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Henry Tempo 2000 General info and upgrades,
- Thread starter cbkidd1
- Start date
BJ radionut
Supporting Member and 6m addict
Uses (now) hard to find 3-400 tubes but chassis mounted tube sockets can be modified to fit the 3-500 instead.
eHam.net
HENRY RADIO TEMPO 2000 USER MANUAL Pdf Download | ManualsLib
Also NO tuned input circuits...
Also pay close attention to manual as the spec ratings are list as INPUT.
So 2000 watts PEP is INPUT rating not Output..
CW/AM rating is 1000 watts input max drive on low voltage 55 watts PEP ...etc...
They were very well built, but different ratings were used in those days, so when they say 2000 Watts PEP SSB rating...
EX: 2000 x .60 (efficiency) = 1200 watts output +/-
CW/AM :1000 watts x 60% = 600 watts PEP output +/-
Even if mod done for 3-500zg's...output pretty much same as SB220 or Drake L4B when operated on 240 volts...
My 2 cents worth
Enjoy
All the Best
Gary
eHam.net
HENRY RADIO TEMPO 2000 USER MANUAL Pdf Download | ManualsLib
Also NO tuned input circuits...
Also pay close attention to manual as the spec ratings are list as INPUT.
So 2000 watts PEP is INPUT rating not Output..
CW/AM rating is 1000 watts input max drive on low voltage 55 watts PEP ...etc...
They were very well built, but different ratings were used in those days, so when they say 2000 Watts PEP SSB rating...
EX: 2000 x .60 (efficiency) = 1200 watts output +/-
CW/AM :1000 watts x 60% = 600 watts PEP output +/-
Even if mod done for 3-500zg's...output pretty much same as SB220 or Drake L4B when operated on 240 volts...
My 2 cents worth
Enjoy
All the Best
Gary
Another mid-1960s 3-400 amplifier meant to use with radios that had tube-type final stages. The 3-500 replaced the -400 in 1970, pretty sure. It's taller, so you have to drop the tube sockets a bit to provide overhead clearance.
The complete lack of a tuned input means that the Load and Tune controls on the radio will peak differently driving the amplifier than driving an antenna. There are other drawbacks to this "untuned input" design, but we'll skip those for now. A modern solid-state HF transceiver will reduce power or shut down altogether trying to drive this amplifier.
If this was the radio equivalent of a Jaguar "E" or a late 60's 'Vette you could make a case for updating it to use again. But the Tempo 2000 is more like a 4-cylinder short bed pickup from 1965.
The Tempo won't have a rusted-out bed, but being sure the big, expensive transformer is okay would be wise just the same.
I ended up the accidental owner of one of these. Never have talked myself into rehabbing it.
73
The complete lack of a tuned input means that the Load and Tune controls on the radio will peak differently driving the amplifier than driving an antenna. There are other drawbacks to this "untuned input" design, but we'll skip those for now. A modern solid-state HF transceiver will reduce power or shut down altogether trying to drive this amplifier.
If this was the radio equivalent of a Jaguar "E" or a late 60's 'Vette you could make a case for updating it to use again. But the Tempo 2000 is more like a 4-cylinder short bed pickup from 1965.
The Tempo won't have a rusted-out bed, but being sure the big, expensive transformer is okay would be wise just the same.
I ended up the accidental owner of one of these. Never have talked myself into rehabbing it.
73
Evening BJ and Nomad,
Nice to hear from you guys, The tempo has had the 3-500z tubes put in place. I was told the tubes might be weak that are in it. Was told it only keys about 400 with the current tubes. Runs about 1700 volts on the low tap, and about 2300 on the high tap. Kind of got me wondering about the transformer after what Chris had just said? Here are a few pic's, After reading back over the output numbers only to see 600 watts output on AM is kind of disappointing.
Nice to hear from you guys, The tempo has had the 3-500z tubes put in place. I was told the tubes might be weak that are in it. Was told it only keys about 400 with the current tubes. Runs about 1700 volts on the low tap, and about 2300 on the high tap. Kind of got me wondering about the transformer after what Chris had just said? Here are a few pic's, After reading back over the output numbers only to see 600 watts output on AM is kind of disappointing.
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Unless it was modified, this is a true zero-bias amplifier. Holding the HV down to those levels serves to reduce the zero-signal "idle" current, and the heat that it generates. It's still a sideband/CW amplifier. To use it for AM I would put 15 or so Volts of bias in the cathode return. You could use a monster zener diode, or a series string of 20 or so rectifier diodes in series. Performance will tend to be disappointing with the untuned input. Seems to be worse on the highest band.
Installing a way to switch the correct tuned-input circuit in line for each band will be mechanically clumsy in one or more ways.
73
Installing a way to switch the correct tuned-input circuit in line for each band will be mechanically clumsy in one or more ways.
73
Chris, I Just wanted you to know. I have always listened to what you have to say. Anytime I have had a problem with any radio gear. And you have also taught me quite a bite. I very much appreciate everything, Is there anywhere I could find the info on what size rectifier diodes I would need and a diagram showing me where to place them? That way a dummy like me won't screw it up. I really would appreciate it. Thank you again for all your help, It sure would be nice to have all the problems Taking care of before putting the tempo into service,
My go-to rectifier for this size amplifier has been the 1N5408. It's rated at 3 Amps and 1000 Volts.
It's a fairly generic part, Fleabay, Mouser, lots of other sources.
73
It's a fairly generic part, Fleabay, Mouser, lots of other sources.
73
I had genuinely forgotten what a wacky specimen this amplifier really is. You have to have the power applied to it, even when it's turned off. It was meant to use with a separate receiver and transmitter. It serves as the "Dow-Key" relay that switches the antenna from your receiver to the transmitter when you key it.
But only when it's plugged in.
Here's the backwards part, from the manual:
Not your normal setup. You can't receive through it without that hookup. And keying it is done by opening the keying connection circuit, and closing it to receive.
Like I said, wacky.
As to where you would put bias diodes, I should see if we have any pics of the last one we saw on file. Not a lot of spare room in this one.
73
But only when it's plugged in.
Here's the backwards part, from the manual:
Not your normal setup. You can't receive through it without that hookup. And keying it is done by opening the keying connection circuit, and closing it to receive.
Like I said, wacky.
As to where you would put bias diodes, I should see if we have any pics of the last one we saw on file. Not a lot of spare room in this one.
73