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Tube Amp for 11 meters
- Thread starter SmackDown
- Start date
I'm studying for my tech right now, was at class last night when most of the replies came in. Didn't see a price chart at the Emtron site...("if you have to ask", etc., etc.)...but Doc said something about the 3-500 tube series which I didn't fully grasp. All I know is that I don't want to have to retube my Nitro at todays prices, it's like ordering lobster in any state besides Maine, it's going to cost you because the fluctuating prices and shrinking availability do not bode well. and yeah I kinda like ratchet jawing on the bowl and a few other channels where dx runs regularly, that's why the focus on 11 meter use...for now 
what's the difference between triode and tetrode ????? :?
73's
what's the difference between triode and tetrode ????? :?
73's
SmackDown said:
DI = two
TRI = three
TET= four
PENTA = five
Has to do with the number of elements in a tube envelope:
Diode only has cathode and plate.
Triode adds control grid between cathode and plate.
Tetrode adds screen grid between control grid and plate.
Pentode adds suppressor grid between screen and plate.
QRN said:datsun66 said:
You want a REAL kick? Try talking with 100 watts from Nova Scotia to Rodrigues Island via long path WHILE MOBILE. It's a mere 15,000 miles. Been there.Done that. Am ecstatic about it.
Kewl :rknrl long path QRN. 20m & 40m DX sure is fun especially with the 11/10m being pretty dead as of late.
I had a great time in the mobile on Sunday makin' left coast contacts in the CA QSO party. :CptnMorg As was stated earlier. Get the book(s) and study for and get your ticket. You won't regret it. Except maybe for the hole in your wallet which will only get bigger. :naughty Sorry for the post hijacking. At least if you get a high dollar amp that already has the other bands in it you can consider it an investment toward being able to use it QRO when you get the privledges to do so.
73's!
SmackDown said:
Beetle has it correct,more elements inside the tube. What it ultimately means is that the more elements inside the tube the lower the drive requirements are for the same power out. In other words,higher gain. A tetrode has higher gain than a triode and a pentode has higher gain than a tetrode.Tetrodes can have a power gain of 100 or more. The little 4CX250B which is a tetrode can provide over 250 watts output with just 1 or 2 watts of drive.You would be pretty hard pressed to find that kind of gain in a triode.This comes at the expense of more complicated circutry and involves at least one more power supply voltage for the screens.
When speaking of triodes vs. tetrodes the 3-500 series tubes are considered....????
and thanks for the good luck wishes on my tech exam. I'm ready for it now..I have a really good instructor.
3's
and thanks for the good luck wishes on my tech exam. I'm ready for it now..I have a really good instructor.
3's
With transmitting tubes, GENERALLY, the first digit indicates the number of elements: 3-500 = three elements = triode.
A 4CX1000 would be a tetrode (4 elements)...etc.
A 4CX1000 would be a tetrode (4 elements)...etc.
okay, NOW I understand what Doc meant when he mentioned that 3 of the 3-500 series tubes wouldn't do the kind of numbers I spoke of at first. Is there a way to change sweep tube technology to transmitting tube technology ? What needs changing, how intricate, feasibility ?????
73's
73's
Its a complete waste of money. The best bang for the buck is taking an old sweep tube amp and setting it up with 509/519 tubes. The tubes are cheap and plentiful......but still sweep tubes.
Master Chief said:
...but wouldn't that only be a lateral move ? Wouldn't that only do about the same output and still radiate harmonics and create TVI like the 6LQ6's do ?..You see I can get a D&A Phantom 500 but it needs tubes. Actually I have 2 to choose from. One has 3 settings, lo, med, hi and the other has only 2 settings, lo and hi. From what I've heard neither one can be driven by more than a radio...and they're trashy..
Between the Heathkit SB-220, the Pride DX300 and the Dentron MLA 2500B which of these 3 linears would develop more output if used on AM (11 meters)? Which of these linears can be driven with 100 > 150 watts ? I've read about SB-220's that had 4 tubes. Is that the normal configuration, 4 tube sockets in the SB-220 ? Does the Pride DX300 and Dentron MLA 2500B also have multiple tube sockets ? I'm looking to upgrade to a non sweeptube linear and these are the three I'm looking at.
3's
What the difference between the other tubes listed and a sweep tube? Besides gain of course.I have always had an interest in tube amps and wanted to learn so this is some great reading!
SmackDown,
Of the three I would guess that the MLA-2500B would offer the most output. But that's just a guess since it depends on a lot of things, and I am not familiar with the DX-300.
The SB-220 is a two tube amplifier, so is the MLA-2500B. The '220 uses two 3-500 tubes, the original '2500B used two 8875's. The 'problem' with the '2500B is that the 8875s are scarce, sort of. Both the '220 and '2500B are modifiable. What they can be modified into is just a matter of who'z doing the modification. Don't expect miracles from either. Do expect the modifications to cost dearly for AM use. The power claims are for input, not output power! Expect maybe 50% of the claimed power capabilities for output power, and lower for AM use. Buyer beware...
- 'Doc
Of the three I would guess that the MLA-2500B would offer the most output. But that's just a guess since it depends on a lot of things, and I am not familiar with the DX-300.
The SB-220 is a two tube amplifier, so is the MLA-2500B. The '220 uses two 3-500 tubes, the original '2500B used two 8875's. The 'problem' with the '2500B is that the 8875s are scarce, sort of. Both the '220 and '2500B are modifiable. What they can be modified into is just a matter of who'z doing the modification. Don't expect miracles from either. Do expect the modifications to cost dearly for AM use. The power claims are for input, not output power! Expect maybe 50% of the claimed power capabilities for output power, and lower for AM use. Buyer beware...
- 'Doc
You could get the Dentron and have have two 250B's installed. Don't know whats involved ( Know its more than just a tube swap ) in that but a friend has one that he has run that way for years. He is seeing around 2400 watts with a Galaxy 48T kicking it. The Pride DX-300 is a great amp and after a few changes to the power supply it will do 1100 watts but you cant drive it with anything more than a 20 watts.
What about a Wizard built base amp? I know he builds some big amps!
What about a Wizard built base amp? I know he builds some big amps!
SmackDown, if you do decide to go with the SB-220 on 11 meters you won't be unhappy. I'm very satisfied with the performance of my SB-220 on both AM and SB.