Discussion in 'Amateur Radio Amplifiers' started by WA6MHZ, Jul 31, 2017.
I don't think you will need shielded wire.
I like that relay board, looks nice.
Today the 10A circuit breakers came in, so tomorrow morning marks my TOTAL CAPITULATION to the EXTREME DURESS I have Received in this thread.
I WILL Install the breakers, regardless of whether I agree with it or not.
I have had all these NUMBERS thrown at me, showing the maximum current COULD REACH around 9AMPS, which would pass through a 10A breaker. Maybe. Maybe it will, or maybe it will trip. So I am going to instruct my friend to be ready to pull the SB-220 out from the shelf and reset the breaker, and then try again, at a lower power level. He is going to be upset he is not getting the MAXIMUM power out, but I have to tell him it was just DESIGNED VERY POORLY!!!
As an Electronics Technician for nearly 50 years, I have more than seen my share of poor designs.
I remember one run of boxes this So called GENIUS of an Engineer designed that had to be completely scrapped when I proved to him there was NO WAY IT COULD HAVE EVER WORKED!!!!
Thousands of dollars were squandered because he went right from Paper to the PCB and Designed it HIS WAY. He was WRONG and had to eat crow because some miserable $4 an hour lowly Technician proved that all his book learning and Degrees did NO GOOD when it comes to actual operation.
So the SB-220 transformer is evidently VERY FRAGILE, not able to even supply the required current it is speced for. I saw the same thing with the DX-35 and DX-40 transformers, and as Dave UUU found, with the DX-20 as well. They cook out way too easily.
Even at the RAdio Hospital, the Genius Engineering team designed a High Def video receiver that NEVER WORKED!!! All they shipped out have come back, and they can't fix them!!! All kinds of customers that bit on the bait and spent Tens of THOUSANDS of Dollars on these junkers are burnt!!!
They can't be fixed, cuz they never worked to begin with, or if so, just barely.
So Heathkit Engineers are long praised for their GLORIOUS DESIGN, while in fact it is a Faulty design that is too delicate to push past the precarious limit.
Meanwhile, I violate ALL THE RULES with my DRAKE L7, which is BULLETPROOF!!!
I Run it on 120VAC, run RTTY in the SSB Mode, and peak it for Maximum output in all cases. I tune it up into antennas no where near resonant (Like a Cushcrud R7 on 160Meters) and just let it burn the RF into the atmosphere. Because, Making the CONTACT is what the whole point is. The AMP is Expendable!!! If it burns up, it burnt up. But I made the QSO which is the whole point of even running the AMP!
I am completely involved in DXing, and I need EVERY MILLIWATT I can muster. My station is like a KAMIKAZE!!! If I blow it up and I make the QSO, it was worth the effort!!!
So now Sue informs me that I can't peak the SB-220 for maximum, I have to back the load and power way off to protect the very delicate Innards. I need to PUNCH AS HARD AS I CAN when calling a DX or I will not be in the log. That is why I don't believe in QRP!!! THE ONE WITH THE MOSTEST IS THE ONE WHO GETS IN THE LOG!!!
That is the WHOLE POINT of amplifiers. Yes, some East Coast stations have worked all their DXCC countries on 100W, Congratulations. But out here in California, it ain't that easy. If you ain't got a BIG AMP, you ain't getting in the log, unless U are incredibly lucky!
So I have CAVED IN and early tomorrow morning, I will TEAR OUT the 15A breakers and install the 10A wired according to the circuit. REGARDLESS of whether I agree with it or not.
There was a Really good movie I just watched called "ALLIED"
It was set in WW2 and Brad Pitt married a beautiful girl he met in Morroco.
They married, moved back to England and had a daughter together.
Then the Military command discovered she was really a German SPY sending back
critical data to the Nazis!!!!
Brad Pit was ordered to KILL HER
well I won't go into what happened in the rest of the movie, but I feel just like BRAD
in this plot here.
I have been ORDERED TO KILL this SB-220, that I have worked SO HARD ON and poured so much love into.
OK it is going to die! I HAVE TO OBEY ORDERS!!!
Based on the power limit at the time of manufacture (1 kW DC or 2kW PEP INPUT), and the lower duty cycle of SSB & CW (about 25/33%), it gets by with 600VA. If you want more, there are alternatives.
So, you're saying you know more than the designers of the SB-220? Really???
I only said you had to
1. Add some loading by advancing the load control until you see a 5% drop in power. That is what 20W..
2. I was also cuncerned with driving the amp with more than 100W with the damaged tune cap installed.
As far as the transformer that one doesn't belong to you so I would treat it with kid gloves.
(notice I wasn't urging caution with the SB-226 power supply)
All is good...
I am just saying the transformer is the ACHILLES HEEL of the SB-220!!!
You are up awfully late...
I am also..
Watching Deadliest Catch..
I told you that. Many others before us have stated the same. That's why P.W. Dahl has replacements that can supply more.
You also said it was "DESIGNED VERY POORLY" and is a "faulty design". That says you think you could've done a better design. However, many big brains say the SB-220 HV power supply was sufficient for its time. I believe them, not you, Pat.
What I would have done is design it so it would LOAF along at full power output. I think the Tuning Capacitor is way suspect too. The plates are too close together. Heathkit's goal was to make it in an all in one compact package. I think Drake's idea of a seperate power supply is a far better design in the L7. Which is why I designed the SB-226/HP-226 with the remote power supply. with a remote PS, you can have a much heavier duty power transformer and it won't take up space or add considerable weight to the Amp itself. SO, yes, I COULD have designed it better and DID design it better with my version.
But the big consideration is COST. Heathkit wanted to make it affordable. Earlier designs such as the Chippewa were much more Robust and had a separate supply
here is the KS-1 remote PS. TALK ABOUT IRON!!! You must have had to use a FORK LIFT to move this thing!!!
But the Chippewa was a Flawed design too due to the Plate meter being lit up at full HIGH VOLTAGE, so it was quickly discontinued and few exist left in the world!!!
Ruggedly constructed for heavy-duty use in medium to high power installations, the KS-1 fills the requirements of a top-notch power supply with ecomony and safety. Features an oil-filled hermetically sealed plate transformer, "potted" swinging choke input filter and 60-second time delay relay. Line filters minimize RF radiation. Maximum DC power output is 1500 watts. Nominal voltage output, 3000 or 15000 volts. DC current output, average 500 ma, maximum 1000 ma. COntrol circuitry is arranged to allow remote installation. The KS-1 employs two 866A half-wave mercury vapor rectifiers in a full-wave, single-phase configuration. Power requirements: 115V, 50/60 cycles, 20 amperes; 230V, 50/60 cycles, 10 amperes. 105 lbs."
They didn't care that the KS-1 was heavy, because it was to sit under the table.
The SB-220 was an all in one, table top package like the SB-200. I can just barely lift the SB-220, but I can! I move it from the cart to the desk every time I work on it. Will do that in a few minutes. I will remove the tubes as it is time to start on the QSK mod procedure. ( I am still waiting on the MOUSER PARTS for the W7RY board)
The SB-220 is rated to weigh 48 Pounds. I didn't weigh the HP-226, but I would guess it weighs nearly that. The SB-226 probably weighed 15 pounds. Sue lifted it to a high shelf.
The SB-220 was listed at $350 in the 60s.
So the key focus was to make it as CHEAP as possible. AND ALL in one.
So yes, it is a FLAWED design, which is why mine is better!
That was sixty years ago...
This is Now
If that is too much for you, maybe something a little more pedestrian will fill your needs.