Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Class D Switching Power Amplifiers and Power D/A conversion

music stutter
music stutter
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th February 2018, 11:52 AM   #1
Jabie5 is offline Jabie5
diyAudio Member
 
Join Date: Feb 2018
Default music stutter

hi guys, I had a look through the forum but could not find an answer to my problem.
My son has built a little Bluetooth/mp3 project. The problem we are having is when the volume on the mp3/Bluetooth player board is increased the music starts to stutter. I have included links to the used items as I can not find out how to include the pictures, I hope this is ok.

I have tried 2 power sources: mains adapter 19v 1.75a and 16.8v (18650) batteries.

any help would be appreciated

jabie5



35W TDA8932 Digital Amplifier Board Module Mono Low Power Stereo Amplifier | eBay

Wireless Bluetooth MP3 Decoder Board Module BLE 4.1 Micro USB TF Card Interface | eBay
Attached Images
File Type: jpg bluetooth module.jpg (214.5 KB, 49 views)
File Type: jpg TDA8932 35w amp.jpg (134.2 KB, 49 views)
  Reply With Quote
Old 9th February 2018, 05:14 PM   #2
Khron is online now Khron  Finland
diyAudio Member
 
Join Date: Jul 2005
Location: Finland
Send a message via AIM to Khron Send a message via MSN to Khron Send a message via Yahoo to Khron
What speakers are you using?
__________________
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans
  Reply With Quote
Old 9th February 2018, 05:37 PM   #3
Jabie5 is offline Jabie5
diyAudio Member
 
Join Date: Feb 2018
60 watts (peak i would think) 4 OHMS

Peiying PY-3510C 87mm 3.2 Inch 60W 2-Way Car Coaxial Speakers Door/Shelf Pair | eBay
  Reply With Quote
Old 9th February 2018, 06:04 PM   #4
Khron is online now Khron  Finland
diyAudio Member
 
Join Date: Jul 2005
Location: Finland
Send a message via AIM to Khron Send a message via MSN to Khron Send a message via Yahoo to Khron
Well, at least according to the datasheet, at 19v you'd be getting maybe around 30watts, but with a 4ohm bridge-tied load that means you're awfully close to the overcurrent protection trip point, so... There's a chance that might be the explanation.

Makes sense if you think about it, especially if it sounds ok at lower volumes. Either that, or (especially with bass-heavy music) you're overdriving the woofer (especially in free air).
__________________
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans
  Reply With Quote
Old 9th February 2018, 06:46 PM   #5
Jabie5 is offline Jabie5
diyAudio Member
 
Join Date: Feb 2018
I'm new to this audio/amp stuff. so I'm not sure what you mean. so can you suggest a remedy for my problem. because at first I thought it might be to much output from the mp3 module going into the amp.
  Reply With Quote
Old 9th February 2018, 06:59 PM   #6
ICG is offline ICG  Germany
diyAudio Member
 
ICG's Avatar
 
Join Date: Jul 2007
Location: I had a Déjà Moo - I've seen that BS before!
Yes, you are very likely maxing out the current. The datasheet (PDF) tells you'll get a maximum of 17.2W out of the bridged (mono) configuration at 4 Ohm and that's already at just 12V. With the higher voltage you are using the maximum current is already reached at a lower output power since the losses are much higher, the efficiency is rather low because of the mismatched voltage and load impedance. You probably get only around 10W (likely even less), the rest is heat dissipation and it shuts down quite early because of said current limit and/or heat.

The mono TDA8932 boards do not perform exceptionally well at low impedances, even if they are great at 8 Ohm, keep in mind, they are not specified for 4 Ohm in BTL. There are better suited cheap amps for such impedances like the cheap TPA3118 boards and I'd suggest you use some of those.

If you still want to use the TDA8932 boards anyway, I'd suggest you lower the voltage to said 12V and also add small heatsinks, both improves the performance greatly. I've added heatsinks similar to these (ebay) and they perform much better at higher power but they will still not like low impedances. Just keep in mind they still need ventilation slots.

Another option would be to split up the BTL configuration and use them in the SE mode (look into the TDA8932 thread how it's done), that does not give you more power than the lower voltage in BTL mode but you don't have to use a different power supply/batteries and it shuts down much later because of the higher efficiency at such voltage/loads.

If you want to use the TDA8932 at low impedances it's also a good idea to swap the output filter inductors for toroidial coils with a higher maximum current, that lowers the distortion because they go into saturation much later. And you can (up to) halve the inductance if you find the highs too dull, that's because of the interaction of the output filter with the load impedance at the treble. These core coils are pretty cheap (I bought 20pcs for ~5 bucks) and a good potential tuning measurement.
__________________
I had a Déjà Moo - I've seen that BS before!
  Reply With Quote
Old 9th February 2018, 07:23 PM   #7
Jabie5 is offline Jabie5
diyAudio Member
 
Join Date: Feb 2018
I lowered the voltage to 12v and it still happens. I will look at the other board you have suggested
  Reply With Quote
Old 9th February 2018, 07:40 PM   #8
ICG is offline ICG  Germany
diyAudio Member
 
ICG's Avatar
 
Join Date: Jul 2007
Location: I had a Déjà Moo - I've seen that BS before!
I bought these amps, extremely cheap and they seem to perform well, it was just a very brief test run though. They will profit a lot from heatsinks too.
__________________
I had a Déjà Moo - I've seen that BS before!
  Reply With Quote

Reply


music stutterHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Good DIY 2.1 amp for Music/HT (70% music) benniehanas Class D 0 21st March 2016 06:29 PM
Asus Essense ST Music Card - Studio or Music KnightAngel PC Based 12 2nd October 2014 04:37 PM
Trust Music, the new music platform I founded FlorianB Music 0 2nd August 2014 01:06 AM
The Music FraserSoft The Lounge 31 7th September 2012 07:13 PM
JE Labs 300b round 5. MUSIC!! MUSIC!! TubeHound Tubes / Valves 14 11th January 2003 12:02 AM


New To Site? Need Help?

All times are GMT. The time now is 05:23 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki