[resolved] Converting Stereo Board to Mono Output - Page 1
Forum section: electronics / projects

author: lamoule74
author_rank: Contributor
timestamp: June 11, 2025, 08:45:42 am
content: Hello everyone,I recently got this stereo amplifier module from Amazon:https://www.amazon.fr/dp/B082VD22BKI’d like to use it in mono mode to drive a single speaker with the combined power of both channels. IMy questions:Is it possible to modify this exact board to operate in mono ?Is there a safe way to bridge the two channels or reroute the inputs/outputs without damaging the IC?I've tried that schematic, didn't worked...https://www.sonelec-musique.com/images/electronique_stereo_vers_mono_001b.gifThanks in advance for your insights!Best regards,

author: Jeroen3
author_rank: Super Contributor
timestamp: June 11, 2025, 09:23:18 am
content: It's complicated with this type of amplifier chip (PAM8610). If you wire the outputs directly in parallel you can get a short circuit.https://www.mouser.com/datasheet/2/115/PAM8610-247304.pdfTI wrote some related application notes for similar amplifier IC's (TPA3100D2), but in that datasheet they explicitly mention it supports BTL mode.https://www.ti.com/lit/an/slaa822/slaa822.pdfhttps://www.ti.com/lit/an/sloa121a/sloa121a.pdfI would recommend finding a different chip. It's way easier to convert stereo to mono on the input side, as the schematic you've already found shown, and use a single channel amplifier.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 11, 2025, 10:05:55 am
content: It's a bit silly to want to bridge audio amplifiers in that small power range.Just buying a board that is suitable for the application probably also costs < USD 10. How much time do you want to spend in figuring out all the details of how to do the modification, and then still have the risk of blowing up your board?There used to be plenty of class AB audio amplifier chips that were bridged by design, or could easily be bridged by design. This was exspecially interesting in the automobile market, where they have to operate on low battery voltages. But the modern things all use Class D (or further in the letter soup) and that is very much different.

author: JohanH
author_rank: Frequent Contributor
timestamp: June 11, 2025, 12:52:38 pm
content: It's easier to make a mono signal before sending it to the amplifier, then just use one of the channels. You can safely combine any line level audio stereo signal by using a pair of resistors in series. See for instancehttps://www.instructables.com/Simple-Way-to-Convert-Stereo-to-Mono/

author: Zero999
author_rank: Super Contributor
timestamp: June 11, 2025, 01:44:00 pm
content: Quote from: JohanH on June 11, 2025, 12:52:38 pmYes, that's the way to do it.Because the channels are already bridged, then even if it were possible to connect them in parallel, it won't gain you much in terms of output power. Perhaps slightly lower losses, but that's it.

author: lamoule74
author_rank: Contributor
timestamp: June 11, 2025, 01:45:46 pm
content: @AllTo be honest ordering a stereo amp was a mistake,I was simply trying to figure out how make it works with all I have on hand...@JohanHQuoteyes that's what I was thinking.@Doctorandus_PQuoteThank you.Quoteblowing up, totally!Damage, yes, probably, but I think that if this set-up with such a small amp blows up in my face, maybe I can get some views on YT@Jeroen3Thank you for this documentation.

author: CaptDon
author_rank: Super Contributor
timestamp: June 11, 2025, 01:52:46 pm
content: Each half of that stereo amplifier is already working in bridge mode, therefore inverting one signal and connecting the speaker across both amplifiers will not produce any additional gain. Unless the PWM clock was syncronis for both channels it may do damage trying to parallel the amplifiers for more current driving a lower impedance speaker.