In the picture below, the amp is shown along side of my father's (VE1JNA - SK) Kenwood TS-850SAT, and these do make a nice pair.
|Kenwood TS-850SAT and TL-922A|
The TL-922A is a heavy brute coming in at 31kg. Flipping this beast over, when working on it will leave marks on your desk if you are not careful!
The HV supply has two modes which change the plate voltage from 2.2kV to 3.1kV for CW and SSB modes. In SSB mode this amp is specified to generate 1kW out for approximately 80W in. (This is what the curves at the back of the service manual say!)
Call me old fashioned, but if you are like me, then you too believe radios must have plenty of knobs and switches to be interesting. I should add that the metering on the TL-922A also meets my expectations too. I know analogue meters miss the peaks but there is a satisfaction in seeing the physical needle move as you tune up the amp.
Many folks have commented on the physical build quality of this design, and I will add my comments to the pile-up. I did not confirm when this unit was built, but being of the late 1970's, I can say this 30 year old unit will be here for many years to come because it does not show its age. I was very lucky because the previous owners, and I do not know how many there were, have taken good care of this amp.
I have picked over much of this amp from outside and in, and in terms of modifications, there are only a few.
- The Tubes are a pair of 3-500Z's from the good folks at RF Parts.
- The suppressors are the original Kenwood items and have not been changed out.
- The 10M band addition was done as described here.
- The HV caps have been replaced with Cornell-Dubilier 210uF 450VDC
- The SS-100 Universal Soft-Start from Harbach was installed
|Burnt Plate Cap?|
|Installed Multi Tech Band switch|
|Shorted input filter for 20m|
As an example, operating on 40m, the setup below shows 55W in and 650W out. The plate and grid currents are 450mA and 150mA.
|55W in and 650W out|
Having only had the amp for a few weeks, I know this is going to be a good addition to the shack. If you are in the market for a this piece of Kenwood history, I hope you are able to find an Amp as well cared for as I was able to.
MHz 1.8 3.5 7 14 21 28
Band 160m 80m 40m 20m 15m 10m
Plate 3.5 7 7 14 21 >21
Load 0 1.8 2.2 4 4.2 4.8
Ip (dip) Yes Yes Yes Yes Yes Yes
Ip 480 500 500 500 500 350 (mA)
Ig 200 150 180 175 150 150 (mA)
HV 1900V 1900V 1900V 1900V 1900V 1900V at load
Pout 550 600 700 800 625 435 (W)
Pin 65 55 75 70 55 40 (W)
SWRin 1.5:1 1:1 1.3:1 1:1 1.3:1 2:1