Goodbye Mr Chips... - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 16th May 2005, 05:00 PM   #1
diyAudio Member
 
Join Date: May 2005
Location: Birmingham or York, UK
Angry Goodbye Mr Chips...

Hello to everyone, this is my first post

Unfortunately it brings some sad news....and it was all going so well.....

I got a lovely 4780 kit from Peter Daniel and set about making a small stereo amp as my first ever DIY project.

Having spent the past few days putting the kit together, it was ready for testing today. Well, it worked.....first time. I was well chuffed and then whilst checking the voltages on one of the boards i must have shorted the rails with a probe lead....my stereo has become a mono ! So frustrating! Guess i'll just have to get hold of another chip....other components look to be ok, so with any luck i can swap the chip out and all will be well.

Whilst I've got all of your attention, I might as well ask...At the moment I have no power switch and sometimes, when plugging in, the 1.6A time delay fuses I'm using blow. Sometimes they don't however...

Using a 300VA Transformer with 25V twin secondaries.

Anyone shed any light on this? Is it just to do with current inrush at power on (i.e. do i need some bigger/longer time delay fuses)? I'm not using any Ci caps or input caps at the mo.
  Reply With Quote
Old 16th May 2005, 05:08 PM   #2
Gasho is offline Gasho  Croatia
diyAudio Member
 
Gasho's Avatar
 
Join Date: Nov 2004
Location: Zagreb
Try a 2A slow blow fuses , and next time be more carefull while you measuring voltages. Use hook-up clips on your intrument probes and fix them on element legs before powering up the amp.
  Reply With Quote
Old 17th May 2005, 10:50 AM   #3
diyAudio Member
 
Join Date: May 2005
Location: Birmingham or York, UK
Many thanks for the reply. It was my own silly fault...standard safe procedure went out the window in a flurry of excitement

Peter Daniel: How much to get a replacement lm4780 from you with shipping to the UK? I'm gonna be stung by big handling fees etc to order in the UK.

If anyone is putting in a Farnell/Digikey order and could help me out here I'd be eternally grateful.
  Reply With Quote
Old 17th May 2005, 12:52 PM   #4
diyAudio Member
 
Join Date: May 2005
Location: Birmingham or York, UK
£20 minimum order if I'm not mistaken.....
  Reply With Quote
Old 17th May 2005, 12:59 PM   #5
Gasho is offline Gasho  Croatia
diyAudio Member
 
Gasho's Avatar
 
Join Date: Nov 2004
Location: Zagreb
Why don´t you buy this chip at local electronic shop , or from Farnell??
  Reply With Quote
Old 17th May 2005, 01:14 PM   #6
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally posted by Gasho
Why don´t you buy this chip at local electronic shop , or from Farnell??

LM4780's are on backorder until June. I talked with National a few weeks ago -- they are really ramping production -- but the chips is unobtainium for few weeks more.
  Reply With Quote
Old 17th May 2005, 01:19 PM   #7
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Rich, drop me a line, I have a spare!
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 17th May 2005, 02:16 PM   #8
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
Quote:
Originally posted by richgraham
Peter Daniel: How much to get a replacement lm4780 from you with shipping to the UK? I'm gonna be stung by big handling fees etc to order in the UK.
I can send it to you for $10, shipping included. But try pinkmouse offer first.
__________________
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 17th May 2005, 02:47 PM   #9
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Sofia
Quote:
my stereo has become a mono ! So frustrating!
But on the bright side you have the opportunity to become a Sakuma-san of the chip amps.
  Reply With Quote
Old 17th May 2005, 03:07 PM   #10
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
Quote:
my stereo has become a mono ! So frustrating!
You can still wire a single LM4870 chip for a stereo operation

Just separate the inputs, add one more 22k shunt resistor and pick up both outputs before 0.1 R resistors (lifting their other ends from the board). You might even like it more than a parallel version
__________________
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

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
Hello and Goodbye for a bit justblair Introductions 1 10th April 2009 02:28 AM
Any 24 bit NOS DAC chips? neutron7 Digital Source 6 29th October 2006 09:48 AM
Goodbye Yellow Brick Road ThorstenL Everything Else 7 26th July 2006 04:42 AM
Chips for Chumps aka "Intelligent Chips" jackinnj Solid State 0 15th April 2005 01:37 AM


New To Site? Need Help?

All times are GMT. The time now is 11:08 PM.


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