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

8-Channel Gainclone Amplifier
8-Channel Gainclone Amplifier
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 8th May 2012, 11:17 AM   #11
gainphile is offline gainphile  Australia
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
Here you can see 160VA, 25v-0-25v Toroidal transformer that I use.

Click the image to open in full size.

Initially I was just trying it and planned for a bigger one (300VA). However there is no problems using it driving the speakers to deafening level. It is well known that dipoles are very easy speakers to drive (e.g. the woofers operate at their inherent Fs). Hence I keep it.

The cabling could be much neater, but I prefer keeping them long, in case another swap with ClassD is needed

You can compare the look with ClassD:

Click the image to open in full size.
__________________
http://gainphile.blogspot.com
  Reply With Quote
Old 8th May 2012, 11:29 AM   #12
gainphile is offline gainphile  Australia
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
This is a very good album to ensure maximum current flowing out of those chipamps

Click the image to open in full size.

At neighbour-engaging levels, the gainclones stabilises at "4-second touch" heat. Pretty hot, but does not seem hot enough to trip their thermal protection

The 4x H-frame dipole woofers are equalised to 20hz, Q=0.707.
__________________
http://gainphile.blogspot.com
  Reply With Quote
Old 12th May 2012, 09:39 PM   #13
gainphile is offline gainphile  Australia
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
I noticed the noise / hiss of these amps are higher than my classD, which is surprising. Note that I am using waveguides on the Tweeters which raises the sensitivity to additional +6db to +10db too. The gain might bee to high too on the gainclone.

The hiss can be reduced by applying decoupling caps on the chips (100nF) and the PSU's AC inputs (120nF)

Click the image to open in full size.

Click the image to open in full size.
__________________
http://gainphile.blogspot.com
  Reply With Quote
Old 13th May 2012, 09:48 AM   #14
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Have you measured the noise on the output?
Have you checked to see if the PSU is ringing/oscillating?
Have you checked to see if the amplifier is ringing/oscillating?
__________________
regards Andrew T.
Sent from my desktop computer using a keyboard
  Reply With Quote
Old 15th May 2012, 11:21 PM   #15
gainphile is offline gainphile  Australia
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
No, I do not have oscilloscopes.

The behaviour of the amps seems like a stable one. Not hot etc. The hiss is audible from 1m which is too much for my liking.

I could reduce this further by lowering the amp's gain, or implementing LPAD to the tweeters. So not really a drama. The tweeter's sensitivity had been increased due to waveguide.
__________________
http://gainphile.blogspot.com
  Reply With Quote
Old 16th May 2012, 05:52 AM   #16
avbuilder is offline avbuilder
diyAudio Member
 
Join Date: Nov 2009
Probably a grounding issue. Have you used star grounding.
  Reply With Quote
Old 16th May 2012, 09:31 AM   #17
volume knob is offline volume knob  New Zealand
diyAudio Member
 
volume knob's Avatar
 
Join Date: Dec 2011
Location: North Shore
Quote:
Originally Posted by gainphile View Post
I noticed the noise / hiss of these amps are higher than my classD,
Have you checked your pre-amp and/or sources for the hiss?, It could be that the low pass filter in the output of the class D amp could help filter out any hiss, where as with the class ab amps the hiss could pass straight though
  Reply With Quote
Old 1st June 2012, 07:31 PM   #18
cuibono is offline cuibono  United States
diyAudio Member
 
cuibono's Avatar
 
Join Date: May 2006
Location: City of Angles
Hey Andi, nice looking speakers. I came across this thread because I'm having the same problem as you (although with a different cause, I'm sure). My 4 way dipoles also have an audible hiss, which after living with for a number of months, has to go.

For me, the noise is coming from my miniDSP unit (which I think you're also using). My problem is that I need my volume control to be after the miniDSP, not before it. What do you use?

I like your amp setup. I built 8 channels of custom amps, point to point, and it is way too big, way too complicated, expensive, and way more power than I need. I really should have gone with GC amps...
  Reply With Quote
Old 1st June 2012, 08:19 PM   #19
mattmcl is offline mattmcl  United States
diyAudio Member
 
Join Date: Apr 2009
Location: Erie, CO
Just curious, are those Seas drivers?
  Reply With Quote
Old 3rd June 2012, 05:42 AM   #20
kuldeepsingh is offline kuldeepsingh  India
diyAudio Member
 
kuldeepsingh's Avatar
 
Join Date: Aug 2006
Location: Chennai, India
Send a message via MSN to kuldeepsingh
the temperature of the heatsink looks high '4 sec finger touch' . It looks quite small for 8 channel amplifier. I used 2 heatsinks for a similar setup but still they run hot ' say 12 sec finder touch'.
Attached Images
File Type: jpg DSC02747.JPG (101.2 KB, 446 views)
__________________
. . .. ... ..... ........ ............. ..................... ..................................
My Blog

Last edited by kuldeepsingh; 3rd June 2012 at 05:59 AM.
  Reply With Quote

Reply


8-Channel Gainclone AmplifierHide 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
5 + 2 (bridge) channel gainclone pra3718 Chip Amps 39 31st May 2013 11:24 AM
Building a 5 channel GainClone Kevinwil Chip Amps 6 5th January 2007 04:03 AM
Gainclone has 1/8-1/4 the volume one channel Jimmy154 Chip Amps 15 25th June 2006 05:21 PM
Newbie wants to build a "GainClone-Like" 5.1 Channel Battery Powered Amplifier captain Chip Amps 7 15th October 2004 12:35 PM
3-channel gainclone for multimedia? trespasser_guy Chip Amps 2 16th May 2003 05:10 PM


New To Site? Need Help?

All times are GMT. The time now is 08:17 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki