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HEATHKIT SB 221
- Thread starter hank
- Start date
Average drive is something between 40 and 100 watts. Anything over about 100 watts is asking for trouble. Typical output power is in the neighborhood of about 1000 watts. I'd consider that the top end if you want it to last for any length of time.
All of the HeathKit amplifiers were sort of power supply handicapped, just not the strongest in the world. Also, it's ratings were given for input power levels NOT output power levels. Don't expect anything like 2000 watts unless you do some -very- extensive modifying. AM, maybe 300 - 500 watts at best (which means with a reasonable tube life).
Absolute best advice is to get both the operating manual and the construction manual. Then READ them! Second best advice is don't push it without a spare set of tubes handy, wouldn't advise it then either, but it's your wallet.
- 'Doc
All of the HeathKit amplifiers were sort of power supply handicapped, just not the strongest in the world. Also, it's ratings were given for input power levels NOT output power levels. Don't expect anything like 2000 watts unless you do some -very- extensive modifying. AM, maybe 300 - 500 watts at best (which means with a reasonable tube life).
Absolute best advice is to get both the operating manual and the construction manual. Then READ them! Second best advice is don't push it without a spare set of tubes handy, wouldn't advise it then either, but it's your wallet.
- 'Doc
Holy $h!+skis!!!! 900 in!!!! What mods were done to that thing and 2800 out please tell what has been done and where you sent it? And what tubes your running what Voltage are you running this on 110V 220V??? and I wanted a simple 1000-1500 watt in trade for this new Texas Star 1600 I have for trade maybe Ill sell it and find a 221
I am with Tony.
I like to know this also.
And please detail us on the bias and input circuit.
As Doc noted the supply can hardly handle the legal 1500 on ssb.
I have seen some modified with seperate supplies and an extra tube added that want to this.
If you bastardize your drive waveform enough so it looks like a radar pulse any 2000 DC input amplifier can be made to show 3000 watts on a Bird meter.
Will it be heard any better than the normal 1200 watts out. No except for when you tune off channel.
YAHOO!
Will it be heard any better than the normal 1200 watts out. No except for when you tune off channel.
YAHOO!
TRUE STORY!!!!^^^
I laugh when I see guys cry after putting a good low pass filter on there out put and show them what they are really producing. Then when they argue and say the filter is killing there signal I tell them to go home and ask if there signal dropped on anyone with the filter in or out of line. 9 times out of 10 It doesnt! Harmonic power does not equal power density. Just because you are txing high power on a VERY broad bandwidth doesnt mean there is any more power being applied to the target frequency. Clean signals will always win hands down!!
Back to the SB221. There is no way 2 3-500z's are taking that abuse unless the input is padded to the point of being anemic.
The amplifier is also VERY ineffcient ( 900 in ----2800 out = about 5db gain)
Original( 100 in -----1200 out= about 11db gain)
They converted the amp into a space heater hahaha
900w PEP input is just absolutely insane....
op:
ive used my SB-220 for yrs with a 2pill mobile amp as a driver...on my bird43(NO PEP KIT) i run 250w carrier & forward modulation is around 750w-800w....i have a diawa 101-CL but its pegs out on the 1500w scale on PEP mode, avg mode reads the same ouput as the bird43...
chastise me and criticize me all you want, but ive ran like this for yrs with no issues...
op:ive used my SB-220 for yrs with a 2pill mobile amp as a driver...on my bird43(NO PEP KIT) i run 250w carrier & forward modulation is around 750w-800w....i have a diawa 101-CL but its pegs out on the 1500w scale on PEP mode, avg mode reads the same ouput as the bird43...
chastise me and criticize me all you want, but ive ran like this for yrs with no issues...
900w PEP input is just absolutely insane....
ive used my SB-220 for yrs with a 2pill mobile amp as a driver...on my bird43(NO PEP KIT) i run 250w carrier & forward modulation is around 750w-800w....i have a diawa 101-CL but its pegs out on the 1500w scale on PEP mode, avg mode reads the same ouput as the bird43...
chastise me and criticize me all you want, but ive ran like this for yrs with no issues...
You said your PEP meter was showing around 1500PEAK, thats about normal on a driven SB220, thats where the PS usually craps out.
The other guy said he ran 900 peak. Thats is insane Whats your 2 pill doing???? Maybe 250 peak. Thats still pushing it, But ALOT better than 900.
We have a moron around here that used to brag about driving his L4B with 300 and how it was SCREAMING at 2300watts........That was until he keyed up one day and filled the room with smoke haha One of the local GOOD amp builders looked at the box and called him a dumbass to his face and offered him $100 for it or he would repair it for $700
People need to learn that pushing equipment does nothing but harm the equipment.
I could let my Titan 425 to cruise at 2400 with 90 watts drive or run upto 150 watts into it and get 3500 watts out. But that 1.5 db gain isnt noticeable AT ALL on the other end and Im just abuseing my equipment.
first things first, im not long winded when TXing and that is key to longevity, the stock transformer is certainly not designed for that especially when using AM....
the 2x1446 amp is not doing anywhere near 250w PEP...more like 190 at most(astron vs-70 @15v, drawing like 12 amps) but i'll have to double check...just a tad under 2w in nets me a 25w or so carrier, radio is a uniden 78XL doing about 7-8w on the bird 43...
im not going to get into the IMD/harmonics & hammy/ssb VS dumb CBer on AM pissing match....ive had this same set-up for 7 yrs now with no issues(78xl/2pill/sb-220/I-10K), everybody seems pretty impressed with audio clarity and signal locally and in DX, but its not hard to plz dumb CBers...it doesnt sound as bad as you may think, granted its just simple stuff and ITS NOT flex injected pro audio from a PC progra/studio equalizer stack...lol
but i certainly know what you mean...i have a local that swear his 9x8950 sweep tube amp does 1700---1800 hundred on low supposedly...and he drives it with 200w from a hacked up and clipped galaxy and sounds very very over modulated with a constant snap crackle pop effect that totally diminishes audio clarity....lets just say him and his cb shop tuned dosy are not very bright...
LMAO I may have heard this guy on is he an older guy?? I heard a guy lastweek that was doing what you explained on the audio side of things!!! Anyways there is always going to be different opinions on these things and most of all WHAT WORKS FOR ONE GUY MAY NOT WORK FOR THE NEXT GUY.
I just cant understand some of the output specs people share or talk about that there setup is doing but hell look most of the compotition amp builders and what there claims are. I mean even after doing the math it just cannot work to acheive there power ratings and there specs or claims.
I always tell people give me a few minutes with any of my several meters and I can have RCI 2970 putting out 400 watts!! If you see what Im getting at
I just cant understand some of the output specs people share or talk about that there setup is doing but hell look most of the compotition amp builders and what there claims are. I mean even after doing the math it just cannot work to acheive there power ratings and there specs or claims.
I always tell people give me a few minutes with any of my several meters and I can have RCI 2970 putting out 400 watts!! If you see what Im getting at
With all of the HeathKit amplifiers I'm familiar with there are meters that will tell you what the thing is doing. (That assumes that those meters haven't been 'fiddled' with and they still work.) They can tell you quite a bit about things if you know what they are telling you.
All of the heathKits were 'desk top' amplifiers, meaning that they were never the huge power producing things most people think they were. The main reason none of them did the absolute maximum power thingy was because the power supplies were not capable of supporting that sort of thing. There are gobs of mods that do help them, they range from filament voltage reduction to increase tube life, to huge transformers.
Something to remember is that all the power claims were in terms of input power, not output power, big difference. I think the last model or two may have been rated differently, not sure.
Depending on the mode, there's a fairly wide range of drive power levels. With a 3-500 of any type, 900 watts of input power means very large power amplification for VERY short periods of time. That 'time' is measured in seconds, and there's no second chances granted. It does mean a 'ruptured' tube, as in Christmas tree ornament. And that's with a very heavily modified amplifier, not a stock one. It also means a total revamp of the cooling system, forget a fan, won't even get close to the air movement required and that's with the tube enclosures. There will still be enough heat produced that I hope you have ceramic tube sockets and used silver solder on the pins.
I don't care who makes these silly claims, CB'ers, hams, whoever. They are still silly (to put it nicely). If you want that kind of power forget a 3-500 tube I don't care how many you use. It's just not very practical. Two 3-500s for 2500 watts out on AM? You bet! My Chevy truck get's 75 miles per gallon too...
- 'Doc
All of the heathKits were 'desk top' amplifiers, meaning that they were never the huge power producing things most people think they were. The main reason none of them did the absolute maximum power thingy was because the power supplies were not capable of supporting that sort of thing. There are gobs of mods that do help them, they range from filament voltage reduction to increase tube life, to huge transformers.
Something to remember is that all the power claims were in terms of input power, not output power, big difference. I think the last model or two may have been rated differently, not sure.
Depending on the mode, there's a fairly wide range of drive power levels. With a 3-500 of any type, 900 watts of input power means very large power amplification for VERY short periods of time. That 'time' is measured in seconds, and there's no second chances granted. It does mean a 'ruptured' tube, as in Christmas tree ornament. And that's with a very heavily modified amplifier, not a stock one. It also means a total revamp of the cooling system, forget a fan, won't even get close to the air movement required and that's with the tube enclosures. There will still be enough heat produced that I hope you have ceramic tube sockets and used silver solder on the pins.
I don't care who makes these silly claims, CB'ers, hams, whoever. They are still silly (to put it nicely). If you want that kind of power forget a 3-500 tube I don't care how many you use. It's just not very practical. Two 3-500s for 2500 watts out on AM? You bet! My Chevy truck get's 75 miles per gallon too...
- 'Doc
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