How to add a Volume control to an audio circuit - Page 1
Forum section: electronics / beginners

author: Midphase
author_rank: Regular Contributor
timestamp: February 18, 2025, 03:00:22 am
content: Howdy, here's another question that is stumping me. I want to be able to control the output level of this circuit. My thought was to simply replace R83/R84 (or alternatively R86/R87) with a 10K pot, but when I tried it it yielded a distorted output and sound, particularly at the top end of the turn.What would be my best option for adding a simple output level knob (this being a stereo output, I assume I would need a dual potentiometer)?Many thanks!Juno Chorus Clone Schematic.pdf(411.75 kB - downloaded 92 times.)

author: coromonadalix
author_rank: Super Contributor
timestamp: February 18, 2025, 03:11:37 am
content: rv5 should be already a level adjusteror after c19 add a pot ?

author: themadhippy
author_rank: Super Contributor
timestamp: February 18, 2025, 03:56:08 am
content: leave those resistors alone.Take audio out pin 1 to one end of a pot,other end to ground and the pot wiper is the new audio out

author: Midphase
author_rank: Regular Contributor
timestamp: February 18, 2025, 06:25:23 am
content: "Take audio out pin 1 to one end of a pot, other end to ground and the pot wiper is the new audio out"Thanks. Should I buffer the output from Pin 1 through an opamp or is that not necessary?

author: MrAl
author_rank: Super Contributor
timestamp: February 18, 2025, 02:27:04 pm
content: Quote from: Midphase on February 18, 2025, 03:00:22 amAnother thing to think about is do you want to use an audio taper potentiometer. They are usually used for audio because of the way humans perceive loudness.

author: themadhippy
author_rank: Super Contributor
timestamp: February 18, 2025, 02:57:25 pm
content: Quoteor more commonly known as a log pot

author: Midphase
author_rank: Regular Contributor
timestamp: February 18, 2025, 05:02:59 pm
content: Curious why you are suggesting that I use a 2.2K potentiometer? I'm not sure I've ever seen one.P.S.Yes, I am planning on using A type LOG pots for this. Ideally a dual taper one since it would have to be a single knob that controls both left and right output levels simultaneously (unless there is a different way to do that with a single?).

author: Zero999
author_rank: Super Contributor
timestamp: February 18, 2025, 06:47:49 pm
content: Quote from: Midphase on February 18, 2025, 05:02:59 pmI just chose 2k2, because it's double the 1k series resistor. It should be fine with 1k or 4k7.Potentiometers tend to follow a 1k, 2k2 4k7 E3 series, although 2k2 is often rounded to 2k or 2k5 and 4k7 to 5k.I only showed one channel. There isn't any way to do i with a single potentiometer, unless you use something fancy such as an MCU with an ADC and digital potentiometer, or voltage controlled gain stage.

author: Midphase
author_rank: Regular Contributor
timestamp: February 18, 2025, 07:29:26 pm
content: Quote from: Zero999 on February 18, 2025, 06:47:49 pmI was under the impression that a dual gang potentiometer was designed to control two signals simultaneously? Am I incorrect in that assumption?https://www.digikey.com/en/products/detail/bourns-inc/PDB182-K415K-104B3/2218416?gclsrc=aw.ds&&utm_adgroup=&utm_source=google&utm_medium=cpc&utm_campaign=PMax%20Shopping_Product_Low%20ROAS%20Categories&utm_term=&utm_content=&utm_id=go_cmp-20243063506_adg-_ad-__dev-c_ext-_prd-2218416_sig-EAIaIQobChMI56v3q_rNiwMVii5ECB2DUyKMEAQYASABEgK5fPD_BwE&gad_source=1&gbraid=0AAAAADrbLlj5Ba-WyCJ3vGtKRK1mHPwZ0&gclid=EAIaIQobChMI56v3q_rNiwMVii5ECB2DUyKMEAQYASABEgK5fPD_BwE

author: Zero999
author_rank: Super Contributor
timestamp: February 18, 2025, 10:22:02 pm
content: Quote from: Midphase on February 18, 2025, 07:29:26 pmYes, a dual gang potentiometer will control two signals simultaneously and is two potentiometers in one package.