Phaser Resistors Which Ones Carbon Film Or Metal?

[mattpas]

Hey guys,
I just bought the BYOC Phaser kit and noticed that it comes with Carbon Film resistors.
I have always heard that metal film are better for there low tolerance and low noise.
Has anyone tried the Phaser with both and which are better to use?

[zachomega]

I'm sure the difference is negligible at best.  Do yourself a favor and just use the resistors that came with the kit. 

-Zach

[MusicAudio]

For audio effects the tolerance is almost never a factor, as long as their reasonably close to the intended value. And Zach is dead on, there's probably going to be no audible difference between carbon and metal. Good luck on your build!

-mike

[Mark Hammer]

If it was a circuit which applied large amounts of gain, like a distortion or compressor would, then you would be sensible to be concerned about noise.  Phasers, however, typically provide very little, if any, gain to the signal so you are not amplifying any noise which may be contributed by resistors.

There are some legitimate concerns in some phasers about noise which may be added via the recirculation path.  One common way used to address this is to stick a small-value cap in the feedback loop of the last phase-shift section (or wherever it can do the work).  If it is a particularly complex phaser, like a 12-stager, every 4 stages is a frequently observed  strategy.

How small? If the feedback resistor is 10k, then a 1000pf cap in parallel will start to roll off top end around 15khz.  Since most guitar-amp speakers don't go out that high, a more effective value might be 1500 or even 1800pf, which would start to knock off any hiss you might actually be able to hear.  However, such a "cure" is really only necessary in a very few instances.  The BYOC phaser is a P90 clone, not generally known to have hiss issues.

[mattpas]

Thanks guys,
I figured Carbon in Phasers and also a chorus wouldn't be a problem but I always like to check first.

[mac]

Is there any criteria so as to know when it is better to use a MF? I was thinking if P=i*i*R > some value then use a MF.

mac