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 Photo Gallery
Class D Amp Photo Gallery
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 August 2020, 09:59 PM   #1621
daniboun is offline daniboun  France
diyAudio Member
 
Join Date: Nov 2019
Location: Lyon (France)
Quote:
Originally Posted by redjr View Post
Hi all,

I'd like to present my latest class D amp build. At the core, this project was based on member xrk971's newest class D amp board. This board is based on the TI TPA3255 chipamp. The specifics of this amp can be found over at this link. The amp board is available as a bare PCB, or as completed PCB in his Esty store. ................
.
Nice build ! XRK boards are great and sound amazing
Nice case as well Did you buy it or DIY enclosure ?
Enjoy music )
  Reply With Quote
Old 10th August 2020, 10:45 PM   #1622
redjr is offline redjr  United States
diyAudio Member
 
Join Date: May 2011
Location: CT
Class D Amp Photo Gallery
Thx daniboun. The case is from ModuShop.
__________________
redjr
  Reply With Quote
Old 10th August 2020, 11:03 PM   #1623
Pygmy is offline Pygmy  Netherlands
diyAudio Member
 
Join Date: Jul 2016
Location: Haarlem
@redjr - When I follow your link to Etsy I don't see a finished board.
Is something wrong on my end or has he stopped selling finished boards?
  Reply With Quote
Old 10th August 2020, 11:40 PM   #1624
redjr is offline redjr  United States
diyAudio Member
 
Join Date: May 2011
Location: CT
Class D Amp Photo Gallery
I think they are still being offered. He may need to restock his store. I didn't see the amp board, but thought the site would still be useful. I'm not sure, but he may be doing another group buy in the thread first to evaluate interest before restocking.
__________________
redjr
  Reply With Quote
Old 11th August 2020, 02:50 AM   #1625
redjr is offline redjr  United States
diyAudio Member
 
Join Date: May 2011
Location: CT
Class D Amp Photo Gallery
Quote:
Originally Posted by Pygmy View Post
@redjr - When I follow your link to Etsy I don't see a finished board.
Is something wrong on my end or has he stopped selling finished boards?
The finished boards are sold out. The bare PCBs are there according to xrk971. He needs a group buy of 20 to manufacture more completed amps. Please see his thread.
__________________
redjr
  Reply With Quote
Old 11th August 2020, 06:01 AM   #1626
daniboun is offline daniboun  France
diyAudio Member
 
Join Date: Nov 2019
Location: Lyon (France)
Quote:
Originally Posted by redjr View Post
Thx daniboun. The case is from ModuShop.
Arfffff you should get it @ Audiophonics @ 37,90 euros

HIFI 2000 Boitier Galaxy GX383 80x330x230 - Audiophonics

H2000 cases are cool and made in Italy. I use those cases for many projetcs as well.
  Reply With Quote
Old 11th August 2020, 06:14 AM   #1627
drMordor is offline drMordor  Russian Federation
diyAudio Member
 
drMordor's Avatar
 
Join Date: Sep 2019
Location: Moscow
Class D Amp Photo Gallery
Quote:
Originally Posted by redjr View Post

After testing on my bench, I found that the SMPS600 and the amp did not play nice together due to excessive amount of inrush current from the SMPS to the amp. A different kind of soft-start was required, since the SMPS already had a soft-start built-in. .
Need replace one cap in SMPS PCB, for bigest time softstart.
  Reply With Quote
Old 11th August 2020, 06:18 AM   #1628
drMordor is offline drMordor  Russian Federation
diyAudio Member
 
drMordor's Avatar
 
Join Date: Sep 2019
Location: Moscow
Class D Amp Photo Gallery
Quote:
Originally Posted by daniboun View Post
Best "chinese" board = 3E Audio or Aiyima 3251 (Tilear PCB) with OPA1656
Another alternative (but non PFFB enabled) :
replace the inductors after purchase
only ferrite or red ring
  Reply With Quote
Old 11th August 2020, 06:25 AM   #1629
bitinhvi is offline bitinhvi  Viet Nam
diyAudio Member
 
Join Date: Jul 2007
Location: Hanoi
Send a message via Yahoo to bitinhvi
Hi Redjr,

Is this board able to drive subwoofer?

I will need ~400W per sub (02 channel).

Does XRK sell populated PCB?

Thank you.


