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Author Topic: Solid State or Tube ??  (Read 3296 times)
AE5RE
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Posts: 14




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« on: November 08, 2008, 10:37:13 PM »

Hi there,

  I has narrowed my search to 2 amplifiers the Tokyo Hy-Power 1.5Kfx (900-1K watts) and the ACOM 1000 since I want to have 6m.  I am aware of the rumor or reality of the GU74B/4CX800. I am looking for the one that will have a better resale value. In other words if you were looking for a used amp and had the above 2 options which one would you buy?

 Any help/suggestion would be really appreciated. 73
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N3JBH
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« Reply #1 on: November 09, 2008, 06:31:13 AM »

I would not buy a Amp with a 4CX800.
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WA4ONV
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Posts: 51




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« Reply #2 on: November 09, 2008, 06:47:14 AM »

From the research I've done I think Solid state is the way to go. I presently own an Al-1500 QSK but my next amp will definitely will be a solid state amp like the Tokyo HP. I saw them in Dayton being operated under 100 percent duty cycle into a DL and they were just loafing along at around 1000 watts on the Bird meter. Good luck !

Joe, WA4ONV
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W6OP
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Posts: 352




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« Reply #3 on: November 09, 2008, 08:27:54 AM »

I have had the THP 1.5k since they were first available in the USA. Instant on and it works great. I also have their matching auto tuner. Doesn't have a real wide range but works fine since I have mostly resonant antennas and can go from one end of the band to the other without a problem. The SS amps are sensitive to SWR, over 1.8 and the protection circuit fires off. But you never have to tune up on top of the DX with them Smiley

Pete W6OP
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N3JBH
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« Reply #4 on: November 09, 2008, 10:13:00 AM »

"you never have to tune up on top of the DX with them"

Why would you do that any way's? Surely if you could afford the amp you could get a dummy load to,
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WB2WIK
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« Reply #5 on: November 09, 2008, 11:04:10 AM »

The Yaesu Quadra VL-1000 and Icom PW-1 also both include six meters and both include an ATU inside the amp so an accessory ATU is not required.  As such, either might be a better deal than the THP plus an accessory ATU.

As for ACOM, their amps are very nice (never owned one, but used them at contest stations -- easy to use, worked well) but I understand "service" might range from poor to nonexistent so if I were to purchase an ACOM I'd do so with the understanding that the Tech Support and Service Dept. would be "me."

WB2WIK/6
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K7JQ
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« Reply #6 on: November 09, 2008, 12:13:36 PM »

I've had the THP HL-1.5KFX since August, 2007, with nary an issue or problem. As a previous post said, SS amps are more sensitive to SWR, and this amp will fault over 1.9:1 SWR, so a tuner or broadband resonant antenna (ex: SteppIR yagis or verticals) will be a necessity. It has tons of fast acting protection circuits, should a bone-headed situation arise. If you use it with a later model Icom, Yaesu, or Kenwood xcvr, it can change bands automatically with the radio, giving you essentially a KW xcvr. The fit and finish and internal wiring are of first rate commercial quality. Support from THP Japan and domestic rep is also excellent. No tune (with reasonable SWR), no high voltage snaps, crackles, or pops convinced me. Only downside...a bit pricey, especially if you purchase the matching ATU. As you might guess, I kinda like it....highly recommended.
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K6AER
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« Reply #7 on: November 09, 2008, 06:13:31 PM »

You did not mention if you were using the amp for CW or SSB. If your bag is SSB, I would go with the tube amplifier. Better linearity, lower IMD and a softer head room with a tube amp. Your modulation will not maintain within a dB or two and tubes give better soft compression on the output. A 1200 watt solid state amplifier needs to be run at 800 watts to leave some linearity for aggressive voice peaks.

As for the 4CX800A7, yes the tube is a bit harder to find with prices going at $230 per tube, but there are still plenty around. The problem with solid state amplifiers is the devices in the output could turn up as a non production status over night. Many older solid state amplifiers have been rendered un repairable due to obsolete transistors.

Also tubes are very forgiving of mistakes. Transistors just protect fuses.

It has been estimated that 30% of the 2.5FX THP amplifiers have blown their finals when operated in contest conditions. Unless your band hopping a lot, I would go with the tube amplifier.
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K0BG
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« Reply #8 on: November 10, 2008, 05:45:49 AM »

Mike, I'm sure you know that some of the most popular tubes of the past 2 decades are now in the nonobtainium category. The 8873, 8874, and 8875 come to mind. The 8875 literally was discontinued overnight, and no announcement was made prior to. It just went!

