carbon comp vs metal film in a new amp build?

[mikepukmel]

The metal film 1/2 watt are cheaper, and 1% tol, compared to carbon comp. Would using either one affect the tone or longevity of an amp? This is a new amp build.
Thanks.

[copperheadroads]

Specs makes it the perfect component doesn't it ? Now only if the made them look more like a Tootsie roll & squared edges & charge more for them ,they would be the prefect passive component for the job . Remember Customers hear with there eyesX$$$$= how much they will spend for tone/Snake oil .So in some perspective it is a pissing contest for consumers .

[mikepukmel]

Thanks copperheadroads. Im very new to electronics, reading all the time. Everything I can read says that the old carbon comps are a worse component. They absorb moisture, they get 'hissy', they even fall apart sometimes. They start wandering out of tolerance, sometimes before they're even off the shelf. I pinged a few other amp repairer/builders (few!), most are nice enough to reply a bit They say that they replace what 'looks like the same' component for real museum pieces, when they can get those components, mostly for the reasons you state.

But I have not been able to find anyone who has really built a few amps, some with CC's some with metal film's, and said that they could hear a difference.

With caps, ok, its a pretty complicated thing. So I could see how one cap construction type might be better for audio.

Anyway, it sounds like you've had no problems with metal film's either in amp repair work or new amps, for sound quality, longevity?

[mikepukmel]

Hard to beat that tootsie roll appeal, though.

[mikepukmel]

Heh, I almost spit my coffee out when I read this one.

"Some people need the sound of bacon frying to cover up the sound of their guitar playing, and for them God invented NOS carbon-composition resistors."

Resistor Advertising ? Tone Lizard

[mikepukmel]

I need a break. I just spent two hours trying to make sure I can identify where components are on the schematic, compared to the layout, then compared to photographs of a real vintage chassis. Two hours and one minute I realized the 7025's and 12AX7s are two tubes in one. So, the schematic has part of the pin layout drawn in the other half of the bottle. At least I got past that intellectual hurdle. Now I need to figure out which end of the soldering iron to plug into the wall....

[Tom Phillips]

... Now I need to figure out which end of the soldering iron to plug into the wall...

Also very important to figure out which end of the soldering iron to grab with you hand. Seriously - You are way ahead of some builders if you are taking the time to learn how the schematic (the language of electronic circuitry) relates to a layout.

PS: I do know someone who asked to be handed a soldering iron and, in a moment of inattention, grabbed it by the hot end and got a serious burn across the palm of his hand.

Cheers,
Tom

[pdf64]

For good reliability it's beneficial not to exceed half a resistor's dissipation rating, eg so if a 100k plate resistor is pushing 0.4W, consider using a 1 watt component. That's what Fender ended up doing by the late 70s, and those resistors rarely seem to go bad, unlike the 0.5W type used before that.
With tube circuits we need to check that a resistor's voltage rating is adequate. Most ~0.5W types are 350V, but some may only be 250V. It's a good idea to look for 500V types.

For analysis of how CC characteristics may affect tone, see http://www.geofex.com/Article_Folder...carboncomp.htm

[mikepukmel]

Thanks everyone!

[frus]

PS: I do know someone who asked to be handed a soldering iron and, in a moment of inattention, grabbed it by the hot end and got a serious burn across the palm of his hand.

was it this guy