Quote:
Originally Posted by redjr View Post
Hi all,

I'd like to present my latest class D amp build. At the core, this project was based on member xrk971's newest class D amp board. This board is based on the TI TPA3255 chipamp. The specifics of this amp can be found over at this link. The amp board is available as a bare PCB, or as completed PCB in his Esty store.

The Hardware --

The TPA3255 chip itself is mounted upside down on the underside of the board to make mounting to a chassis a good option. Of course, there are other options to raise the board, traditional heatsink, fan, etc. could be used for cooling as well. What worked well for me was to use a 130mm x 44mm x 6mm piece of aluminum stock, bolted to the chip via the PCB using thermal pad/tape to the bottom of the enclosure. The whole amp assembly secured with 6mm brass standoffs. Note: The heatsink MUST BE electrically isolated from the chassis.

For the PSU I used a Connex SMPS600RS. This is 48VDC single rail SMPS with available auxiliary voltage of +12V. The 12v was necessary for 2 additional boards I used in my build - explained next. I have excellent success using the Connex line of SMPS' over the years in several projects. Highly recommended.

The blue PCB shown attached to the back panel with XLR connectors in the upper right, is the SE to Balanced board since the amp operates natively in BTL (Bridge Tied Load) mode. This allows both balanced and unbalanced (RCA) input connectors. I recently upgraded my heavily modded ES90938Q2M DAC with Balanced outputs, so wanted that capability.

After testing on my bench, I found that the SMPS600 and the amp did not play nice together due to excessive amount of inrush current from the SMPS to the amp. A different kind of soft-start was required, since the SMPS already had a soft-start built-in. What was needed was an inrush current limiter circuit between the SMPS and amp. I contacted xrk971, and with his help, an inrush current limiter PCB was born. It will be offered in his Esty store in the future. The prototype I tested worked fine and I was able to complete the project build. Note: This appears to only be an issue with some models of SMPS' and the amp. So if you're building this amp, please try your intended SMPS first, as it may work fine. xrk971 confirmed it worked with a different model of SMPS from Connex he used for testing. So this simply may be a one-off obscure occurrence. In fact, it worked with a lower voltage/power SMPS I tried as well - without the inrush current limiter circuit being necessary. The Inrush Current Limiter circuit is powered by the SMSP auxiliary 12v output.

The Sound --

I have to say that I have build a number of class D amps, and by far this is the best sounding DIY solution I have found. The first thing I immediately noticed was how quiet this amp is. There is nothing but silence when it's turned on. Then when the music starts.... wow! While class D amps may have a 'bright' overall sound, in my listening to it over the past several weeks, I never found this amp harsh, or fatiguing to listen to in any way. Instead, the sound is smooth, full-bodied yet very articulate in executing the music with clarity and detail. With plenty of wonderful and warm sounding mids, and solid bass when called upon.

While I primarily listen to digital streaming from my home media server(roon), I also listen to LPs. One of the best, more recent LPs in my collection that is an absolute pleasure to listen to, is James Taylor's 'America Standard' Limited Edition, double 180gram, Audiophile 45RPM LP set. This is one of the best mastered LPs I've ever owned. All sides were click and pop free while being played back on my vintage turntable; JVC QL-7 using a Denon DL-103 MC cartridge. The cartridge is paired with a Puffin DSP phono preamp. The dynamics of this LP set were stunning, easily rivaling many digital tracks. James' voice is simply transformed in such a magical, and very easy to listen to way.

I continue to be amazed at how well this amp sounds and the technical execution of the music. And, did I say I haven't even tested a full balanced signal chain from my DAC to amp yet? Next up.

A few more pictures of my amp along it's build journey.
  Reply With Quote
Old 11th August 2020, 07:18 AM   #1630
drMordor is offline drMordor  Russian Federation
diyAudio Member
 
drMordor's Avatar
 
Join Date: Sep 2019
Location: Moscow
Class D Amp Photo Gallery
Quote:
Is this board able to drive subwoofer?
I will need ~400W per sub (02 channel).
What is the resistance of the sub coil?
I tested 3255 at 62V, over 400 watts in PBTL mode at 4 ohms

Last edited by drMordor; 11th August 2020 at 07:22 AM.
  Reply With Quote

Reply


Class D Amp Photo GalleryHide 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


New To Site? Need Help?

All times are GMT. The time now is 01:52 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki