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

Class D amp boards
Class D amp boards
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 10th April 2018, 03:26 AM   #1
michael crump is offline michael crump
diyAudio Member
 
Join Date: Apr 2018
Default Class D amp boards

Class D amplifier boards.
I've noticed many mixed reviews of such boards both being great and bad. And there's reasons why some will find these little amplifier boards bad. Other than that they're tiny and made in China. But consider th is, The chips that are the heart of these boards are made in the great USA. MAGA!! The Chinese folks just put them on pcbs with some additional components to make a functioning amplifier. Let's get one thing understood about audio amplifiers. They amplify whatever it is that is put into them. What ever that may be.
As we hobbyists to audiophiles like to tinker with our electronics, not everyone has the whole understanding of audio components. There's voltage and current, and the different sources of that. Some AC derived sources are "dirty". Meaning that they output a lot of unfiltered or poorly rectified ac noise into your circiut. Then there's the wiring. Some of the wires can and do pick up noise, just like an antenna. That can be fixed too. I've even read that a guy heard his refridgerator in his kitchen cycling through his class D amp board. Well, old cars used to have alternator whine. Next is distortion.
Most of us are familiar with the figures of 1% and 10% THD +N @ a number of watts @ ? ohms. But not to many takes into the consideration of what we are using to source our tunes with. And they are all different. Phones both Android and Iphones- different, and the different brands. Pocket mp3 players both quality ones and cheaper ones. Different even more. Desktop pc's and laptop pc's and then different brands. An old tape deck with or without a preamp. Note that I said preamp. Both home and professional equipment- different output levels. Said again- different output levels. They all vary from item to item. and the inputs of many different class D amplifier board differ. Here what some folks miss.
The input gain. Not enough, music is low, noise is more noticable. Sounds like a weak toy. Too much gain, lots of noise and distortion. Sounds like ****. Now if you knew how to get it right, it sounds wonderful. Question is do you need a preamp. Or is your source too heavy for your inputs. Now lets get to the good stuff.
As I have been tinkering with audio components for litterally decades, I've come to know a quite of bit. I also have a small collection of these Cheap little class D amp boards. The TDA's, TPA's and the PAM's too. They all have different gain inputs. Some of the OEP (tiniest) boards other than the PAM's have choosable gain inputs by just bridge soldering two tiny pads. 20DB, 32DB. ETC. And if you are going to use a powered preamp board. Some of them have tone and volume pots on them. Some are the BBE types. I just got one that has both BBE and Stereo Widener on it. There are some tone controllers that are passive. So here's some help. Don't chuck a board cause it don't sound right at your first try. Try another source or two. Try a different board. The only bad amp board is one that smokes as soon as you apply voltage to it. I've never had one of them. Here's some source and board combinations to consider.
The PAM boards, Their gain is good with phones and some pocket mp3 players. No good in cars, some tape decks and definitely not professional audio. Unless you change the gain. The TDA's and the TPA's vary board model to model but, they are best suited with a preamp. Can be use in vehicles and pro pa systems. Them tiny minimalist OEP are TDA's and TPA's with minimal components. They're the red tiny boards and they have the bridge solder tabs for different gain. So if you have loud distortion and loud noise, reduce your gain at the inputs. Ifyou have not enough volume and some noise, you best bet to need a preamp to increase your gain at the inputs. Then there are some combinations of source and amps that seem to be made for each other.
Have you seen them FM radio, bluetooth, usb, SD card module boards, usually black in color, Cheap plastic with the remote. Ebay, Amazon, Aliexpress, Thanksbuyer, etc. They go practically perfect with the PAM's. I use a passive tone volume board with them at the most. Some of the Bluetooth only boards work with the PAM's but some need a preamp. Some need reduction. I've found that I put a small resistor in series of the negative wire of the input works. I've used 1k, 5k and 10k as well as trim pots. Just try different resistors.
To conclude, I wish I had these little Class D amp boards back in the 80's when I was strapping old heavy car batteries, 20 expensive Duracell D batteries to my bicycle just to have cruise tunes. And back then. Even the cheapest car stereos were expensive. And them expensive D cells didn't last long and the car batteries were heavy on a bike. Even speakers are better. 3 inchers, 4 inchers. I remember the 6x9's I had on my chopper bike. And them little 1 watt 4 incher blew if I turned it up. And my first Boombox build. That was nice but, it was restricted to my shelf Ac-dc power supply. My first PAM 8610 sounded a lot better than my old Pioneer receiver did. It died years ago. I was thinking about ripping out them heatsinks and putting in a pair of TDA 8932's in. But something else may die in it. Best to build one from scratch.
I hope this help you with your builds and projects. Build large boomboxes and play it loud. Pedal in stereo. Put some tunes on your backpack while hiking. Phones and pocket players are nice, just like walkmans were. But nothings like bass in everyone's face. And also, efficient speakers make it just much more louder and better. My current build is a pam board 2.1 that has two pam chips putting out 30w sub and 2x15w left and right. Got that from Parts Espress. A efficient vintage 15 inch woofer and two vintage efficient 10 woofers, some planars and piezo's all (Ebay, Amazon, Junk in alley) three 26650 li ions. Sounds like my old Pioneer system with a shoulder strap. I do use lightweight boards and ABS sheets. Almost forgot. Another practice I do is to braid my input wires, speaker wires and power wires. And a loop or two through a ferrite donut cannot hurt either. Kill the noise. An extra capacitor on the power inputs too (Proper voltage). I also make my own led vu meters but you can find some prebuilt from China. Google LM 3914, 3915 and 3916. Look up Youtube for these too. Lots of choices and info. I also use the hard to find UAA180 (a2770) for led vu meters too. Learn how to etch pcb's or least use perf boards. I build just about anything, but you can too.
  Reply With Quote
Old 10th April 2018, 04:07 AM   #2
nigelwright7557 is offline nigelwright7557  United Kingdom
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
Its one thing knocking up a class d design, its quite another flogging it to death to see how it performs and making it better.

