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Author Topic: New QRO 8877  (Read 12663 times)
QRPNEW
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Posts: 51




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« Reply #30 on: August 08, 2012, 03:09:13 AM »

It would not have cost much more to  use a bandswitch that  had the WARC bands on it.

My eyes are good, there are no tuned inputs for the WARC bands.

Having a WARC enabled bandswitch makes tuning the amp a lot easier. It really matters when you also want to tune the AMP into any antenna that has a slightly higher VSWR.  AMPS that dont have a WARC
dedicated bandswitch can  be all over the map when the antenna  has a slightly high VSWR.  Especially when using a the next available close bandswitch position.  Besides its  a far from optimum way of doing things from
the perspective of  your transceiver and maintaining optimum drive to the tube.

This amp probably uses a Radioswitch bandswitch. If you call them and check  the prices, you will find that there is no price difference when buying a  6 position switch versus a  9 position bandswitch. Why not also put in an auxiliary
band position say for 5mhz. Sometime in the future the power limit might be increased. This would make the amp more valuable. Another possible way   is  to make the amp general coverage with multiple bandswitch positions
that give complete 1.8 to 30mhz coverage. Alpha produced such a amp.

It might be nitpicking, but if you going to release a new amplifier you might as well do the job properly. I am not surprised at the success of amplifiers like OMPOWER  and Acom. They  seem to do everything right.
I just dont like their tube choices! I really wish that Acom would produce a 8877 all band amplifier, that would be some amp.

It looks like the amp is released so the this discussion  will accomplish nothing. Enjoy your new QRO amplifiers the 8877 is a  very good tube. Maybe QRO will bring out a 2 x 8877 amplifier like the old Alpha 77SX.

Some of you need to get new glasses, if you look at the rear panel shot there looks to me as there is a tuned input for every band, the caps for the PS can be seen on the side veiw pic as well, underneath the diode strings. Boy you guys gotta look closer at those pics, your all kinda ruff on this guy. His amp are very well designed and not some noise boxes like the comanders were, he seems to use well designed blowers with smooth bering race in his amp's. BTW the Dentron DTR2000 used an 8877 and had no tuned input, just a small toroid if I rememeber right and the 77DX/SX had a swiths by the tube that would let you go directly into the tube which was around 54 ohms that would bypass the tuned input for use on other parts of the spectrum removed a little away from the ham bands for MARS. As far as the band switch I bet my bottom dollar that its the kind that snaps into position not some girly band switch that feels week and as far as the warc bands go you cant runn more than 200W on 30mtrs and 17&12 are close enought to use 20&15 mtr taps, my call would be to give tha ham op's a REAL BANDSWITCH and that one in the pic doesnt look girly to me. I would like to know how many of you guys that are throwing stones and being BB on this new amp even ever built a home brew 8877 plus Alpha has been using toriods in there tanks for a looonnnggg time.
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KE2TR
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Posts: 135




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« Reply #31 on: August 08, 2012, 05:58:59 AM »

I said some not all need, well the Acom amps were inspired by Alpha's own when they came out with the 91B, once they had the design down they ran with the 2000A but have not really designed another hi power manual tuned amp since the 91B, just single tube job's so Acom kinda put the screws to Alpha right after the 91B project was done. I find it funny that a few just dont like the russian tubes, if you can find a real good supply and stay away from the old military junk that was coming into the USA at one time the 4CX800's will produce within 100watts of a single 8877 but if you place the 3CPX1500A7 into a Rf deck with a robust supply then you will have some headroom. The 3cpx series tubes are used allot in MRI's and there  rotated every 500 hours so pulls have allot of life left in them for a backup or for homebrewers. Over 20 years ago I built a HB 8877 with 4KV supply under load with a CCS rated xfmr at 1.5 amps, into a dummy load that amp would pin a 2.5K Bird slug, back in the late 90ies I had a hi serial # 77DX tha would put 2700W out into a dummy load but you had to drive it a little hard, the HB8877 only had 100w of drive. The 91B I owned after that amp would put out 2600W into a dummy load with 100w, had better protection, more able to withstand contest abuse  and had a much smaller footprint then either amp. This new amp looks like the size will be of there other amps in his line and maybe because of the bandswitch is more designed for the contesters than DXers.
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N4RSS
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Posts: 258




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« Reply #32 on: August 21, 2012, 06:18:33 AM »

I notice there is now more information on the QRO website.

Interestingly, the HF-2500DX is no longer on the webpage.

Ray hasn't responded to my email asking about the power supply voltage, but I notice there are 10 450V capacitors Smiley.  The 2500DX has 8.  I'm guessing 3500V
« Last Edit: August 21, 2012, 06:21:10 AM by N4RSS » Logged
ZENKI
Member

Posts: 924




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« Reply #33 on: August 26, 2012, 04:00:20 AM »

I would not be surprised if he did not go ahead with the product. The amplifier market is flooded with suppliers.

If he wanted to do well he would produce a copy of the Alpha 77 amplifier with the 1 and 2 holer. Better still would be any amp with a 3cx3000 in it. This tube can be rebuilt and its cheaper than the 8877.

Really he should be putting enough electrolytics or space in the amp to take the plate voltage right upto the 4000 volt no load level.  That would need something like space for a 5kv capacitor  bank.
Those who want to upgrade or build their own power supply can do so.

I own a Henry 4K Ultra and in my opinion it was the best Amp that Henry  built. It was the best built 8877 amp in the world. I doubt if we will ever see a amp  of the quality of the Henry 4k ultra on the market ever again.
All we see on the market are these badly design wannabe bad boy amps who just have all sorts of  marginal components and design issues.


I notice there is now more information on the QRO website.

Interestingly, the HF-2500DX is no longer on the webpage.

Ray hasn't responded to my email asking about the power supply voltage, but I notice there are 10 450V capacitors Smiley.  The 2500DX has 8.  I'm guessing 3500V
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N4RSS
Member

Posts: 258




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« Reply #34 on: February 06, 2013, 05:46:06 AM »

So, I've sent two emails requesting information over the past several months, from corporate email account, not gmail or webmail, 'cause he says he filters webbased emails, and haven't had a reply.

Now, I notice he's removed the phone number from his website.

I'm through with this guy.  He's not even very friendly when I have spoken with him in the past, to be honest
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W6UV
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Posts: 538




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« Reply #35 on: February 06, 2013, 07:40:23 PM »

Now, I notice he's removed the phone number from his website.

Say what?

Right at the top of the home page I see:

Tel: 419-913-1821
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N4RSS
Member

Posts: 258




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« Reply #36 on: February 07, 2013, 05:15:03 AM »

Now, I notice he's removed the phone number from his website.

Say what?

Right at the top of the home page I see:

Tel: 419-913-1821

What a surprise...

http://web.archive.org/web/20130119071357/http://www.qrotec.com/
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K6AER
Member

Posts: 3501




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« Reply #37 on: February 15, 2013, 08:46:52 AM »

I understand the reason for not bothering with the WARC bands. The input tuning matrix board looks to be the same as what Ray has used on other grounded grid designs. This was probably a cost saving decision. Big  gun DX stations don't do contesting on the WARC bands. With the exception of 17 meters the other bands for all intensive purposes are QRP operation.

I don't know what the "reduced output" on 17 meters is but I'll bet it still makes 1500 watts instead of 2500 watts on 20 meters. Nobody will miss the illeagle 2.04 dB when you are using a 4 element monoband er at 100 feet with 1500 watts.

As for input tuning on 17, use the transceivers antenna tuner once you get the output tuning set.
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