Hello Mr. Paulo Ramirez,
Just my opinions to your good questions.
Vacuum tube electronic circuit reliability should be the same whether a PCB (printed circuit board) or point to point wiring technique is used provided both are connected to quality tube sockets and the circuit board is of proper thickness and mounted properly. Yes, to much heat on a circuit board can be a bad thing but they are pretty tough.
The heat generated by vacuum tubes is intentional as tubes requires high internal temperature to operate. A fan used to cool down the heat in a chassis so the other electronic elements do not overheat is a good idea but isn't always necessary. In many cases, tubes are mounted on the top of a chassis and open to air flow so no fan is required. There is some good discussion elsewhere about how adjusting/reducing the voltage to the tube heaters (filaments) can have some advantages but there must be enough heat to make them operate - another whole story for another time.
One thing that can prolong tube life is to have a slow warm up on the filaments. You may have noticed that household incandescent light bulbs usually burn out when you first turn on a light and rarely when they are already on. That is because the initial "shock" from going from 0 volts to 120 volts cause a sudden change on the tungsten filaments from room temperature to high temperature which causes them to break. The same can happen with tube filaments.
Installing inrush current limiters (a passive electronic component) of the proper value in the proper place (either on the filaments themselves or on the main power transformer - or both) can help reduce the initial high startup current. Inrush current limiters are beneficial for both tube and solid state designs if done properly. They are basically resistors that start with a higher resistance when cold and lower resistance (some near 0 ohms) after they heat up due to current flow passing through them. Other slow start up solutions are available but can become more costly or complex.
If tube equipment is designed properly, many vacuum tubes can and do last for decades. If the tube filament doesn't burn out and the tube is used well below it's maximum output ability, it can last for a very long time. I have some that are over 40 years old and still working - much like me - LOL.. :)
There is a lot more to your questions that we could discuss but that could get quite involved and I'm no expert but I'll be glad to discuss this further if you want to e-mail me at glassaudio@comcast.net
Brad
Just my opinions to your good questions.
Vacuum tube electronic circuit reliability should be the same whether a PCB (printed circuit board) or point to point wiring technique is used provided both are connected to quality tube sockets and the circuit board is of proper thickness and mounted properly. Yes, to much heat on a circuit board can be a bad thing but they are pretty tough.
The heat generated by vacuum tubes is intentional as tubes requires high internal temperature to operate. A fan used to cool down the heat in a chassis so the other electronic elements do not overheat is a good idea but isn't always necessary. In many cases, tubes are mounted on the top of a chassis and open to air flow so no fan is required. There is some good discussion elsewhere about how adjusting/reducing the voltage to the tube heaters (filaments) can have some advantages but there must be enough heat to make them operate - another whole story for another time.
One thing that can prolong tube life is to have a slow warm up on the filaments. You may have noticed that household incandescent light bulbs usually burn out when you first turn on a light and rarely when they are already on. That is because the initial "shock" from going from 0 volts to 120 volts cause a sudden change on the tungsten filaments from room temperature to high temperature which causes them to break. The same can happen with tube filaments.
Installing inrush current limiters (a passive electronic component) of the proper value in the proper place (either on the filaments themselves or on the main power transformer - or both) can help reduce the initial high startup current. Inrush current limiters are beneficial for both tube and solid state designs if done properly. They are basically resistors that start with a higher resistance when cold and lower resistance (some near 0 ohms) after they heat up due to current flow passing through them. Other slow start up solutions are available but can become more costly or complex.
If tube equipment is designed properly, many vacuum tubes can and do last for decades. If the tube filament doesn't burn out and the tube is used well below it's maximum output ability, it can last for a very long time. I have some that are over 40 years old and still working - much like me - LOL.. :)
There is a lot more to your questions that we could discuss but that could get quite involved and I'm no expert but I'll be glad to discuss this further if you want to e-mail me at glassaudio@comcast.net
Brad