Group order of non-inverted LM4780 pc boards? Anyone interested? - Page 12 - diyAudio
Go Back   Home > Forums > Commercial Sector > Group Buys

Group Buys Members group buys

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 20th May 2004, 06:05 PM   #111
diyAudio Member
 
Join Date: Jun 2003
Location: Netherlands
Hi,

I emailed BrianGT about this already, but maybe some other people here can give their opinion on this too

For a first time (chip-)amp I would like to build one of the kits BrianGT distributes. They will be driving my 87dB diy speakers.
What would you choose, being most educational and foolproof ? This new 4780 kit or the 3875 kit?

I do have some soldering experience and recently built my own speakers, but no experience whatsoever on amps yet.

Thanks Razorfist
  Reply With Quote
Old 20th May 2004, 06:17 PM   #112
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
Quote:
Originally posted by Razorfist
I emailed BrianGT about this already, but maybe some other people here can give their opinion on this too

For a first time (chip-)amp I would like to build one of the kits BrianGT distributes. They will be driving my 87dB diy speakers.
What would you choose, being most educational and foolproof ? This new 4780 kit or the 3875 kit?

I do have some soldering experience and recently built my own speakers, but no experience whatsoever on amps yet.
Let me reiterate my response here for others. I am using the LM3875 gainclone amplifier with my < 90 dB efficient Seas Thor TL speakers (I think they are around 87dB), and I get plenty of power with them. I can turn it up to the point where it makes my ears hurt, without the amplifier clipping. (320VA 2x24vac transformer) It is also a much more proven design than the LM4780. The only hard part about the kit is creating a chassis, and wiring up the power supply (be careful with the AC). I have a manual for the LM3875 kit on my website:
http://www.BrianGT.com (I will add more to it someday when I am not busy)

I also haven't built a LM4780 amplifier yet, and am ordering prototypes soon to try it out, before doing a large order of pcbs.

It will be a month or so before the LM4780 kits start shipping out, since it will take a week to get prototype boards made, some time to test it, then another week to get production boards made.

My intention for the LM4780 is to drive the bottom end of an active crossover system, as this will allow me to use a more inefficient woofer and still match my mids and tweeter.

--
Brian
  Reply With Quote
Old 21st May 2004, 05:11 PM   #113
diyAudio Member
 
Join Date: Jun 2003
Location: Netherlands
Thanks for the reply!

First I'm gonna subscribe to paypal and in the meantime wait for your experience on the new kit.
  Reply With Quote
Old 22nd May 2004, 07:18 PM   #114
diyAudio Member
 
Join Date: May 2002
Default Fake Class A idea

Being a not too technical newbie, Neutron7's thoughts on this topic seemed interesting. Can someone reply?

I presume another advantage of this would be faster transient response as it should double the slew rate. Is this correct?

Thanks!
  Reply With Quote
Old 24th May 2004, 12:58 PM   #115
Alcaid is offline Alcaid  Norway
diyAudio Member
 
Alcaid's Avatar
 
Join Date: Nov 2003
Location: Klepp
So, what's the current status on the LM4780 PCB? Have you implemented the Zobels?
  Reply With Quote
Old 26th May 2004, 01:48 AM   #116
diyAudio Member
 
Join Date: Dec 2001
Location: SIUE, Illinois, USA
about the zobels and ect...

every feature requires you place components and then route stuff. granted the board uses 2 sides but doesn't use ALL of both sides...

adding components beyond the caps will prevent clamp-mounting.

this board appears to be a minimalist board -- there are no 10uf or 0.1uf bypass caps, and no zobels.

also, can you phycially move a zobel and maintain good effectiveness? if you move the zobels too far, wouldn't you just defeat the purpose of them becuase there would be too much inductance.
__________________
if only it could be used for good, not evil...
  Reply With Quote
Old 26th May 2004, 01:50 AM   #117
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
What do you mean by clamp mounting? Since this board is minimalist approach, the size is also minimal, you can't move Zobel too far
__________________
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 26th May 2004, 02:09 AM   #118
diyAudio Member
 
Join Date: Feb 2004
Location: Racine, Wisconsin
I thought this was a Zobel free zone?
  Reply With Quote
Old 26th May 2004, 02:29 AM   #119
SQ Kid is offline SQ Kid  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
Send a message via AIM to SQ Kid Send a message via MSN to SQ Kid Send a message via Yahoo to SQ Kid
hey, i'd be interested in 2 sets. building the parent's a home theater setup for their anniversary, and i have yet to get a sub/amp setup yet. this sounds like it would work (of course they'd be getting my old kenwood combo, this might be too much for them and i want a new sub )
  Reply With Quote
Old 26th May 2004, 12:48 PM   #120
diyAudio Member
 
Join Date: Jul 2002
Location: Netherlands
Send a message via MSN to Tazzy
Think I'm interested in pcbs for 4 channels
  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



New To Site? Need Help?

All times are GMT. The time now is 10:19 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