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You can
write your own review of the Kenwood TL-922A.
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QRPNEW
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Rating: 2/5
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Nov 21, 2009 16:53
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Outdated Design
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Time owned: more than 12 months
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This amplifier seems to have a cult following. Theres no doubt that its physically well built, however electrically its an marginal amplifier.
The prices that people are asking for these amplifiers borders on insanity for such a old weak amplifier design.
The many faults include
Poor RF design
Poorly rated RF parts
Poor or NO protection circuits
Lots of trouble with parasitic problems
No spare parts available
Tubes that are getting expensive
If you ran this amp in a contest you will probably burn it out.
If the bandswitch or power switch goes you in deep trouble. If you have a grid filament short you could be in for some real trouble. None of the spare parts are available.
The load C spacing is marginal, if you even try and tune it into a moderate 2:1VSWR you will ARC this crappy capacitor.
The relay switching is slow and will damage newer model radios. No inrush limiting and many other design failings.
Just do a google on the TL922 and you will come across several pages on "mods" to try and correct its many design failings.
I like buying blown up TL922's and converting them to 6 meters. However on HF I would only recommend the TL922 to my worst enemy. If you have one keep it, however I would not invest money in such a marginal amplifier.
Today if I was looking for a 1 kilowatt to 1300 watt amplifier I would be looking at one of the new solid state designs like the SPE or Ameritron.
If you need a real 1500 watt amplifier get the AL1500.
Bottom line is that I hate using equipment that makes me nervous every time I turn it on or use it. The TL922 is such a beast, its better to look at than USE!
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EA1XF
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Rating: 5/5
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Nov 21, 2009 16:21
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Nice Amp and working better and better
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Time owned: more than 12 months
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I bought mine in 1999 and it has been running flawlessly until a couple of months ago when a choke burnt out, so I thought it was time to send it for a complete overhauling. Every little part, board and values were checked in order to have it as the very first day when came out from factory. Input swr was re-adjusted and some components were replaced for new ones, like the zener bias diode, capacitors and even the final tubes, although there was no need to replace them yet, now has a new pair of matched Amperex 3-500 ZG and I am keeping the old ones as spare.
It loads and tunes very smooth and I always tune mine by the “Plate – Load – Plate procedure” to maximum power output, with the meter switch on the RF position. When the amp is perfectly aligned, this method will make the Ip automatically dip to the minimum. With the transformer set in the 240 volts position, these are the readings I get on 14.200 MHz, on the SSB position and on my PowerMaster meter:
Input 86 w ---- 1.185 w (output) 130 mA (IG), 0.55 mA (IP)
Input 108 w --- 1.429 w (output) 175 mA (IG), 0.62 mA (IP)
(Note that the IG and IP readings do not exceed the ones given by the manufacturer)
With 120 watts from my TS-830S, I saw 1500 watts coming out from the TL-922. Not bad, isn´t it?. I wonder how much power will put out if connected to 220 volts, but I will not make the experiment, hi,hi.
The only thing I dislike is the loud relay. It was not worth to change it for a quiet one because it works perfect and is quite solid.
I enjoy very much working with it and I am sure that if we keep the
recommendations suggested by the manufacturer, this amp will last for ever. It is built like a tank and makes a nice looking piece of gear on the shack.
73, Carlos
EA1XF
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ON4UQ
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Rating: 4/5
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Jun 24, 2009 01:21
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Easy to use, compact, nice to see...
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Time owned: more than 12 months
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My former amp was the 1200 Watts made by AMP UK. I had been too badly surprised about what I had seen when opening the case...
I purchased the TL-922 second-hand from a CB-fanatic.
Of course, I knew the tubes were poured down to the last eV (...!) but I also knew the most strategic part (= the bandswitch!) was brand new because it had never been turned!
What I saw in it was amazing: dual shielding, tank coils made of silver-plated copper pipe, redundant anti-idiot proof circuit and interlock.
The way this amplifier was built was just the same as the professionnal transmitters I operated while sailing as a radio officer in the Belgian Merchant Navy...
This amp is easy and accurate to tune, nice to see, built as a german WW2 bunker. Sixty years later, most of them don't anymore exist, but for sure the big loud switching relay will survive the next war...
Another point to mention is that the upper cover never becomes warm: it simply means the cooling is efficient.
My 3 cats loved to sleep on the case of the AMP-UK after I switched it off; they don't put any interest in the TL-922 sleeping place..
It gives about 900 W out in CW, but where is the difference between 900 and 1000 W out? Less than 1 dB.
The only negative point is that the HV transformer is a little bit short. The "protective clixon avoiding the transfo to overheat" is not a protection circuit, but simply proves that the transfo overheats because the iron is too small and the secundary wire too thin for giving the full input power during a long transmitting time. That's why I only gave 4 instead of 5...
