Hello, I have an AL-82, my habit is to turn it on, allow it to warm for about 5 minutes prior to use, use the amp, then turn it back off. Sometimes I find that I will be using the amp again within 10
The direct heat filament/cathode only needs few secondsv to work. If power supply of filment without inrush current limiter or soft start, you'd better keep it turn on in half hour. a good idea if yo
Leave it on. Filament time is better than the inrush current. The step start in the AL-82 is VERY short which can have high inrush current on the tube filaments. 73 Jim W7RY _________________________
Hello, Many thanks to all! I suspected the answers would tend towards the leave it on side of things, but wanted to ask to be sure... THANKS AGAIN TO ALL!!! Dave NK7Z ________________________________
I asked Alpha amps tech this question and otherwise the received wisdom over the years agrees with this.... Turn on is the worst thing that can happen to something with a filliament, like a light bul
Hello, I have an AL-82, my habit is to turn it on, allow it to warm for about 5 minutes prior to use, use the amp, then turn it back off. Sometimes I find that I will be using the amp again within 10
This is what I gather: The AL-82 manual specifies warm up time as "approximately 30 seconds" while the AL-80B manual states "10 seconds". I am guessing that the chimney type cooling VS the muffin fan
Nope, different manual writers; 30 seconds is better. Thats nothing new and just common sense copied from as far back as the first AC operated table radio.The military found that out also as the MTBF
Its too bad amps dont have a B+ On-Off switch such as the old NCL-2000 offered....saves a lot of unecessary hours on PS components. Leave just the filaments on. Carl KM1H ____________________________
Here is an idea to help instant on Tubes, reduce the cold to hot current shock cycles. I was going to say install a Variac in the filament circuit. Variacs to handle 200 watts are not so expensive an
Just my opinion: First: What do we cool on the tubes with forced air? On glass tubes which are cooled primarily by radiation, we are mainly cooling the seals. With external anode tubes we are cooling
Is there an official Eimac or other tube manufacturer data sheet that specifies warm-up/cool-down for a 3-500? I looked at an Eimac 3-500 sheet and must have missed it? ______________________________
Speaking of warm up times and filament life got me to thinking about a ramping switch system for the whole power supply. As I understand it there are devices which will chop up the AC sine wave into
It would likely be discussed in Care and Feeding or various Application Notes. All are available on the Internet. Bill Orr also wrote many articles for CQ and QST discussing cooling and other subject
Hi Mike, Have a look at: http://www.pc5m.net/projects/filament-inrush-protection Is in use for my TH289 (45amps of filament current) amplifier. Gl, Carel Speaking of warm up times and filament life g
Just use a Triac and let it ramp up the voltage over a few seconds...say 5 or 10. After the ramp up, switch out the Triac with a relay as they tend to be a bit noisy. Mostly it's the diac keying that
The data sheets I have do not list any warm up times. IOW, throw the switch and go. It does state that Inrush current should be limited to two times normal current during turn on to limit thermal str
I think it'd be well worth the effort, but I'm loathe to punch additional holes in the front panel of things that cost several thousand dollars and up. I'd actually like to be able to turn off the fi
I have been thinking about what Roger and Carl just mentioned about front panel modes that would be nice for amp flexibility. Why not find the best key fob short range on off switch widget out there,
Hi Mike, It could be done in the "old way" with a phase control using a Triac. See Unitrode Application Note U-83 http://www.ti.com/lit/ml/slup061/slup061.pdf or perhaps an old GE SCR handbook. A mod