How far away can a speaker cone be from a power tube?

marshalltsl

marshalltsl

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Hi.
Recently I bought a Marshall DR 4501 and I intall It into a Astoria Custom cabinet but making it a new rear wod panel because 4501 chassis is more width than Astoria chassis. The problem a power tube is less than 1cm ( 0,39 inches) from speaker con. It's so close. Could the cardboard speaker con cath fire?
No way I want moded Astoria speaker panel.
I decline intall It into Astoria cabinet. I swap speakers. G12-75T into Astoria cabinet. I put 4501 chassis into home made cabinet. Because I handle It better and It has better ventilation. Top part 4501 cabinet was so hot last time I played It. It Just has open back cabinet ventilation on it. Summer weather is here.
How far away can a speaker cone be from a power tube?

Thanks
 

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marshalltsl said:
Hi.
Recently I bought a Marshall DR 4501 and I intall It into a Astoria Custom cabinet but making it a new rear wod panel because 4501 chassis is more width than Astoria chassis. The problem a power tube is less than 1cm ( 0,39 inches) from speaker con. It's so close. Could the cardboard speaker con cath fire?
No way I want moded Astoria speaker panel.
I decline intall It into Astoria cabinet. I swap speakers. G12-75T into Astoria cabinet. I put 4501 chassis into home made cabinet. Because I handle It better and It has better ventilation. Top part 4501 cabinet was so hot last time I played It. It Just has open back cabinet ventilation on it. Summer weather is here.
How far away can a speaker cone be from a power tube?

Thanks
Click to expand...
Way closer than my level of comfort.
 
That's pretty close honestly. Lots of heat can build up off those tubes as we're all aware, roughly 110-175 degrees Celsius/230-347 degrees Fahrenheit on average, with some temperatures going even slightly higher depending on the type of tube.

The material of the speakers however, could dictate whether or not they could ignite and damage. Most speakers are made of paper and aramid fiber. Paper flashpoint is 480 degrees Fahrenheit ( not 451 as the great novelist Ray Bradbury had us believe!), while aramid fiber is nearly considered heat/flame-resistant due to its extremely high flashpoint of over 932 degrees Fahrenheit.

So, long story short: could the tubes theoretically ignite your speaker? Pretty doubtful. But what it can do, is began breaking down the speaker materials from near-direct prolonged heat exposure, rendering it possibly brittle and reducing it's sound and quality.


And that concludes the fake Professor Mike's lesson lmao
 
Thatbastarddon said:
Don’t forget about the fact that the speaker could possibly be more dangerous to the tube, and its life expectancy. Speakers create sound through vibration. Vibrating tubes can do bad things.
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✓ this!

@Thatbastarddon is absolutely right in it possibly causing the tube to become "microphonic". At best, you'll get a terrible sound quality and noise. At worst, it destroys the tube essentially
 
CoyotesGator said:
Things brings up an interesting point,
I don't think sound waves are going to hurt power tube in this situation BUT,
Will cone travel make physical impact the tube?

1CM is within travel of the cone.
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Completely possible honestly. He's talking less than 3/8" which is insanely close for vibration, especially if the speaker is pushing back and forth enough
 
CoyotesGator said:
1CM is within travel of the cone.
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Yeah! 1CM is within travel of the cone. I decline install It. Also I don't like stock 4501 cabinet. It's so small and sounds so thin. Playing It with his stock speaker into Astoria cabinet the amp sounds much better. Cabinets are really important. Speakers panel the bigger the better. A Marshall 1936 cab it's way better than a 1922 cab IMHO.
 

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