I just bought a couple of 811a tubes to start to experiment/build an amp. I also bought a 15th edition and a 22nd edition of bill orr's Radio handbook. Also bought RCA's TT-5 transmitting tube book. Any ideas or suggestions on what I might need or that may help me better understand tubes would be great. Got a really great deal on a pair of 4cx350A tubes as well ( I paid $30 for the pair) but the 811a's are the first leap/project.
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Tube amp help
- Thread starter Crusher
- Start date
I'm sorry, but if you have no experience with building electronics, I'd advise not going any further. There really is a fair amount of 'stuff' you should know, and picking it up off the internet isn't exactly the best way to go about it. And that says nothing about safety, as in the voltages required for those 811's can convert you to a 'dearly departed' very quickly.
I may be misreading your post and if so, sorry again.
- 'Doc
I may be misreading your post and if so, sorry again.
- 'Doc
LOL, uh, W5LZ, um, do you not recognize the handle? LOL
crusher builds his own amps, and in my opinion is pretty educated on the subject. he has been around here for a while.
my guess is that he is asking for some "tips and tricks" from the guys who have more experience with tubes.
as far as i know he only works with solid state stuff so far.
anyway, hey crusher, long time to type.
hows things? any cool projects going on at the moment besides the tube amp?
later,
LC
crusher builds his own amps, and in my opinion is pretty educated on the subject. he has been around here for a while.
my guess is that he is asking for some "tips and tricks" from the guys who have more experience with tubes.
as far as i know he only works with solid state stuff so far.
anyway, hey crusher, long time to type.
hows things? any cool projects going on at the moment besides the tube amp?
later,
LC
There is a big..........no, wait a minute.......HUGE differance in building solidstate amps versus tube amps. One can have all the knowledge in the world about solidstate amps and projects and still be far out in left field when it comes to tubes. Maybe Crusher does have tube amp experiance but from the contents of his post I am thinking along the same lines as Doc. Above all,go slow and learn about tube ratings,voltages and biasing before trying to put something together.
I would look at the G3SEK control board if you're building a tube amp.
They are well documented and bulletproof.
They are well documented and bulletproof.
W5LZ,
i hope you know i was just having some fun with you. LOL
i do understand your hesitation.
as for the safety of building a tube amp versus building a solid state amp;
there really isnt too much difference until you are all finished and plug it into the wall is there?
seems to me that its perfectly safe to build either one; its when you turn it on that the safety factor comes into play. LOL
so, as long as crusher stands far away when he plugs it in, and flips the switch with a 6 ft. stick, while holding a fire extinguisher in the other hand; he should be fine right? LOL
good luck crusher, i hope you find the info you are looking for.
LC
i hope you know i was just having some fun with you. LOL
i do understand your hesitation.
as for the safety of building a tube amp versus building a solid state amp;
there really isnt too much difference until you are all finished and plug it into the wall is there?
seems to me that its perfectly safe to build either one; its when you turn it on that the safety factor comes into play. LOL
so, as long as crusher stands far away when he plugs it in, and flips the switch with a 6 ft. stick, while holding a fire extinguisher in the other hand; he should be fine right? LOL
good luck crusher, i hope you find the info you are looking for.
LC
LOL. Yeah i was looking up the 811A and yes I realize that if I build it CCS it will 1250V. Now I am use the low voltage/high current devices. Just the opposite of what tubes are. I found a schematic for a (4) 811A tube amp. Yes it is the first time building one from scratch.
When dealing with high voltage the potential to have an arc is MUCH higher. You need to make sure you have no sharp points on your solder connections on anything carrying high voltage.Also leave lots of space between voltage points and ground. If something arcs even once it can leave a carbon track that is nearly impossible to remove in some cases and the circuit will continue to arc in the same place.Component values in the output tank circuit and plate blocker must be able to withstand the DC voltage PLUS the RF voltage present.
Tube amplifiers and their HV power supplies are a lot more fun to watch at the initial testing phase (unless they happen to belong to you).
Lots more entertainment value! I've seen homebrew 4-400 amplifiers put on such a fireworks show when first powered up that the owner should have sold tickets! At least that way he could have collected enough money to get started on building the revised amplifier!
Lots more entertainment value! I've seen homebrew 4-400 amplifiers put on such a fireworks show when first powered up that the owner should have sold tickets! At least that way he could have collected enough money to get started on building the revised amplifier!
LOL. That was part of the reason to start with an 811A amplifier. Tubes are pretty cheap and are not as complex as some others. Like anything else have to start some where. Hey LC haven't talked to you in a long time good to see ya. I remember working on an old 50's-60's turntable. The electrolytics were smoking bad and some other stuff was bad. It took a long time getting that thing to work. Everything was tubes in the thing.
Try Googling for "811A amplifier" or look for a schematic of the Ameritron AL-811. It uses three 811A tubes and the old Heath HA-10 Warrior amp used four 811A's. Even a dual 572B tube amp like the Yaesu FL-2100 should be easy to copy and use 811A's. The voltage would have to be lower of course and the power output lower but the 572B's are basically an 811A on steroids.
I have a pair of National 811A's here,brand new never opened that I want to play around with as well. I was thinking about a small amp to run on 80m with my Heath DX-60 for a little boost when running AM. My only problem is all the transformers I have are more suited to running 4-400's or even a 4CX5000A.
I have a pair of National 811A's here,brand new never opened that I want to play around with as well. I was thinking about a small amp to run on 80m with my Heath DX-60 for a little boost when running AM. My only problem is all the transformers I have are more suited to running 4-400's or even a 4CX5000A.
hey crusher,
ran across this article in the archives.
maybe it will help you, maybe not. LOL
anyway, here ya go:
The Approx. Perfect Amplifier manuscript
later,
LC
ran across this article in the archives.
maybe it will help you, maybe not. LOL
anyway, here ya go:
The Approx. Perfect Amplifier manuscript
later,
LC
- No one is chatting at the moment.
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