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Reviews For: Ten-Tec Titan 425

Category: Amplifiers: RF Power - HF & HF+6M

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Review Summary For : Ten-Tec Titan 425
Reviews: 29MSRP: 3195.00
Description:
Full QSK, pair of 3CX800A7 tubes, 1500W output.
Product is in production
More Info: http://www.qsl.net/tentec/
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00294.8
AC5XP Rating: 2002-01-28
Well constructed amplifier, very good linearity Time Owned: more than 12 months.
I bought this amplifier in the early nineties, must have been one of the last ones they made. It is constructed well, and came standard with a high-speed Kilovac relay for full break-in, which I liked for AMTOR operation. Most competitors make you pay extra for that.
I tested the amplifier once with a dual-carrier input and a spectrum analalyzer on loan from my employer and could not believe my eyes: 3rd order product almost 40 dB down from PEP , 5th order virtually not visible any more, at 1700 watts into a military Bird dummy-load.
The concept of having the power supply in a separate case is actually nice, it allows for a relatively small box on the desk, not much bigger than my FT-990
The unit is easy to operate and is very forgiving against operator error. The internal fan is very quiet and actually has two speed positions.
The combination of two 3CX800A7 triodes in parallel (as this tuner uses) is probably the best for any HF amplifier. It offers excellent linearity at legal limit, and only loafs at 1500 watts full legal. Not much drive power is required and the two triodes seem to last quite a long time, although I had no opportunity to check this last statement (yet), see below.
Problem with this (and any) power amplifier is that such high power levels require good antennas, a good high-power tuner and a friendly neighbor. To start with the tuner, the Titan burned up my newly purchased MFJ-989Cin minutes. After I repaired that tuner (long story, see my 989C review) I had a continuing problem with a neighbor who owned a junk stereo and did not let me fix it on his side. That really took away the joy of using high power I must say. I haven't used the amplifier since, must have about an hour of milage on it because of that neighbor. So you have to realize that high power brings in a boat-load of problems you initially do not realize: My advice, if it works with 100 watts, stick to it.
But the amplifier is great, no question about that. Too bad TenTec came out with the cost-reduced version later which does not have the parallel 3CX800A7 tubes any more.
SM0FLY Rating: 2001-08-09
Excellent one ! Time Owned: more than 12 months.
Hi,
I got my 425 in 1988 and own it now for 13 years. It has been in operation since than almost every day at max legal power on CW & SSB. The only minor problems were:
1. After 1 week of operation in 1988, the grid current protection circuit failed. One of the transistors was blown ( probably not over dimensioned as it should be ). Replaced it with a heavier type and all worked fine since than.

2. After 10 years a small resistor in the power supply ( switch on surge delay circuit ) went down. A power/current calculation showed that the resistor was desigend at it's max power limit. Replaced it with a new one ( higher power rated ) and all ok .

Note:
I am not operating on 160 and never use QSK ( hate to hear my own echo's back on 20mtr!)
and I clean the 425&power_supply at least every year from excessive dust.

Summary :
One of the best tough amplifiers I ever owned!
/SM0FLY
AC5E Rating: 2001-07-14
EXCELLENT AFTER MUCH ABUSE Time Owned: more than 12 months.
I bought my 425 just after I got back into Amateur Radio in 1989. Since I have had mine twelve years, feeding antennas good, bad, and very indiffent, I figure I should be able to speak with at least some authority.
One of my first "additions" was an hour meter in the primary. The other was an AC voltmeter and a 5 KV DC meter on the front of the power supply. I probably voided the warranty - but I prefer full time grid current AND plate voltage monitoring.
Problems - two. The first was the rectifier stack that went south when lightning hit my power line as I was working the CQ160 contest. That was no fault of the design. I replaced the stock rectifiers with four units from Silicon Alley. No further problems.
The second was when a ceramic cap in the plate circuit went south. During another 160 Meter 'test - and while feeding an antenna that was far above 3:1 at the time. After some head scratching I figured out that the cap had almost 10 KV p-p on it. I replaced it with a 10 KV doorknob from Surplus Sales. And reworked my 160 antenna.
Other than that - no arcing. No burning. And no other problems in more than 6,000 hours of near full bore operation.
So I'm going to be in the market for another in the near future.
73 Pete Allen AC5E
N0FW Rating: 2001-07-14
Poor! Time Owned: more than 12 months.
Sure the amplifier works. But, since I have owned 2 from 1988 to 1995, let's look at facts.
First, the power supply. The problem with the first 20 editions were the diodes used in the
bridge rectifier. They were rated too small for the designed application. Ten-Tec's fix? Throw
more of them into each leg of the bridge. Next, the transformer. It was also rated too small
for the application. Ten-Tec's fix? Go with a Peter Dahl.
Now, to the RF deck. One surely has to question a designer who uses telephone hook-up wire
for board-to-board interconnects. Next, the loading capacitor. The original cap would arc when
high voltages were developed across the plates, especially on 160 meters. Ten-Tec's fix? Place pastic insulators in between each plate. This works for a time. Until you operate on 160 meters. Then the plates arc and now you have burned plastic and carbon to clean off.
This amplifier is better off on a display shelf than T an operating position!
W0DC Rating: 2001-07-14
Great Legal-Limit Amp! Time Owned: more than 12 months.
The Titan 425 is a classic legal-limit amp with excellent performance on 160 through 10 meters. The QSK works great with Omni VI's, FT-1000D's and FT-1000MP's. The 3CX800's last a long time! There's a simple upgrade available for the doorknob loading capacitor used on 160 that eliminates some tuning drift earlier units exhibit on that band. The separate power supply is a real plus.
K9OM Rating: 2001-05-13
Nice Amplifer! Time Owned: more than 12 months.
In addition to what has been posted above... I would like add the following comment: All of the Titan transformers seem to "hum" during transmit. This bothers me as I have had a Titan transformer die. High quality xformers usually do not "hum" during transmit. Many very small and compact amplifiers such as a Dentron MLA-2500 run close to the same power in a much smaller package... with no transformer "hum". I would like to see Ten-Tec use better transformers.
N8KR Rating: 2001-04-28
It's a Gem! Time Owned: more than 12 months.
With a pair of 3cx800's this amp loafs at 1500 watts. The external power supply can be placed out of the way on the floor leaving an attractice and fairly small and light weight "head" for the operating position. Full QSK works great. 10+ years of use and heavy contesting and it keeps putting out watts! Never a problem with good metering but . . . watch that grid current!
VE2DC Rating: 2001-01-25
As good as it gets with a manually tuned amp. Time Owned: more than 12 months.
160-10M including 17 and 12, but not 30.
Great vacuum relay QSK.
Great support from Ten Tec.
Compact. Mine is rack mounted.
Remote power supply means a wire in the shack carrying +2000V at high amperage... makes me a little nervous!
Tubes are expensive.
Capable of nearly twice the legal output, but would probably shorten tube life. Loafs at 1500W out.
K3BU Rating: 2000-06-06
Honey of an amplifier. Time Owned: more than 12 months.
I prefer to build and run my own amps especially in contests, but time comes for expeditions and Titan seem to fit the bill. Great workhorse for 160 - 10m, separate PS helps when transporting. No problem with contest duty perpetual CQing (installed fan inside of PS cabinet), works well with unstable AC line voltages (generators). I like the LED bar showing power, while meter sits on SWR monitoring possible antenna problems.
Problems? Some users experienced problems with vacuum relays (heavy QSK use?), padding caps in output PI network on 160 seem to drift a bit with temperature. Good protection features and metering.
Excellent amp, it can sit right on the front of you atop a rig, while PS is warming up the feet. Snatched another one when I saw it listed for good price.