Commercial Gainclone kit- building instructions - Page 166 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Audio Sector

Audio Sector Kits & PC boards from AudioSector

Reply
 
Thread Tools Search this Thread
Old 9th May 2013, 12:02 PM   #1651
glenv6 is offline glenv6  United States
diyAudio Member
 
Join Date: Nov 2011
Quote:
Originally Posted by Lightman View Post
If the LM3875 kit is built correctly, you shouldn't need a slow start circuit. If you "borrowed heavily from that design," what did you do different? Was it only the physical layout, or did you make any circuit changes from the kit specs?
I was referring to the physical layout with only one exception. I used one ground wire between PG on the rectifier board and the star ground point at the amps. I tied PG together on the rectifier board using 14ga solid core wire and soldered that single ground wire to the middle of that.

I turned the amp on and off many times and listed to it for hours before this happened. Looking my project over, I can't see anything I did wrong. It just seems like that huge toroidal transformer just surged when I turned it on that last time. It is a brand new transformer. Is it possible that the transformer is defective?

Any idea what could have been damaged? Should the caps and resistors be okay? My thought is to replace just the LM3875s and try again...
  Reply With Quote
Old 9th May 2013, 12:05 PM   #1652
glenv6 is offline glenv6  United States
diyAudio Member
 
Join Date: Nov 2011
Quote:
Originally Posted by AndrewT View Post
Beginners should never omit the "optional" stability and filtering components.
How about some detail. Which ones, and what would they have done to prevent this?
  Reply With Quote
Old 10th May 2013, 11:25 AM   #1653
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by glenv6 View Post
I turned the amp on and off many times and listed to it for hours before this happened. Looking my project over, I can't see anything I did wrong. It just seems like that huge toroidal transformer just surged when I turned it on that last time. It is a brand new transformer. Is it possible that the transformer is defective?
You can measure the transformer's output, to see if it is functioning correctly, and measure the output of the rectifier board.

When you first assembled the amp, did you measure it's DC offset?
  Reply With Quote
Old 10th May 2013, 11:11 PM   #1654
glenv6 is offline glenv6  United States
diyAudio Member
 
Join Date: Nov 2011
Quote:
Originally Posted by Lightman View Post
You can measure the transformer's output, to see if it is functioning correctly, and measure the output of the rectifier board.

When you first assembled the amp, did you measure it's DC offset?
Hi Lightman, thanks for your reply... I measured the transformer's output on both sides AC and DC before I hooked it up to the amplifier for the first time. The voltages were matched and stable. I did not check the DC offset when I powered the amp up for the first time. I went straight to the speakers and supplied an input signal using an old Microsoft Zune I had laying around. The amp sounded great and I was very pleased! What did you have in mind with the DC offset?

The problem happened the next day after I moved the mains plug from the variac to a power strip and switched on the power supply with the amp hooked up. I assume the amp was working properly until then as it was quiet, cool, and sounded clear and good.

AndrewT suggested I use filters, so I explored this site a little more and found Nuuk's excellent article edited by AndrewT here: Building a Gainclone chip amp power supply.. My plan now is to add that "safety earth connection" circuit to the PSU, fuse the DC side and add the 10uf caps that came with the kit. I have new LM3875TFs on order for the amp, so I'll replace those and try again.

Thanks! -Glen
  Reply With Quote
Old 14th May 2013, 03:06 AM   #1655
glenv6 is offline glenv6  United States
diyAudio Member
 
Join Date: Nov 2011
Default My Gainclone is alive and well!

Thanks to all the help on this forum, my gainclone is fixed. Turns out the amp was actually fine, it was the speakers that blew. The power supply was also fine, but it is now in an enclosure with proper grounds and it is quiet when turned on and off - no audible hums from the toroidal or pops in the speakers. Speaking of which, with a different set of speakers the amp sounds good again.

These new speakers are 4 ohm and the amp is running a little warm. I am hoping the amp runs cooler when I go to the 8 ohm full range speakers I am building.

Thanks again for the guidance.

-Glen
Attached Images
File Type: jpg 20130513_211029.jpg (983.6 KB, 322 views)
  Reply With Quote
Old 23rd June 2013, 05:01 AM   #1656
diyAudio Member
 
Join Date: Jun 2013
Default ebay?

hello Peter
thanks for the nice thread..
i'd like to build an amp prefer on your LM3875 Premium Kit , did You sell it on ebay? please inform me,
many Thank
  Reply With Quote
Old 28th June 2013, 03:18 PM   #1657
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
I do not sell on ebay, only directly from my website.
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 30th June 2013, 05:55 PM   #1658
diyAudio Member
 
Join Date: Jun 2013
Even though I can't find any good quality component in my town, i decide to make my first gainclone... and yes it is good indeed the gainclone... thanks for this thread..
  Reply With Quote
Old 19th August 2013, 09:41 PM   #1659
diyAudio Member
 
Join Date: Aug 2012
Smile Larger psu caps, where to fit?

I'm currently using the premium lm3876 kit on a plywood test board so I can try out different set up's before making an enclosure to suit. Currently I have the kit set us as standard (1500uf on amp, no PSU caps). I would like to try 3x 3300uf per rail, I have these soldered together so that only 2 legs need to fit through the PSU PCB. I don't know though if its OK to make it fit in the small pcb hole, or if there are alternative cap holes I can use. Any advice if its OK to use this capacitance and also how to fit greatly appreciated.
Cheers Andy
  Reply With Quote
Old 19th August 2013, 09:43 PM   #1660
diyAudio Member
 
Join Date: Aug 2012
Hi I just wanted to clarify that I mean do the caps have to fit in the PSU holes meant for the low value caps supplied. I realise that my message was a bit unclear.
  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
Commercial complete Gainclone kit for a beginner? gychang Chip Amps 365 4th October 2011 08:19 AM


New To Site? Need Help?

All times are GMT. The time now is 12:03 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