Issue #32: VK-AMPS Expands the Ultra High-Power Linear Amp Market

In this issue of "Trials and Errors," your columnist reviews a new linear amplifier from Australian manufacturer VK-AMPS. It's a solid performer and really well-made product. Read about it in this issue and post your questions here. We may be able to get Onder Arda the CEO to respond to your questions. 73, Dave W7DGJ

 

Excellent products.

 

Did you forget the link to the article?

73

 

It's really not necessary in that position, as that forum is linked at the bottom of the article. But I will put it there as well, thanks. My column is always front and center on the QRZ home page.

 

My next amplifier will be a solid state unit ( I grow weary of the tuning process on tube amps), and this one is now on my list of possible "to-get's". Of course, I'd need to get a 240v line run into the shack beforehand, but I know a guy!

Guess the final selection is going to depend on how well I score with the holiday scratch-off's this year! Amps ain't cheap!

 

Hey Brando, you are right on all fronts. Amps aren't cheap, and neither is 240v installation at the ham shack. My quote was $3K to bring 240 around the other side of the house to the shack. Geez, not pleasant.

 

Get three estimates.

 

Hi Dennis VK4SX, have known Onder for many years, plus his work, Tier #1 workmanship bar none, takes all into consideration, Thermalese wire size for one thing, not afraid to buy and use First class product to get First Class end product, take a closer look at his filter boards. plus his SMP he makes use of,
I had exact same amp as in review, he sent to me in MAY 2022 to BLOW UP and send back, I did things to that amp that are immoral, Indecent and illegal, with 2 x 6KW Dummyloads I could not kill it,
so he asked me this year early 2023 if I wanted a WATER COOLED SS amp, as I live in QLD VK4, a different part of Australia when it comes to ambient air temps,
so now I use the
VK-AMPS DX-MASTER PRO-PLUS
2 x 1K80 65V Devices, R5075G Huawei PSU (4000w) same size Heat sink as AIR COOLED, but with Water Jacket under pallet.
WOW WOW,
when a VERY OLD guy gets a WOW it is worth writing about.
Lost count of how many in Service with Federal Gov BOM service here in VK,
Good luck
Dennis vk4sx

 

Thanks for the input Dennis. Amp is making it's way to the USA shores . . . good on Onder! My experience with it, over just a few days, was wonderful. Personally, I can't see mixing water with high voltages. So I reviewed the AIR cooled version! Dave, W7DGJ

 

Hi Dave, this is what AMAZES ME to this day, RE WATER COOLING,
nothing in Chassis box, or amplifier proper re WATER?
on 1/2 of the heat sink you have seen yourself, is a water jacket Aluminum milled block with 9mm Copper tube,
the only thing related to water in the Chassis is the 2 x 4" x 9mm copper tubes that protrude from the rear panel (my qrz some pics)

all cooling hardware is up to the owner, of COURSE Amp runs Air cooled if you so wish, as same cooling at AIR COOLED 2KW, but water cooling jacket fitted in DX PRO PLUS

so the new owner then designs his own water cooling hardware to suit his situation,
my situation at LAT 25 QLD east coast,
is 18mtrs of 9.5mm soft copper used in AIR CONS, filled with water sealed with a hammer, then rolled to a size that suits, mine is inside a 15yr old $20.00 75ltr BAR FRIDGE, the copper coils inside fridge,
a 8amp variable resistor on PUMP control voltage allows me to TRICKLE water thru the system by watching a 12v Flashing led, (flash speed etc)

the water exits the bar fridge drops into a 20ltr Surge fuel tank where the pump is,
EXHAUST water is also controlled for flow to lose heat in transfer to fridge,

no water in chassis UNLIKE SOME EU SS water cooled amps,
NEVER USE PC water cooling toy stuff as it just will not keep up, maybe in Siberia, but not in VK,

So no actual water cooling hardware inside amplifier chassis, only pipe protruding rear panel

Good Luck

Dennis VK4SX

PS
a Highly compressed PS2 4min over @ 4oow using ANAN G2 Pure Signal temp gets to 31C and drops to 25c in less then 30 secs once tx stops
at 2Kw TWO TONE into 6kw air cooled ALPHA 2100 Load, temp rise's steady and sits at 38C, for ages with pump at full voltage, with max circulation is enough to hold temp
remember my air temp is 30+ C degrees
plus I have a decent dummy load, not all dummy loads are equal.

Great review and option for Hams to see down another Tunnel? ahahahah with a wider vision, haahahah sorry Dave slap my wrists, I couldn't resist it,

 

Thanks for the additional info Dennis and the nice comment on the review, Dave

 

I recently got one of Onder's VK AMPs to use with a Hermes Lite 2

I opted for the 1KW model. But the build quality is the same no matter if the basic to the DX Master Pro series. "EXCEPTIONAL"
Onder is producing some great HF amplifiers and kits! and highly recommend you at least talk with him before ordering or buying your next HF amplifier.

His website hopefully will get updated soon, as offers more then what is currently shown.

On many of his amps builds or kits you can select your LDMOS device- for the 1KW I received I chose, as mentioned above the MHT1803 NXP devices a single pallet of 4 devices rated individually of 300 watts ea.

After looking at the spec on these devices and the EASE in ability to ever replace them if needed it was a an easy decision for me, Currently available form Mouser or Digi-Key at less then $30.00 dollars a piece and and easy to swap out TO-247 case design makes for an very easy to test and replace repair if ever needed unlike most other LDMOS devices. Link to MHT1803 devices here- https://www.nxp.com/products/radio-...-for-consumer-and-commercial-cooking:MHT1803A.

There is a bit of headroom with this design and as marketed by Onder at 1KW- the amp will safely trip if PO reaches the full device ratings.

The built in RF sampler port @ -55 db. works very well and is linear in its output across HF a treat for use with for Pure Signal.

As mentioned by others the AMP is very quiet, even if you get long winded and the fan goes to higher speed noticeable but certainly not appalling the temps are very stable.

Too give you some idea, this amp for me replaced a Acom 1000- The VK Amp in size is slightly wider, taller and deeper, the fan noise is quieter then the A1000 , and perhaps on par with the A1000 or just slightly more when going into high speed.

Very Please with my VK AMP here.

Less cost then a Mercury III - already has a built in sampler, no long 8 month plus wait list, Runs cooler than a Mercury 3 and is a a true performer!

Rick N8SDR

 

Hi Rick, I agree he makes great products! But I urge you not to make it appear it's better than a Mercury amp. The Mercury products have a history and great success and their customer base are all rabid fans. Onder is now a proven amp designer . . . let's see if he can build out the company and not get into wait lists as you refer to here. Dave, W7DGJ

 

Nice amp. Looks like a Mercury LUX (similar touchscreen) without the chrome handles. You get more power headroom...2KW capable...and it's $50 USD less than a LUX, with no charge for shipping. Overall, An excellent value. I'm not too choked up about it using 8 LDMOS devices to achieve that power (4 times the LUX devices), but I guess if it's engineered properly you shouldn't have a problem.

His website only shows modules for kits, like the Mercury website used to show before offering complete kits and factory assembled models. My only concern would be shipping it back to Australia if it needs repair.

Bob K7JQ

 

He is using MHT1803a/b ldmos equivalents to MRF300a/b Lddmos fets. Both are from the same manufacturer. Only difference is a MHT1803 runs on average 23 bucks each. I converted my ALS1300 over two of his pallets. Solid 1800 watts, and NO failures. And the construction puts the MFJ quality to shame.