The "Latour" voltage doubler gives a sufficient HV regulation but this can be improved by using new (bigger value in same dimensions)electrolytic capacitors, but anyway, if you want a table-mount but not too bulky amp, you have to make some compromises...
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K5LG
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Rating: 5/5
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Jun 3, 2008 06:44
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good amp but noisy relay
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Time owned: more than 12 months
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The 922 is a good solid amp that I have used since 1988 . It will put out about 1200w-1300w with new graphite tubes. It is a well constructed amp and I have never done any mods to it.
I recommend it highly
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MW0KIK
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Rating: 5/5
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Dec 29, 2007 04:17
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Great Amp
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Time owned: more than 12 months
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Had this amp for a couple of years and used on various bands. Never had a problem with this linear and found it simple to use and tune with various radios including the yaesu ft2000 and the icom 7800.
Will be selling this shortly as I need the cash to put towards the pw1 to match the 7800.
Bottom line is its a reliable and easy to use linear with easy to replace and cheap to aquire tubes!
73
Leigh
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VE7AGW
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Rating: 5/5
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Oct 7, 2007 09:50
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Correction
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Time owned: 3 to 6 months
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I stand corrected on the TL-922A, it goes from 160 to 15 meters, NOT 80 to 15. Both the TL-922 and the TL-922A have 160 meters.
The TL-922A dosen't have 10 meter but the TL-922 does. The TL-922 was the export other than USA model and the TL-922A was for the USA only.
This was done so the Kenwood could sell the amps in the USA. Most amps manufactured for the USA market are not allowed to have 10 meters on them. Even though it takes a fair amount of power to excite the amp and most if not all CB radios only have an output of 4-5 watts.
There is a mod that will allow the TL-922A to work on 10 meters and most if not all the amateurs who have the amp do the mod on them anyway.
I myself have a rule of only selling amateur euipment to licensed amateurs who can prove their qualifications. I wish is was law in all countries to do the same. Maybe then we wouldn't have unlicensed people on our bands.
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PA0FRI
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Rating: 5/5
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May 31, 2007 06:10
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Modifications
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Time owned: 0 to 3 months
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A Kenwood TL922 linear amplifier with 2 × 3-500Z valves is one of the best, sturdiest and compact build pieces of equipment for radio amateurs. It is equipped with double shielding in a cabinet of thick material with sturdy handles. It is designed with good quality components and there are separate transformers for the HV and filaments. If the HV transformer overheats a thermal safety device incorporated inside it will operate and disconnects the bias. When you switch off the amplifier, the cooling fan will carry on for a few more minutes. These are all features not present in a lot of current models. This is good advice if you come across a 2nd hand one , however there is always room for improvement.
A stable TL922 on 9 bands was the result after implementing modifications, like the length of the coax cable between exciter and amplifier, all grids direct to ground (no capacitors) and an extra earth wire to VC1. See:
http://www.xs4all.nl/~pa0fri/Lineairs/TL922/tl-922eng.htm
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G0PZA
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Rating: 5/5
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Dec 30, 2006 16:49
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Looks and feels Fantastic
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Time owned: 0 to 3 months
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Hi all,
Forgive me for cheating a little. I just acquired a BRAND NEW TL922 which is about 12 years old. Yes. Never used except on a dummy load. But It has some problems, and I need some parts which I cannot easily get in the uk:
The parts required for the linear are:
L7 470uH RF choke ( Fits from Grid to ground)
L8 470uH RF choke as L7
D2 Zener diode 7.5 Volts ( fits in cathode circuit to provide bias)
The manual does not give more detail than that. However looking at the circuit for the zener diode, it appears to dissipate about 5 Watts in normal use. That suggests a suitable replacement should be rated at double this. So 7.5V at 10W is probably the minimum specification for D2.
Can anyone help with any suggestions?
Best 73,
G0PZA, via QRZ.COM
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W8JN
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Rating: 5/5
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Dec 27, 2006 22:44
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Beautiful Artwork
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Time owned: more than 12 months
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This amp is a thing of beauty. Quite a sculpture ! Runs flawlessly and built like a tank. Tornados ripped through here last week and I tied the house to this beast and survived the wind! Mine is mint with factory box. Fantastic!
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AC7PN
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Rating: 5/5
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Sep 22, 2006 23:05
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Just retubed
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Time owned: more than 12 months
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My TL-922A had a 3-500ZG that started to arc internally so I ordered a new matched pair of Chinese (PRC) tubes from RF Parts. They are a bit expensive. It's back on the air tonight. I love the looks of this Kenwood unit. It really is a thing of beauty. I wish I had it running last weekend for the WA Salmon Run.
The old tubes were not a matched pair and I was hoping I'd get a little more power out with the new parts but I think its just about the same. My MFJ meter on the antenna tuner says about 900 Watts CW on 20 Meters. Who knows if it's correct? The plates get the same color of red so the matching must be pretty good.
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