proximity of cathode resistors and bypass caps - Is this really an issue??

[texwest]

I've heard it said many times that the preamp bypass resistors shouldn't be too close to the bypass caps. That the resistors get too hot and can damage the caps. I've seen several boutique amps where the builders put the resistor right on top of the cap and wrap the leads around the caps leads.  It makes me wonder if this is really an issue or not? Opinions?

[pdf64]

Any idea where you’ve heard that?
Heat is a stress factor for everything. Stuff that gets hot should have either heatsinking or a bit of free space around it, to allow air to cool / convect heat away. And avoid physical contact with other components, as conduction will heat the other thing.

Preamp cathode resistors don’t dissipate much heat, so the above isn’t really a consideration. Whereas power amp cathode resistors do dissipate heat, so it’s poor practice to mount their bypass caps tight against them. Rather allow air to circulate around it.

[texwest]

Any idea where you’ve heard that?
Heat is a stress factor for everything. Stuff that gets hot should have either heatsinking or a bit of free space around it, to allow air to cool / convect heat away. And avoid physical contact with other components, as conduction will heat the other thing.

Preamp cathode resistors don’t dissipate much heat, so the above isn’t really a consideration. Whereas power amp cathode resistors do dissipate heat, so it’s poor practice to mount their bypass caps tight against them. Rather allow air to circulate around it.

Those were my thoughts exactly.  Those preamp cathode resistors with 2 volts or less don't seem like they would get very hot, but power cathode resistors would get hot.

I can't remember where I heard this, but I know I recently saw comments on amp forums on facebook where people post their builds and there are those that keep saying you shouldn't put preamp cathode resistors too close to cathode caps.  I think it may be a fashionable thing to say now. 

Thanks

[sluckey]

I've heard it said many times that the preamp bypass resistors shouldn't be too close to the bypass caps. That the resistors get too hot and can damage the caps.

That's just people that don't know what they're talking about repeating stuff they've read from people that don't know what they're talking about, etc., etc. Ignorance upon ignorance.

A 1500Ω resistor with 2V across it will dissipate .0027 watts of heat!

[texwest]

I've heard it said many times that the preamp bypass resistors shouldn't be too close to the bypass caps. That the resistors get too hot and can damage the caps.

That's just people that don't know what they're talking about repeating stuff they've read from people that don't know what they're talking about, etc., etc. Ignorance upon ignorance.

A 1500Ω resistor with 2V across it will dissipate .0027 watts of heat!

Exactly, but wanted to hear it from the experts on here.  Thanks