.
Some active PFC can even operate on 150VDC to 300VDC.
Having a stable FET drain voltage improves IMD and PA efficiency.

73's de Stefan/AF6SA



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73's de Stefan/AF6SA
www.af6sa.com
KD8MJR
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Posts: 5557




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« Reply #28 on: June 19, 2014, 11:11:42 AM »

Yeah everyone using switchers to save on cost and weight. I will take a linear supply any day of the week over a switch mode supply. 
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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
G3RZP
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« Reply #29 on: June 19, 2014, 11:35:30 AM »

Trouble with a linear supply with varying load is the PF correction required to meet the requirements of the EU EMC Directive.

But I prefer a linear PSU...
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