My Icom 2KL uses 2SC2652s, and if you search the net you'd get the impression they haven't been made in some time. Yet, one import company has over 10,000 piece in stock. Yes, they are pricy, but they always were in relation to the COL.

The key issue is, knowing which is and which isn't nonobtainium. Personally, I wouldn't touch anything with 4-glass, or 88xx (8877 excluded), or any amp with Svetlana printed on the tubes. And I wouldn't touch any SS amp with Motorola finals like the TT Hercules series, Metrons, etc.

Alan, KØBG
www.k0bg.com
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K7JQ
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« Reply #9 on: November 10, 2008, 10:44:10 AM »

All very valid points, gentlemen, and from knowledgeable experts. I'm sure AE5RE will take them all into consideration when deciding on a purchase.

As for the THP HL-1.5KFX, it uses latest technology(4) SD-2933 MOSFETS for finals, manufactured by ST Microelectronics...one of the largest and reputable semiconductor companies in the world. Each one is capable of 300 Watts output at 50 volts, so the amp has a "headroom" of about 200 watts when driving it to 1 KW PEP or 900 watts CW carrier as recommended....not "tons" of headroom, but should be sufficient under normal operating conditions at low SWR's. It is the largest of their SD-293X series, and Yaesu uses SD-2931's in the FT-2000D and FT-9000, so it's unlikely that ST will discontinue the series anytime soon. BUT, you never know! Everything becomes obsolete eventually, even tubes. Incidently, the new THP HL-1.1 KFX runs 600 watts PEP, using the same (4) SD-2933's....lots of headroom there, just a lighter power supply, no 6 meters, and no capability to change bands from the radio.

Just my 2 cents of additional information. Good luck with your eventual decision.   73, Bob, K7JQ
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AE5RE
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« Reply #10 on: November 10, 2008, 12:39:04 PM »

Interesting replies, thanks everyone. I am one of those that believes SS is the future. After all I have researched and comments here I have reached the conclusion that I should not run the 1.5Kfx beyond 800W in SSB/CW and no more than 600W in RTTY for casual use.  If I go contest I should not do more than 700W in SSB and 500W in CW/RTTY. But this is just me thinking aloud. Acom 1000 has more room for the same price but GU74B is the big question but the tube and amp have EXCELLENT reputation. On the other side, try to buy SD2933's, I "google it" and found only 2 companies in US that sell it and they have 47 pieces in stock only...(interesting).... still a hard decision for $$$K I will just make a decision and live with it...SmileySmiley

Thanks everyone!!!
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K7JQ
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Posts: 1304




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« Reply #11 on: November 11, 2008, 01:54:03 PM »

In regards to the availability of SD-2933's, the ST Micro website is showing a new evolution of the SD-293X generation...the SD-294X series...specifically the SD-2942 and 43. They have a power output rating of 350 W, and higher gain than SD-2933. No mention of discontinuing '293X series. Might be a direct substitute if necessary??? Perhaps the availability of SD-2933's on the open market is affected by THP hoarding a ton of them for their amps??? :-)

I for one am not concerned about this issue, as THP is a long standing reputable company,and if my finals go south, I'll send the amp back, or they'll send a replacement PA module for me to install. Hope this helps your decision.  73,  Bob, K7JQ
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N3JBH
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« Reply #12 on: November 12, 2008, 11:15:55 AM »

"found only 2 companies in US that sell it and they have 47 pieces in stock only..."

Ok well Digikey had only 47, Let me ask you this how many do you think they sell? I am farily sure that they dont sit on a lot of items like that in stock being there a limted market, But i bet allot quailty places can get them for you if need arises.

How many 4CX800 tubes did you find stocked by US companies?
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N6AJR
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« Reply #13 on: November 17, 2008, 05:46:34 PM »

well I have several of each and the difference is in the operation, but not the tube or transistor compliment.  I have an AL 1200 , a tl-922,a IC-2KL with at500,  an als 600 and a alpha 87a. I use the alpha 87a the most. legal limit, and fully automatic and self protects too. it uses tubes, very expensive tubes, but Molly makes them in colorado I believe. I prefer  no tune amps in a contest and manual tunes for rag chewing.
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K0ZL
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« Reply #14 on: November 26, 2008, 06:15:22 AM »

Take a look at the Expert. We are on version III with the latest engineering updates:

www.spe-na.com

Thanks

Bill K0ZL
SPE-North America
CustomRF Solutions
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