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

Chip Amps Amplifiers based on integrated circuits

TDA7293 board from China
TDA7293 board from China
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 7th December 2018, 02:59 AM   #11
nigelwright7557 is offline nigelwright7557  United Kingdom
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
Be very careful altering the gain.
These chip amps have a minimum gain before they start oscillating.
I reduced one to a gain of 7 because I used it in conjunction with a valve with a gain of 8 and it just oscillated and got very hot. It wasn't until I read the datasheet again I noticed the min gain of about 22.
I couldn't change the valve gain much so put a 1000pf across chip amp + and - inputs and that calmed things down.
__________________
PCBCAD51 download or CDROM 2019 version out now http://www.murtonpikesystems.co.uk
  Reply With Quote
Old 7th December 2018, 10:47 AM   #12
chermann is offline chermann  Austria
diyAudio Member
 
Join Date: Jan 2017
Location: Vienna
Hi nick

the current for the power supply is mentoined the rating of the transformer/or SMPS
e.g.200VAC transformer with 22V and deliver 5 ampere each wounding

AS-2222 - 200VA 22V Transformer - AnTek Products Corp

if you compare with an 100VA transformer..then you will se he is abel to deliver just 2,3 amps....

Last edited by chermann; 7th December 2018 at 10:49 AM.
  Reply With Quote
Old 7th December 2018, 06:46 PM   #13
danielwritesbac is offline danielwritesbac  United States
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Quote:
Originally Posted by nick1974 View Post
did you mean 4A for each IC or for pair?
It would work either way. But, if you want more linear (including sturdy bass support), the higher amperage transformer helps (especially in getting the steady voltage needed for high quality audio).

This looks pretty good for a stereo amplifier: AS-3222 - 300VA 22V Transformer - AnTek Products Corp

For sound quality purposes, even the 400va version would be useful; however, it is very huge and that's unnecessary unless you plan to drive 4 ohm speakers.
__________________
TDA8932ClipNipperLM1875TDA7293Powerful Parallel TDA7293 kit ♦ My post has opinion.
  Reply With Quote
Old 7th December 2018, 08:23 PM   #14
nick1974 is offline nick1974
diyAudio Member
 
Join Date: Jul 2017
Quote:
Originally Posted by danielwritesbac View Post
It would work either way. But, if you want more linear (including sturdy bass support), the higher amperage transformer helps (especially in getting the steady voltage needed for high quality audio).

This looks pretty good for a stereo amplifier: AS-3222 - 300VA 22V Transformer - AnTek Products Corp

For sound quality purposes, even the 400va version would be useful; however, it is very huge and that's unnecessary unless you plan to drive 4 ohm speakers.
Daniel, thank you very much for answering.
My plan is to use those cards to make a 5.1 system in experiment of mix triode tubes and those ICs in supertriode circuit, and I will use 7 ICs, 5 for the channels and a pair for the subwoofer.
My diy speakers are 8 ohms but the sw is 2x2 ohms so I count it as a 4 ohms channel (using 2 ICs bridged)
for this system 2 transformers 1 KVA each do you think its enough?
  Reply With Quote
Old 8th December 2018, 08:46 AM   #15
danielwritesbac is offline danielwritesbac  United States
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Quote:
Originally Posted by nick1974 View Post
...4 ohms channel (using 2 ICs bridged)...
Sounds like minimized audio quality, minimized durability, quick and permanent hearing damage also resulting in quick and permanent reduction in the capacity to enjoy music. So, that's the risks. Please explain the need of it? What is the venue size? A venue much larger than a house might need that much audio; but, it would be unusual to use chip amplifiers for it.
Initially, this seems like a case of application mismatch.
And these, albeit enjoyable, are not good enough to bridge them.
Also, you might like to know that more quality can do a similar level of enjoyment at less damaging output levels. So, perhaps, re-aim.
__________________
TDA8932ClipNipperLM1875TDA7293Powerful Parallel TDA7293 kit ♦ My post has opinion.

Last edited by danielwritesbac; 8th December 2018 at 09:03 AM.
  Reply With Quote
Old 10th December 2018, 08:53 AM   #16
danielwritesbac is offline danielwritesbac  United States
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Modulus-686 | Neurochrome :: Audio
There's the highly linear 360W chip amp.
Looks like it would take a 500va transformer.
The nested feedback amplifier saves a little money there, because you don't need to upsize the transformer current capacity for linearity purposes--the linearity of a nested feedback amplifier, the master feedback loop, is run from the small signal amplifier on stabilized power, unaffected by the efforts of the 6 high current chips pushing your woofer.

Anyway, Neurochrome Modulus-686: 240W(8Ω); 360W(4Ω) @ 0.00025% THD+N that shows what it takes to do a good job driving 4 ohm load, at high power, with chips. For the subwoofer task, we didn't actually need the super-low distortion figures; but, the linearity of it, is necessary for accuracy.

That accuracy avoids bass monotony, by simply preserving the uniqueness of audio tracks (it has clean bass, excellent specs, no sonic signature of its own).
__________________
TDA8932ClipNipperLM1875TDA7293Powerful Parallel TDA7293 kit ♦ My post has opinion.
  Reply With Quote

Reply


TDA7293 board from ChinaHide 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
tda7293 amp board what tranformer for 6ohm /80w mono spk thesaintxxx Chip Amps 3 31st October 2018 08:09 AM
TDA7293 2.1 Power amplifier board aleks990 Chip Amps 7 15th September 2018 04:00 PM
Newbie TDA7293 Parallel Build Board Layout CakeorDeath Chip Amps 7 8th May 2017 05:16 PM
Which power supply for a TDA7293 board? Coliban Power Supplies 3 3rd February 2016 12:07 PM
My GIFT for you: TDA7293 board + extras -_nando-_ Chip Amps 12 22nd April 2013 09:08 PM


New To Site? Need Help?

All times are GMT. The time now is 12:11 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki