Tube Linear Amplifier always Tune and Load for Max
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- Опубліковано 20 сер 2024
- On any Tube Linear Amplifier with a Tune and Load on the output, always tune for max output except you can over couple the load down a little maybe 3, not 10% or 50% as I hear some talk about. When you tune an amp for less output, the watts that you tuned down stay in the tube instead of going out to your antenna. Simply put, your tube(s) eat those watts. If your amp has a Volt and Plate current meter, the watts your tube is seeing is the voltage times the plate current, but minus the watts the amp is putting out. Say you got an amp with 2kv voltage at 1 amp current thats 2000 watts. If the amp is doing 1000 watts out then the tube is eating the other 1000 watts. This is normal. Amps run at 50-60% efficiency. However if you tune down or detune the amp to 500 watts out, that 2000 watts - 500 watts so the tubes are now eating 1500 watts. It drives me crazy when operators say I tune mine down so it will last a long time. I tune my 1000 watt amp down to 250 watts. There are many bad things you can do to an amp. Over drive it, high SWR, Hot Key the keying relay, but not tuning for max is 0ne of the worst, IMHO
Y'all need to listen to this man. If you want to do less watts on amp and save tubes, turn wattage going in down.
This man knows his stuff!
So true and yet so many hate the 'Dial a watt' thing.
I ran several amplifiers over the years, mostly with 6lq6 tubes or the like.
I ALWAYS ALWAYS ALWAYS tuned for max smoke. All I did was adjust the drive wattage going into the Amp to vary output on the amp. Worked a treat, and NEVER had to replace a single tube.
That is the only way to do it.
@@tramdr Amen.
Happy New Year!!
You could not be more right about tuning for maximum output!!!!! I found out the hard way lol.
I love your videos!
117 thumb of Michigan. 73’s
Bare Footing the Big Box ! Pearls of wisdom , well done ! thanks n Happy new year !
Wise words,my friend."trying to enlighten fools is having a battle of wits with an unarmed opponent".…
I was working on a big power supply that had been turned off for a long time.....I took a big screw driver and laid it across the big cap...snap.....it practically welded the screwdriver.......those big caps can hold a big charge for a long time.🔌
A very long time ago, I was working on a video game at the Greyhound Bus station. It had been off for months. I got bit by the HV off the monitor. I screamed out. Nobody paid me any attention LOL.
@@tramdr did you get hurt....any residual effects?
@@nordland2235 Naw, I wasn't hurt. Might have had the effect of a light Taser. Zap, then that's it. I screamed out like a girl for 2 seconds. Thought everyone would be looking and laughing at me, but nobody paid me any attention.
All good information, thank you.
Happy New Year.
That Alpha is a nice box sir ! Thanks and 73s
Lovely amplifier!
Very informative. Am planning to get amplifier for my icom and wasn't sure how to tune it if I didn't want to run it full output. Thanks
does your Icom have variable?
Thank you No.Name....Very infotmitive. saving info to live longer and key stronger. thank you...73...033 bump bump
Boom!
Very informative, I could have boughten this amp from a guy in Ontario but it has problems. I found a super clean unused pride dx300. I kind of wish I had of bought this one now lol.
Rock on!
You should start a patreon for teaching. Id join in a heartbeat
"Always tune and load for max..." Yeah, unless it's an AL-811h like the one I purchased: Went into a failure mode when it's driven past 50% of rated power, right out of the box... Sent back for warranty repairs & still has the same issue after it was returned.
"when it's driven past 50% of rated power".......Hmmmm. I have nothing to say on that.
Thanks for sharing.
Nice amp ... love to have that
Well done,
Thanks
Very interesting .....I have a Box with 1 single 3-500Z tube and I tune using RTTY for the exciter and I start with 10W just happens to be the Minimum the Yaesu Rig will do and then a second time with 25 Watts RTTY and Tune Plate & Load for Max Power .....after the Tune switch to SSB and that is were I mostly operate for a Super Clean Powerful Signal ....73
I agree with starting with lower drive and also on the low side of an amp to start tuneup (saves the tubes) but with my last adjustments, I tune for maximum modulating watts, not max dead key watts, then over-couple it a couple watts down.
Tell em Doc ! Folks will never learn
Thanks, I'll try.
One question my brother, why the heck would you even attempt working on this type of equipment in your bare feet??? I think this is a true example to your viewers of what you SHOULD NOT BE DOING. Love the tutorials just be careful.
Thanks.
Isn't working around electrical "stuff" barefoot kind of hazardous?
I think the same as touching stuff with your bare hands.
Hey TramDr.. if I wanted to drive a 3cx3000 with a sweeptube amp do I need to do something special? I heard I have to marry them..
Nope.
Are you sure you didn't mean:
Always tune for the maximum peak MODULATED output power?
Because when you modulate and see that plate current rise, the PLATE CIRCUIT IMPEDANCE changes; (decreases), requiring you to slightly readjust the tuning for your maximum peak power output at that new operating point.
If you always tune for maximum peak output without modulation, you will be tuned for maximum average power output on a dead key, but would not be tuned for maximum peak power output when modulated!
I'm sure that's probably what you were trying to say; and just clarifying it for everyone else to understand.....
Dennis O. #12
I agree and tune for max peak on AM, but many do not. Some peak for max dead key and others key for RMS using average audio power, not peak, meaning saying something like AAAhhhdddiiioooo vs a whistle. I did not want to get in that debate here, so I simply say always Tune for max. Here, I don't want to get into plate current dip, plate impedance, overcoupling, peak watts vs rms, etc. Heck, very few CB amps even have a plate meter. If I can convince those that detune an amp to not detune it, I'm happy.
KV=Kill Anyone Volts
Agreed.
12:09 I wonder what was going on there? it was sucking alot of plate amps with no modulation and creeping up.
Was a blackcat going into oscillation?
actually I noticed that too when making the video but didn't want to stop or remake the vid. So after I posted the vid, I went back to try to see what was happening. I found that after about 5 minutes, the variable -bias circuit I put in the JB-76 starting drifting down, causing the JB-76 to take off. I have not tried to fix this yet, as normally I don't talk that long anyway. Unkey for 5 secs and it goes back to normal. Hmmmm.
Where is that amp today?
Sold it to a local years ago and he loves it. It was some growing pains when I first sold it to him though. First of all, 2kw and above amps just will not run right on a normal house 110 line. 2nd, most operators stations cannot handle 2kw plus. There is more, but I will stop there. To this day, I am hesitant to sell a legal limit+ amp to anyone as most are not ready.
How long can you key that amp down without hurting it?
Are you really asking me that question about an Alpha? Really? My answer is if ran right, about 8 years, then change the tube and then key for another 8 years. Fact, Alpha used to go to 3 day swaps and literally put a brick on the footpedal and key it down on a dummy load with full power out for the duration of the swap. Another fact, some broadcast AM radio stations used alpha's as drivers, keyed down 24-7. Henry and Alpha are the 2 amp makers that I know of whose amps where used for radio station drivers, and also used in the medical field, radiothermy.
@@tramdrCool.....helluva linear......I was just wondering........I have heard some of those guys on the super bowl keying down for a long time.