A lot of the Chinese designs are simply hacked western designs.
Sometimes it works ok but other times not due to bad pcb layout and/or cheap components.
__________________
PCBCAD51 download or CDROM 2019 version out now https://www.murtonpikesystems.co.uk
  Reply With Quote
Old 10th April 2018, 04:17 AM   #3
bwaslo is offline bwaslo  United States
Old guy with soldering iron
diyAudio Member
 
bwaslo's Avatar
 
Join Date: May 2006
Location: Portland, Oregon!
Class D amp boards
A class D amp isn't far from being an RF circuit instead of an audio circuit. Circuit layout and ground planes are EVERYTHING.
__________________
[W9MJE] Horn spreadsheet SynergyCalc/; SmallSyns SmallSyns;
Crossover design Xsim; Depot diffusor super-easy diffusors
  Reply With Quote
Old 10th April 2018, 05:45 AM   #4
Samsara is offline Samsara  France
diyAudio Member
 
Join Date: May 2011
Quote:
Originally Posted by michael crump View Post
The chips that are the heart of these boards are made in the great USA. MAGA!! The Chinese folks just put them on pcbs with some additional components to make a functioning amplifier.
Sound like great ****.

Quote:
Originally Posted by nigelwright7557 View Post
A lot of the Chinese designs are simply hacked western designs.
Which one?
For me, they use manufacturers PCB design.
  Reply With Quote
Old 4th March 2019, 11:43 AM   #5
gauravsanu is offline gauravsanu
diyAudio Member
 
gauravsanu's Avatar
 
Join Date: Sep 2016
Can you suggest me a very good amplifier board which can deliver excellent sound?
You can suggest me for 15+15 watt to 50+50 watt
  Reply With Quote
Old 4th March 2019, 01:48 PM   #6
FauxFrench is online now FauxFrench  France
diyAudio Member
 
Join Date: Dec 2017
Location: The mountains, calm and quiet.
The TPA3250 chip should be very nice. Give the elaborate thread a look. 3E Audio has such a board.
  Reply With Quote
Old 4th March 2019, 04:28 PM   #7
gauravsanu is offline gauravsanu
diyAudio Member
 
gauravsanu's Avatar
 
Join Date: Sep 2016
Quote:
Originally Posted by FauxFrench View Post
The TPA3250 chip should be very nice. Give the elaborate thread a look. 3E Audio has such a board.
Thanks for your reply
  Reply With Quote
Old 6th March 2019, 01:05 AM   #8
bwaslo is offline bwaslo  United States
Old guy with soldering iron
diyAudio Member
 
bwaslo's Avatar
 
Join Date: May 2006
Location: Portland, Oregon!
Class D amp boards
I'd look into an ICEpower 50ASX2SE. Better than most performance, and almost absurdly easy to get working, as the power supply is built onto the board, and no heat sinks need to be dealt with. AC line power in, speaker audio out.
ICEpower 50ASX2SE Class D Audio Amplifier with Power Supply Module 2 x 50W
__________________
[W9MJE] Horn spreadsheet SynergyCalc/; SmallSyns SmallSyns;
Crossover design Xsim; Depot diffusor super-easy diffusors
  Reply With Quote
Old 6th March 2019, 04:59 AM   #9
Antennaguru is offline Antennaguru  United States
diyAudio Member
 
Antennaguru's Avatar
 
Join Date: Oct 2016
Location: Rural New England
I have to second the IcePower recommendation as they have come down in price and sound very good. As mentioned they come complete as to power supply and all of the connections. The only quirk can be how low the output impedance of your preamp stage is. If it's very low then you will be fine without an input buffer stage, but if it's a higher output impedance preamp then you might need a buffer. The buffer stage is essentially what differentiates the use of these modules by different OEMs, and each has their own secret sauce.

The IcePower ASX modules have an input impedance of 5000 to 8000 ohms depending upon the model, and your preamp's output impedance must be less than 1/10th of that amount or the sound will be unpredictable. More typical power amplifiers have a higher input impedance of around 47,000 ohms, making them forgiving of connection to a wider range of preamp driving impedances.
  Reply With Quote
Old 6th March 2019, 05:07 AM   #10
cersepn is offline cersepn  United States
diyAudio Member
 
Join Date: Feb 2010
Has anyone done a pass b1/dcb1 buffer with the icepower module as an integrated setup? How were the audio results for you?


I assume with the b1/dcb1 buffer the output impedance will be good for the icepower input right?
  Reply With Quote

Reply


Class D amp boardsHide 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
2.1 class D mini amplifier boards? Pegasus123 Class D 0 30th June 2017 04:56 AM
FS: VFET/class A PSU boards Nisbeth Swap Meet 1 14th December 2016 06:55 PM
Comparison of (5) Class-D amp boards dc3 Class D 6 11th October 2016 05:51 PM
FS: MAX9709 Class-D Amplifier Boards 50*50 2*25/50W doctormord Swap Meet 0 10th April 2016 10:06 PM
Tons of class D boards on eBay here. EBBCO Parts 0 8th September 2012 12:17 AM


New To Site? Need Help?

All times are GMT. The time now is 04:31 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki