Tubes and Safety regs

[vibratoking]

Talking about what Fender and Marshall did.....

The newer caps may contain such strange guts that they do not need heat to keep the dielectric molten - I really haven't investigated this. However, the early caps (Mallory, Astron, LCR, and Daily) that Fender and Marshall used actually benefited from the heat because it helped them perform as designed. This is in part why fans were never used. With Marshall heads the vents on top were maybe a good idea because they didn't have much venting, not like a Fender combo or head. Eh, a tube orientation thing mostly. The Vox amps, too, which did/do get very hot.

That's interesting information that I have not heard before. How and why do the caps benefit from heat? So, are you saying that Fender and Marshall considered using fans, but did not because it benefitted the cap performance? That's new news to me.

I think that Mesa was the first company to use a fan? And it probably happened as a result of some customer pointing out that the tubes were getting hot, but not because it was needed.

I am guessing that you must have worked for Mesa in order to have that type of insider knowledge. It's hard to imagine that full product lines would have been changed to include a fan that wasn't needed.

Respectfully, are we really talking facts here?

[VacuumVoodoo]

Guess what main ingredient of the electrolyte in the caps is. Yes, it's water. You heat it up it evaporates. Read up on app notes from serious manufacturers, they all advise to keep the caps away from heat sources, they warm up due to current passing through them. The data sheets also show how the caps life gets shorter with higher ambient and operating temperature.
Anything about about keeping the electrolyte "molten" and Marshall placing the caps close to hot tubes on purpose is BS.

[xtian]

I think rooster was talking about Victorian era, steampunk amps, which need to be kept above 100°C to operate properly.

[Aurora]

In general terms, most of todays failures in consumer grade electronics, TVs mostly, is due to failing capacitors. Under-spec'ed, marginally spec'ed etc etc - using too low temp coeff's in the wong places - bad layout vs temp distribution, - pick your chioce... using 20c's parts instead of 1-2$ a piece makes a great deal of profit - or lower sales price to the competition...