What output should I expect to see from a Heathkit SB-220 Tube Amp? It has two 3-500Z tube. What Average, and peak watts out should I expect, and what drive requirement on AM 11 meter band.
Thanks
Thanks
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Heathkit
- Thread starter Drifter
- Start date
Drifter,
If you don't already have one I would really, really suggest getting the manuals for the SB-220, both the operating manual and the construction manual. They save lots of time and expense in the long run. Another handy thing to know is that the Rich Major's web site (don't have the address, sorry) has all kinds of things for the '220 on it, mods that are worth doing and a few explanations that 'explain' things, sort of.
Something that's also good to know is that when the '220 was made the ratings for it were for -input- power, not output power. Big difference in what you can expect to see.
It's been much too long since I had one so won't try to answer anything specific. I do know that if a SB-220 isn't heavily modified, don't expect the often 'quoted' input/outputs. The power supply section is only adequate, not exceptional. It will never 'do' what other two 3-500 tube amplifiers can/will do unless the power section is rebuilt and probably moved 'out board'. They are very nice amplifiers if originally built competently.
- 'Doc
PS - If it's summer and you don't air condition your 'shack', you might want to invest in an air conditioner!
If you don't already have one I would really, really suggest getting the manuals for the SB-220, both the operating manual and the construction manual. They save lots of time and expense in the long run. Another handy thing to know is that the Rich Major's web site (don't have the address, sorry) has all kinds of things for the '220 on it, mods that are worth doing and a few explanations that 'explain' things, sort of.
Something that's also good to know is that when the '220 was made the ratings for it were for -input- power, not output power. Big difference in what you can expect to see.
It's been much too long since I had one so won't try to answer anything specific. I do know that if a SB-220 isn't heavily modified, don't expect the often 'quoted' input/outputs. The power supply section is only adequate, not exceptional. It will never 'do' what other two 3-500 tube amplifiers can/will do unless the power section is rebuilt and probably moved 'out board'. They are very nice amplifiers if originally built competently.
- 'Doc
PS - If it's summer and you don't air condition your 'shack', you might want to invest in an air conditioner!
Here is the link to Rich Measures website: Measures' Web Page
He has a large amount of info on the SB 220.
CBTricks has the operation and construction manual at: Heathkit SB-220
One thing to think about is if you are going to use the amp on AM it is a good idea to increase the bias voltage to the tubes. Rich has a great method for doing this which will cool the tubes down and let you drive it just a little harder if need be. Raising the bias voltage from the stock 5.7 volts to 8 or 9 volts will cool the tubes greatly. One good thing you can do is to place a 1 to 1 1/2 amp fuse in series with the zener diode (bias) to protect the rectifiers and other components in case of a tube or tuner arc. Cooling is a major issue on the SB 220 especially in the lower part of the chassis around the tube sockets.
Hopefully this info will get you started in the right direction.
BC
He has a large amount of info on the SB 220.
CBTricks has the operation and construction manual at: Heathkit SB-220
One thing to think about is if you are going to use the amp on AM it is a good idea to increase the bias voltage to the tubes. Rich has a great method for doing this which will cool the tubes down and let you drive it just a little harder if need be. Raising the bias voltage from the stock 5.7 volts to 8 or 9 volts will cool the tubes greatly. One good thing you can do is to place a 1 to 1 1/2 amp fuse in series with the zener diode (bias) to protect the rectifiers and other components in case of a tube or tuner arc. Cooling is a major issue on the SB 220 especially in the lower part of the chassis around the tube sockets.
Hopefully this info will get you started in the right direction.
BC
What is the high voltage reading on CW and SSB? Take the cover off and take a few photos and post them. Especially of the capacitors in the HV supply, the rectifier board, the bottom of the chassis, and of the tube compartment. Looking at this you can tell if any major mods or part replacements have done. There are some common things that go wrong on these amps and are good to do if they have not been already done.
One thing to remember is to be careful. The voltages in this amplifier will not hurt you....................they will KILL you!! Also the photos will tell if the interlock has been bypassed. Always unplug the amp and discharge the HV supply before getting too involved in it.
Above all ask questions if you are unsure. There is no such thing as a stupid question....only stupid mistakes.
Good luck with the amp.
BC
One thing to remember is to be careful. The voltages in this amplifier will not hurt you....................they will KILL you!! Also the photos will tell if the interlock has been bypassed. Always unplug the amp and discharge the HV supply before getting too involved in it.
Above all ask questions if you are unsure. There is no such thing as a stupid question....only stupid mistakes.
Good luck with the amp.
BC
- No one is chatting at the moment.
