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

TI TPA3255EVM
TI TPA3255EVM
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 14th February 2018, 04:46 AM   #541
chromic is offline chromic  India
diyAudio Member
 
Join Date: Oct 2014
@nanoloop, reading ESP is the reason I even know about bi-amping
I guess using the EVM in SE mode isn't the way to go, then. Thanks.
  Reply With Quote
Old 14th February 2018, 04:58 AM   #542
Nanoloop is offline Nanoloop  Hong Kong
diyAudio Member
 
Join Date: Feb 2013
Location: Beyond Infinity
Quote:
Originally Posted by chromic View Post
@nanoloop, reading ESP is the reason I even know about bi-amping
I guess using the EVM in SE mode isn't the way to go, then. Thanks.
me too, and bi-amping really is magic - lower IMD is a clarity revelation .
__________________
  Reply With Quote
Old 14th February 2018, 08:33 AM   #543
robinlawrie is offline robinlawrie  United Kingdom
diyAudio Member
 
Join Date: Feb 2008
Quote:
Originally Posted by Nanoloop View Post
Both measured performance and subjective sound quality are worse using single ended than using BTL. I bi amp using a modified DBX234XL (discontinued so they are US$20 on Taobao) and 2 stereo BTL amps.

Everything you could want to know about bi-amping including schematics and parts calculator is Here thanks to Rod Elliott.
do you have any links showing SE mode is worse than BTL? never read that anywhere, ive configured mine as 2.1, with two SE channels running a fullrange driver each, with a gentle lowpass on one, before amp.

rather than a btl channel driving two drivers.. this was decided since the power output matches the drivers better in se mode, and the impedance of the drivers matches the amp better.
  Reply With Quote
Old 14th February 2018, 08:43 AM   #544
robinlawrie is offline robinlawrie  United Kingdom
diyAudio Member
 
Join Date: Feb 2008
Quote:
Originally Posted by ccss View Post
when playing through the subs and noticing distortion, is the CLIP indicator lit or blinking? also, what resistance are the subs?
you did an amazing job getting everything in that case!
also great job on the cooling solution...how is that working?

Hi , no clip indicator lit.. ive got everything crossed that the amp is fine and the nastiness i can hear is due to caseless drivers. hardly an ideal setup to test SQ of an amp.. ill just have to wait.


thanks for the compliment, yeah it was a REAL challenge fitting everything in, much harder than initially anticipated. in the 3d model it all slotted in very comfortably with nice spaces around each element. when i actually came to put it together , i noticed all the things i had not considered in my model.. practically every component in the amp had to be modified in some way to fit. its taken the best part of 4 months (just a little every evening after kid is sleeping, and taking it v slow so i didnt have to undo too many mistakes) but now, assuming this distortion thing isnt a thing, im very happy with the result. amp is quiet, and tiny, and very powerful. bluetooth has incredible range with antenna mod, frontpanel minidsp control hack works perfectly..


wrt the cooling. it -seems- to work, but ive not had proper speakers to crank it with, so ive not done a stress test yet.

im not worried about the amps, they have= big heatsink and 4x 60w heatpipes to shift the heat.. before installing i put a small blowtorch to the "hot" end of the cooling system, and after 5 mins, heatsink was hot, but i could still basically touch the "hot" end.. so that seems positive.

the psu is a bit more of a question mark.. at the mo all the power semiconductors are connected to case wall via a single 60w heatpipe, but i also have another 70w flatpipe which connects same block to case lid when all is proven working.. however ive noticed that the smps transformer gets quite hot, after an hour of running at (very) low volume, the trafo is up to about 50 degrees.. if that increases drastically under load i might have a problem and be forced to consider a fan.. which is another thing to squeeze in!!
  Reply With Quote
Old 14th February 2018, 10:19 AM   #545
Nanoloop is offline Nanoloop  Hong Kong
diyAudio Member
 
Join Date: Feb 2013
Location: Beyond Infinity
Quote:
Originally Posted by robinlawrie View Post
do you have any links showing SE mode is worse than BTL? never read that anywhere, ive configured mine as 2.1, with two SE channels running a fullrange driver each, with a gentle lowpass on one, before amp.

rather than a btl channel driving two drivers.. this was decided since the power output matches the drivers better in se mode, and the impedance of the drivers matches the amp better.
The measured performance is in the TI datasheets and it also stands to logic (higher effective power, lower output impedance, etc) so tbh it shouldn't be a surprise. The SE topology on most class D amps shows they will be worse because SE usually has to have AC coupling / DC blocking caps - 470uF electrolytic iirc for TI TPA325x - in the signal path when BTL doesn't.

I have a 2.1 fda amp and an exact same model with 2.0. The 2.0 definitely sounds better but the 2.1 is still fine for its purpose where 2.1 is needed.
__________________

Last edited by Nanoloop; 14th February 2018 at 10:48 AM.
  Reply With Quote
Old 14th February 2018, 10:50 AM   #546
robinlawrie is offline robinlawrie  United Kingdom
diyAudio Member
 
Join Date: Feb 2008
ok well i wish someone had pointed that out to me during the lengthy discussions i had here about the best configuration for my amp :P

ahh well since i can get (according to the datasheet) 77w @4 ohms with 1%thd, (more than my speakers can handle) and i doubt if i can hear the difference between 100db snr and 112 db snr, probably i shouldnt worry too much .
  Reply With Quote
Old 14th February 2018, 11:11 AM   #547
Nanoloop is offline Nanoloop  Hong Kong
diyAudio Member
 
Join Date: Feb 2013
Location: Beyond Infinity
Exactly. They're fantastic amps and what matters more is speakers/room cos this create far more distortion and frequency response issues which are more audible.
__________________
  Reply With Quote
Old 16th February 2018, 06:12 PM   #548
selwe is offline selwe
diyAudio Member
 
Join Date: May 2016
Location: Romania
I've red about hobbyhifiladen.de in this thread.What is wrong with these guys.
I've ordered and payed for two days. I send them an email and also used the contact form on their website. NOBODY is answering.
  Reply With Quote
Old 17th February 2018, 08:52 AM   #549
selwe is offline selwe
diyAudio Member
 
Join Date: May 2016
Location: Romania
Quote:
Originally Posted by selwe View Post
I've red about hobbyhifiladen.de in this thread.What is wrong with these guys.
I've ordered and payed for two days. I send them an email and also used the contact form on their website. NOBODY is answering.
Got some answers here (if this also concerns you):
Sure Electronics AA-AB32313 2x400
Sure Electronics AA-AB32313 2x400
  Reply With Quote
Old 17th February 2018, 08:52 AM   #550
wealas is offline wealas
diyAudio Member
 
Join Date: Apr 2017
Monday and Tuesday were kind of holidays in Germany so they might have taken some days off.

Edit: guess not the case...
  Reply With Quote

Reply


TI TPA3255EVMHide 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
TPA3255EVM to complete amp (advise needed) VerticalEaz Class D 67 15th January 2018 03:05 AM
tpa3255evm spacesaver mod robinlawrie Class D 84 12th December 2017 07:20 AM


New To Site? Need Help?

All times are GMT. The time now is 05:21 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki