| K9WMM |
Rating:      |
2007-04-09 | |
| Great brut force amp |
Time Owned: more than 12 months. |
I have had the amp for 4 years. Bought it new from QRO.I had a few minor problems. A relay had a bad internal connection which I resoldered. I was having probelms with the 400V PS and blown fuse. Ray gave me advise on how to fix it. The amp put out 2,500 watts into a Bird 5KW oil filled dummy load and measured with a Bird as well. It loafs along at 1,500 watts. It is not fancy with micro processors, but something you can FIX yourself. If you can't tune your amp, what good are you? This is a Ham's amp! I have built a few of my own linears so I know a little about them and construction. This is a very good amp!
Ray gives you the best service and advise either on the phone or by email. If you want a piece of equipment you can fix and something that will last your entire Ham carear, this is it! |
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| K0RU |
Rating:      |
2006-12-26 | |
| Excellent Product & Service |
Time Owned: more than 12 months. |
Hello I purchased my QRO Technologies HF2500DX amp 1998/99 almost 10 years ago. My age is 46 and I've been a ham for 36 years. I operate mostly cw and high speed cw at that. While operating I only operate QSK period VOX puts me to sleep. I've owned many of amps by the X-brand companies and all claim to operate QSK etc, etc. I say BULL!@#T... IF you can't operate QSK full throttle at 80 wpm then your not QSK period.
Well I called RAY at QRO and began a conversation with him regarding QSK I explained to him what I do while operating, my operating practices and exactly how I operated. He stated the amp will do very fine for you, if for any reason it won't I'll gladly modify it to your expectation if you’re not totally satisfied. Hmmm, encouraging but I'm not ready to drop the big bucks just yet... I had attempted to request a manual from X-Brand amp manufactures to include all drawings and schematics... Not one of them would send me a manual let alone any type of drawings. When I requested this same info from Ray his immediate response was "yeah sure, I'll send one out in the mail tomorrow" ok, I can tell that isn't going to happen. Anyway I get off the phone and get on the air and operate. Wow, to my total surprise in a couple of days a package arrived from QRO Technologies in it was the owners manual, drawings, schematics, hell even the circuit board layout drawings I was totally impressed. I read the manual front to back drawing by drawing it appeared that if I were to having any troubles with this amp I would have everything I needed to diagnose and troubleshoot this amp and make the repairs myself if I needed to. Time to spend the big bucks....
Placed my order, QSK, 10 Meters, whole ball of beans... The amp arrived within days. You get the feel for how proud Ray is of his amps when you first receive them. First they are packaged excellent. The transformers are shipped separately (they are heavy) and the tubes are packaged separately. When you receive the amp, you will get your first taste of the quality that goes into this amp you have to remove the cover and install the tubes and transformers while doing so you can help but appreciate the quality of components and the workmanship that goes into this amp it is truly a Work of Art.
Now I operate QSK and I operate high-speed QSK which means I put the pedal to the metal and hammer when I'm working a contest, I'm full throttle (yes fast as the keyer can go on the mark 5 which by the way is only 45 wpm) and the amp sails along smoothly riding along punching thru pileup after pileup. Ok, so now I'm tired of this slow speed keyer on the mark 5, its just way to slow, time to buy a real keyer. I purchased the best of the best when it comes to keyers LogicKey K5, this thing will smoke it.. I send using a Bencher Iambic paddle, and I can send upwards of 60 wpm in a RAGCHEW not this 599 KS 73 crap, I ragchew for hours on end at those speeds using my paddles. Well the amp was ok upwards of 45 now at 50 and 60 hmmm that’s another story. You see the transition from Receive to Xmit on the amp is done using a Vacuum relay if you fire the relay at the exact same moment your transmitting RF thru it, there is the possibility of what is called a FLASH OVER on the contacts... Yup... when operating QSK in the past with my Yaesu FT1000MP Mark 5 I was using the XMT GRD output on the back of the rig and sending that to the XMIT GRD on the amp which completed the sequencing circuit for the QRO to go into Transmit mode thus firing the vacuum relay. Simple and effective at least when running QSK at below 45 wpm, not at higher speeds the relay will flash over and STICK!
Mine stuck, now I'm dead in the water the amp won't key properly and nothing I can do fast enough to prevent blowing the 1-1/2 amp AGC fuse on the LV/BIAS circuit board. Replace the fuse and life goes on... Anyway this becomes annoying at times and I would forget to not push the speed to high for the sake of that poor little fuse blowing again. Ok, enough of this, placed an email to Ray who immediately returned an email stating he was on the road and would gladly give me a call once he was back. We'll Ether he got bored and forgot or was just impatient in any case he calls me almost immediately and begins explaining blow by blow, wire by wire, step by step on how all this sequencing process takes place. He stated the vacuum relay most likely had experienced a flash over and was stuck. I then fired up the amp and began thumping the amp with a transmit signal (NO RF, just keying it rapidly) and BINGO the relay released and away she went... Hmmm, I asked Ray if I could purchase an extra vacuum relay to put in parallel with the one in there now to reduce the current on the relay contacts his response was simple.... Waste of money, first off the relays are very expensive and by adding a second relay doesn't guarantee that it wont happen again at the extremely high speeds one may nanosecond release before the other and the flash over will occur again. I thank him for all his help, and offered to pay him for his time (being a service guy myself I know time is money and I was more then happy to pay for that time) he replied that is not necessary enjoy the amp and if you have any further problems with it ship it to me and I'll gladly address it for you. 73...
Okay, now I'm off the phone and begin to think, sleep, think, sleep, think they has got to be away to keep this from happening without having to send this back to Ray I need to do this on my own... Bang, the light comes on; my Yaesu FT1000MP Mark 5 has a DATA plug that is an 8 pin DATA plug that offers BAND DATA and XMIT DATA for use with the Yaesu QUADRA Amplifier. On this DATA PLUG is pin 3 which goes to GROUND when TRANMIT HAS BEEN triggered (NO RF YET) just as xmit has been initiated. Then there is the PIN 8 which is looking for a GROUND BACK to acknowledge that is it now OK TO TRANSMIT RF.. (This sequence happens very rapidly, its referred to as a HANDSHAKE) that allows the radio to coordinate its RF OUT ENERGY with a sequencing event that may have to take place IE, TRIGGERING A AMP, or STEPPING A AUTOMATIC TUNER, or SWR VERIFICATION the possibilities are endless. In my case, it was excellent choice to coordinate the keying sequence with the QRO for full QSK operations oh and the best part of this is that the rise and fall time is fully adjustable from the menu on the Mark 5.
Okay, my mind is running full speed now, I designed a circuit that looks at the ground signal from Pin 3 from the DATAPLUG and this ground then triggers 2 each MOSFETS which can handle upwards of 100 Volts @ 6 amps easily. When pin #3 on the dataplug goes to ground it fires the GATE signals on the MOSFETS which then triggers the XMIT GRD signal to the AMP's vacuum relay circuit. Interesting is now I need a feedback to the rig to acknowledge the amp has been triggered. Bingo, this comes from the GREEN LED on the front of the QRO amp, the relay which drives this GREEN LED lamp Opens and Closes 12 VDC to the lamp circuit board for just that purpose, I installed a small 12 VDC double pole relay on my circuit board and drive that relay with the same 12 VDC which drives the GREEN LED (xmit lite) on the amp from the small relay on the LV/BIAS circuit board (which by the way is the same relay that sends the FIRE command to the vacuum relay). Now I have a feed back signal, simply use one of the normally open contacts on my relay to trigger a Ground OUTPUT to the mark 5 telling it that the Vacuum relay has been trigger and RF is okay to fly. This all works fine and dandy when you’re ONLINE with the amp, but when in STANDBY mode the mark 5 wouldn't see the GROUND because the vacuum relay wouldn't be used as the amp would be in standby doing nothing... Solution, Yep Ray thought of everything when he built this amp, he installed a double pole, switch for the Operate and Standby mode switch, the second set of poles on this switch is empty and has a Normally Open and Close contact, simply run two wires from this switch to my Ground OUTPUT to the Mark 5 and the amp would then provide a GROUND OUTPUT to the mark 5 at all times if the amp were off or in STANDBY MODE. I installed 2 RCA jacks on the back of my QRO that are labeled QSK LOOP INPUT and QSK LOOP OUTPUT which will work with any other QSK rig that has this capability.
How does it work, it totally ROCKS, this amp will hammer at 80+ wpm at full QSK without missing a step. Flash over? What the hell is that, it don't exist anymore the sequencing controls all the signals back and forth to and from the rig and amp so each knows the exact state of the other at all times preventing the flash over crap.
What does this all mean...
#1... The drawings and schematics are so detailed I was able to build and design this circuit myself within a couple of hours and had it installed and running without any conversation what so ever with Ray @ QRO as a matter of fact, he doesn't even know I made this mod until he reads this...
#2... Hands down, this is by far the best amp I've ever owned in 36 yrs of contesting, rag chewing and chasing dx...
Conclusion??? SEE YOU IN THE PILEUPS; ILL BE THE ONE THAT GOT'M WHILE YOU’RE PLAYING WITH YOUR VOX RELAYS...
Simply put, BUY THIS AMP YOU WON'T REGRET IT!
73 - K0RU - Rob (old call - W8YRB)
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| N4ZKF |
Rating:      |
2006-12-17 | |
| Flawless |
Time Owned: 3 to 6 months. |
This amp is built with the word overkill in mind.
Bulletproof. I lost a balun one day running legal limit and it just tripped the circuit. I replaced the balun, fired it back up and went on with my business. I drive it with 45 watts on my FT-2000 and I love it!
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| K5JAX |
Rating:      |
2006-12-03 | |
| QRO is top quality |
Time Owned: 0 to 3 months. |
| I have just had my amplifier for a few weeks. I have been a ham since 1960 and built big amps back then. The right components and design knowledge are key to making a good product. I looked at most all of the big tube amps and the new transistor ones from Japan. I decided that you couldn't beat the quality for your dollar with the QRO 2500DX. It loafs at about 800w PEP out and you hardly see the needles move at that power level. I have had it up to the legal limit, but I don't need that for ragchewing on 40m. It interfaces perfectly with my Kenwood TS-850SAT. Both final keying and ALC work well. Bird used for power monitoring. Distortion products are lower (probably TVI also) when you don't need to run everything at the max power out. More after a year of operation. 73's Roger |
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| WA8EBM |
Rating:      |
2006-11-10 | |
| Solid no compromise high power |
Time Owned: more than 12 months. |
Owned it just over 2 years. Loafs at 1.5KW with low drive. I can drive it with about 12 watts out of my K2 and get about 750W- sometimes more out of the amp. Solidly built and when you turn the bandswitch you know it's heavy duty.
Just a couple days after 2 years it blew a fuse. Got with QRO and narrowed it down to a bad Russian tube socket on one of the GU74's. Mailed it back to QRO and they were kind enough to repair it under warranty. Had it back up and running in just over a week. No complaints there!
A few people have mentioned that the fan was quiet. I wouldn't really say that. It has to be noisy to circulate 1500 watts of heat around the tubes and plenums. There is a low/high switch for the fan. I use headsets most of the time when the amp is on. I have pulled the fan out of the amp and found the sleeve bearings to be dried out and oiled them and quieted it down considerably. I also remounted the fan on some high density 1/8 inch foam gasket. The blower is a standard Dayton available at Graybar. Tried to find a ball bearing fan that would fit but this is the best available. One note is that the T/R relay has some SWR smoothing caps across it in the de-energized position for direct transceiver feed thru. I found I could not pass a six meter signal through the relay. I have 6 meters on my PRO3 and FT2000 and you need to put the antenna for 6 on your alternate antenna output or in my case with the SteppIR that covers 6 meters, put in a switch to bypass the amp totally on 6.. I looked at all the tube amps, Acom, Alpha and other lower priced units and chose the QRO because of the oversized transformers and plate circuit components. The design has proven itself solid and I have found nearby customer service to be a big decision swayer. I also have a Icom PW-1 solid state KW Amp that I use with my PRO3 but I feel most comfortable with the QRO for brute force high power key-down service. |
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| NK8T |
Rating:      |
2006-02-11 | |
| A gentle "GIANT" |
Time Owned: 6 to 12 months. |
| This amp is the 4th amp I have owned and by far the best. Its construction and attention to detail reflect Ray's pride in putting together a quality product. At first I thought tuning was going to take some getting use to, but not at all. It tunes simple and straight forth just following the easy step by step instruction in the manual for the first few times. It’s built in protection systems makes this an amp any amateur can use without worry. Recently I purchase a Yaesu FT-1000 Mark V Field that will operate in SSB A mode. The maximum power in this mode is limited to 25 watts output to produce the extra clean SSB signal. With the QRO amp, I can run SSB A mode and still run full legal limit. This is a beautiful amplifier and at its price is one of the best investments you will ever make. |
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| N0XB |
Rating:      |
2006-02-08 | |
| Takes no "back seat" |
Time Owned: 3 to 6 months. |
I am not sure what superlatives I can add to this fast growing list of satisfied users, but I'll try.
After seeing one in a friend's shack, I knew it was the amp for me. I bought one, and have since acquired a second. One for each rig on my desk. Great!
Easy tune up, highly repeatable settings, lightning fast "error protection", very quiet QSK with vacuum relay included (great feature, Ray), QUIET operation even on high speed fan, and LOTS OF POWER.
Really guys, if you don't want to lay out the obscene price for an A***a or Emtron or Acom, you really should take a look at the HF2500DX. All power you need/want and more.
Larry, N0XB
Northfield, MN |
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| W8FAX |
Rating:      |
2005-12-11 | |
| Great Amp |
Time Owned: 0 to 3 months. |
| The amplifier is built like a quality amp in this price range should be built. Heavy componants and 1st class wiring. Shipping was on time and packed to sustain the gorrilla's working at the shipping companies. Instructions are easy to follow. CAUTION: Make sure you have a VERY sturdy table or desk for this amp. You might also consider some help when lifting it. This is my second amp from QRO (pair 3-500z's), and I am just as happy with this one as with the first. Thanks Ray for great service and a good product. |
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| W5JON |
Rating:      |
2005-08-12 | |
| Flawless |
Time Owned: more than 12 months. |
It has now been over a year since my purchase of my QRO HF2500DX and it has been flawless.
In use almost everyday for the past year, since I replaced my IC-756Pro (with spike problems) with a FT1000MP MkV Field I have not had a single "Fault" trip. Just solid performance, in spite of an occasional "operator error".
With about 40 Watts of drive it still loafs alone at an easy 1500 Watts on all bands 10 to 160 meters.
Hats off to Ray for a great product.
73,
John W5JON
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Earlier 5-star review posted by W5JON on 2004-09-02
The QRO HF2500DX is a solid performer, with an easy 1500 watts on all bands with 40 watts drive, and with look inside you can see why. It is built to perform and to last. When I purchased the QRO, based on my research I thought it was the best amp available, now I'm sure.
Now I will attempt to make a long story short.
When I first received the QRO,the exciter was my IC756PRO. Problem is the IC756PRO (some do some don't, mine did) at the beginning of each transmission (about the first .1 second) outputs a full 120 watt spike before it's slow acting ALC can bring it down to the 40 watt (or whatever)output level it is set at, for the QRO (or any other amp). Needless to say this "120 watt spike" would trip the QRO every time.
Now the good part...After two phone calls and two EMails to Icom, they finally admitted to the problem. Their solution was to connect a 9 Volt battery with a pot into the ALC on the back of the IC756PRO and give a "constant" ALC,to compensate for the slow ALC in the IC756PRO.
However, my solution was to get rid of the IC756PRO, which I was never overwhelmed with anyway, and purchase a Yaesu FT1000MP Mk V, with which I am very pleased, and has exceeded all my expectations.
Many thanks to Ray at QRO who made a valiant attemp to solve Icom's problem (back and forth to QRO twice). He really went beyond the call of duty to try and solve a problem that was Icom's not QRO's.
Bottom line is the QRO works great with the Yaesu FT1000MP MkV, with never a trip.
73,
John W5JON
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| WD0CT |
Rating:     |
2005-07-24 | |
| okay big bruiser |
Time Owned: more than 12 months. |
I owned an early one in 1997. It was very heavy, looked great, and had great power.
The tuning procedure was a bit of a pain.
I had to send it back for repair once. Never did find out what was wrong with it.
I sold it to a friend and he loved it. |
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