Guitar Potentiometers part 5, Comparing Tone Pot Tapers

http://www.planetz.com/?p=302 .
In this quick video, I compare linear taper 500k and log/audio 500k taper pots for use as a tone control. The pickup is wired to the jack, with the pot/cap in parallel, just like a normal guitar circuit (but without the volume pots). I'm using an Orange Drop .022uF, and the two pots are Bourns A500K and Philmore B500k.

Audio examples recorded through my Vox VT30 amp and a high quality Rode NT1 mic.

Please see my other potentiometer videos for more detailed background info on potentiometer construction, operation and tapers.

Category:

Howto & Style

Tags:

• potentiometer
• pot
• Bourns
• PDB241-GTR01
• Philmore
• B500k
• audio
• log
• logarithmic
• linear
• taper
• electronics
• P-90
• pickups
• Epiphone
• Riviera
• P93
• orange
• drop
• .022uf
• capacitor
• DIY
• howto
• Vox
• VT30
• Rode
• NT1
• Canon
• Hf200
• Sony
• Vegas

[muaythai4lifelife]

Hi John! Why some CTS pots have the bottom -flat- and others have the center with that kind of circled hole?

I noticed that difference in both 250,500,A,B pots.

[johnplanetz]

@muaythai4lifelife - as I understand it, there is slightly less torque in the pots with the channel in the bottom, due to less contact surface area on the underside of the pot. See my planetz blog post "New CTS Guitar Pots" on January 22, 2010.

[muaythai4lifelife]

@johnplanetz just read! ;) i took a look at the datasheet too. i was wondering... how can i order a 25K ohm reverse log? i never found any on the net...

only 250 or 500k Ohm

[johnplanetz]

@muaythai4lifelife - i'm not sure CTS makes them, but you can find Alpha 16mm reverse audio taper pots at mouser

[muaythai4lifelife]

@johnplanetz thanx angain! ;)

[muaythai4lifelife]

@johnplanetz thanx John, i run to watch it!

[vikenemesh]

@johnplanetz n^2 is quadratic or parabolic, whereas 2^n would be exponential, but in practical usage n^2 approximates 2^n close enough. But as long as it sound anywhere near to logarithmic I'm fine.

[johnplanetz]

@vikenemesh - you're right that log is inverse of exponential. The audio taper is a typical n^2 exponential curve, but everyone in the potentiometer and guitar world refers to audio-taper pots as log curves. And the (rare and unusual) pots which have a natural (fast rise) log curve taper are called anti-log or reverse-log. Go figure.

[vikenemesh]

But if you were to reverse connect the pot, it would go slow at the beginning and rise fast at the end. But still not exponential, just mirrored log.

[vikenemesh]

@johnplanetz You're wrong on that, log refers to a logarithmic curve, and logarithmic is the exact (really) opposite of exponential, so about every logarithmic curve is very steep at the beginning and then the curve get's flatter.