Lepai T-Amp with TA2020 - Page 99 - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 28th November 2011, 09:21 AM   #981
htgeek is offline htgeek  United States
diyAudio Member
 
Join Date: Aug 2004
Location: House
Quote:
Originally Posted by actinium View Post
care to share what inductors you replaced with and how u replaced them??
Same question here.

It seems that everybody replaces them with toroidal 10uH 3A inductors, but don't know if exists any other requirement, as I see that there are inductors with more features (choke frequency, etc.)…

I have seen these on ebay http://www.ebay.es/itm/260894512078 and http://www.ebay.es/itm/260512722675 The first look nicer, but the second is cheaper, more inductors, and more amps capable…

Any recommendations here?
  Reply With Quote
Old 28th November 2011, 09:24 AM   #982
frasco is offline frasco  Finland
diyAudio Member
 
Join Date: Nov 2011
Location: Finland
I have the second ones. Haven't built my amp yet and don't have anything to compare with for that matter, so no recommendations sorry..
  Reply With Quote
Old 28th November 2011, 09:38 AM   #983
diyAudio Member
 
Calamaro's Avatar
 
Join Date: Mar 2008
Location: Twenty Thousand Leagues Under the Sea
Tripath definitely suggests toroidal inductors with iron-powder cores as shielded bobbin construction is not as effective for EMI containment.
Powdered iron is regarded to have an higher Q and in our case this is a premium.

http://www.osoelectronics.com/downlo...%20Toroids.pdf

For the smallest toroid suggested by Tripath, Micrometals code is T60-2. This is the toroid provided by 41Hz.com with their kits and require 39 turns of 0.5mm magnet wire; I think Arjien Helder too use them: try to count the turns

(A bigger one -with better specs- could be "T68-2 wound with 44 turns of 22AWG wire" according to Tripath technical informations).

Anyway, we need

10mH
3A
frequency higher than 1 MHZ
coil with high Q and
low saturation at high frequency

Your first option is definitely very good (the one from HelderHifi).

ps. how nice to see this thread still alive... a couple of years ago I had fun and really enjoyed this little amazing amp bypassing op amp and tone control but it seems that pcb now is a different one

Lepai T-Amp with TA2020

Lepai T-Amp with TA2020

Last edited by Calamaro; 28th November 2011 at 09:59 AM.
  Reply With Quote
Old 28th November 2011, 11:55 AM   #984
frasco is offline frasco  Finland
diyAudio Member
 
Join Date: Nov 2011
Location: Finland
First link doesn't work.

edit: You meant this one? http://oldradios.co.nz/downloads/Win...%20Toroids.pdf

Last edited by frasco; 28th November 2011 at 11:57 AM.
  Reply With Quote
Old 28th November 2011, 12:00 PM   #985
diyAudio Member
 
Calamaro's Avatar
 
Join Date: Mar 2008
Location: Twenty Thousand Leagues Under the Sea
Sorry, it was an old link and I didn't check it
Yes this is the paper

http://oldradios.co.nz/downloads/Win...%20Toroids.pdf

Last edited by Calamaro; 28th November 2011 at 12:22 PM.
  Reply With Quote
Old 29th November 2011, 05:52 PM   #986
diyAudio Member
 
Join Date: Aug 2011
Quote:
Originally Posted by actinium View Post
care to share what inductors you replaced with and how u replaced them??
Hello sorry for the late awsner.

I replaced with TDK SLF12565T-100M4R8 that I had already purchased. They are classified as power inductors but they did a great job on replacing the Lepai ones. 20 inductors for 10 bucks on ebay. Digi key sells one for 2.13. I can't tell you the frequency of those because I was unable to find that info:

Cheap
10uH
Rated 4.8a
shielded

They are much better than the lepai stock but chokes with iron powder cores like the already mentioned t60-2 might be better since they are suggested by tripath and used on their reference boards.

After alot of reading on the subject I think it is up to your taste as you can see here . After testing all the recommended and suitable types this guy went for the non obvious option.

[]'s
  Reply With Quote
Old 29th November 2011, 06:02 PM   #987
htgeek is offline htgeek  United States
diyAudio Member
 
Join Date: Aug 2004
Location: House
Quote:
Originally Posted by Calamaro View Post
Tripath definitely suggests toroidal inductors with iron-powder cores as shielded bobbin construction is not as effective for EMI containment.
Powdered iron is regarded to have an higher Q and in our case this is a premium.

http://www.osoelectronics.com/downlo...%20Toroids.pdf

For the smallest toroid suggested by Tripath, Micrometals code is T60-2. This is the toroid provided by 41Hz.com with their kits and require 39 turns of 0.5mm magnet wire; I think Arjien Helder too use them: try to count the turns

(A bigger one -with better specs- could be "T68-2 wound with 44 turns of 22AWG wire" according to Tripath technical informations).

Anyway, we need

10mH
3A
frequency higher than 1 MHZ
coil with high Q and
low saturation at high frequency

Your first option is definitely very good (the one from HelderHifi).

ps. how nice to see this thread still alive... a couple of years ago I had fun and really enjoyed this little amazing amp bypassing op amp and tone control but it seems that pcb now is a different one

Lepai T-Amp with TA2020

Lepai T-Amp with TA2020
Thanks a lot, very interesting the link about toroids.

I will buy them and give a try... (I will end spending more money in improvements than the cost of the amplifier XD).

I think that with this mod, bypass tone, changing decoupling capacitors and a bigger power input capacitor will be enough, or at least I hope so...
  Reply With Quote
Old 29th November 2011, 08:20 PM   #988
frasco is offline frasco  Finland
diyAudio Member
 
Join Date: Nov 2011
Location: Finland
Btw here's an interesting little study on inductor placement: http://www.troelsgravesen.dk/coils.htm
  Reply With Quote
Old 30th November 2011, 10:04 AM   #989
diyAudio Member
 
Calamaro's Avatar
 
Join Date: Mar 2008
Location: Twenty Thousand Leagues Under the Sea
Quote:
Originally Posted by htgeek View Post
Thanks a lot, very interesting the link about toroids.

I will buy them and give a try... (I will end spending more money in improvements than the cost of the amplifier XD).

I think that with this mod, bypass tone, changing decoupling capacitors and a bigger power input capacitor will be enough, or at least I hope so...
I agree, this will be definitely enough for this pcb. Honestly speaking if you want more choose a better pcb. Maybe you could replace the volume pot with a better one.

PS. please keep in mind that the best improvement will come just from listening to the amp: it need 100 hours burning.

Last edited by Calamaro; 30th November 2011 at 10:18 AM.
  Reply With Quote
Old 30th November 2011, 06:56 PM   #990
st33n is offline st33n  Netherlands
diyAudio Member
 
Join Date: Aug 2011
I keep getting a "humm" on my amp. It a Helder TA2020mk3. Any tips? Not sure how to ground it or anything..
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
New ta2020 pcb'S ArjenShenzhen Vendor's Bazaar 98 14th November 2012 11:39 AM
Ta2020 Bengali Class D 0 29th September 2007 05:28 AM
Eb-ta2020 opentop Class D 16 30th May 2005 07:42 AM


New To Site? Need Help?

All times are GMT. The time now is 09:56 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2