universal chip pre-amp project - Page 2 - 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 23rd June 2009, 10:37 PM   #11
diyAudio Member
 
Join Date: Apr 2003
Location: Seattle
Digi,

You might want to look at the Pimeta and PPA amps on tangentsoft.net, and then remove the dedicated ground channel. They're both basically the same thing -- OPamp gainstage followed by a buffer. Tangent/Phil have a lot of good info on the site regarding the headphone amps built with the nested feedback loops (I think it's mostly from Walt Jung).

That said, I think it would be nice to have the following:

1) Onboard power regulators with the option to use both dual secondaries (like a gainclone) or a center tapped (by leaving some diodes out). Maybe even something so you could have two "dual mono" preamps on the same board? LM317/337s would be fine, but discrete regulators would be nice if.

2) Spots for different sized potentiometers.. Alps RK27 and RK097?

3) Pads for SMD and DIP chips (this is pretty easy).
  Reply With Quote
Old 23rd June 2009, 10:42 PM   #12
diyAudio Member
 
Join Date: Apr 2006
Location: Minnesota
digi01,

Please use CAPS where appropriate. (I'm sorry, but i couldn't help it. I see way too much of this.)

Rick
  Reply With Quote
Old 24th June 2009, 01:34 AM   #13
Atilla is offline Atilla  Norway
diyAudio Member
 
Join Date: Jul 2008
Motherone, I was thinking of using Tangent's setup for a preamp, that's why I raised the question above. digi01 seems to have a reason to follow that design though. While a more detailed explanation (I'm fairly noobish so forgive me, please) would help, digi01, an experiment would be of the biggest benefit, at any rate.
  Reply With Quote
Old 24th June 2009, 02:27 AM   #14
digi01 is offline digi01  China
diyAudio Member
 
digi01's Avatar
 
Join Date: Mar 2003
Location: BEIJING
Send a message via MSN to digi01
to lgreen,motherone,
cause this is a pre-amp design,it is very different from headphone amp.
for a pre-amp,the before connections will be kinds of source(cd player,pc auduio interface,mp3,ipod),the voltage level is around 0.7V to 2V.the after connections will be kinds of resistance load(cables,pots).i assume the pre-amp will driver a long cable end with one fix resistor.
the headphone amp is inductance load,it is more complicated than pre-amp.the Pimeta and PPA amps is headphone amp,i admire they designer i hope i can design headamp after some days.


so,i think the most important thing of pre-amp is impedance matching,the second important thing is drive ability.that is why we use pre-amp in audio gear.950ohm link is a better value for pre-amp.sure 100ohm will works.
i agreed onboard,it is diy friendly but i do not like onboard psu for gain stage device.there are so many noise issue,trust me.you can check brand audio,factory evaluation board.no one use it.the gain stage at least far away from psu 120mm.
pots on the board is a good way to reduction signal route.i will consider it.but this is pre-amp balanced & unbalanced design.on board pot will no use for the balance setting.
smd&pdip combine footprint is good.the below is a test layout.

to sawreyrw,
yeah,i am working on it.

Zang
Attached Images
File Type: gif ucp_silk+top.gif (15.2 KB, 2314 views)
  Reply With Quote
Old 24th June 2009, 02:29 AM   #15
digi01 is offline digi01  China
diyAudio Member
 
digi01's Avatar
 
Join Date: Mar 2003
Location: BEIJING
Send a message via MSN to digi01
pic
Attached Images
File Type: gif ucp_silk+bottom.gif (13.4 KB, 2229 views)
  Reply With Quote
Old 24th June 2009, 04:02 AM   #16
digi01 is offline digi01  China
diyAudio Member
 
digi01's Avatar
 
Join Date: Mar 2003
Location: BEIJING
Send a message via MSN to digi01
the below pic is the board connections,its show standard stereo and balanced setting.in balanced mode,the chip u1 for active,u2 for passive.
this pre-amp is volume pot free design.if needed can add 10k volume pot before the input or after the output.
Attached Images
File Type: gif ucp_pcb_connections.gif (24.0 KB, 2231 views)
  Reply With Quote
Old 24th June 2009, 07:53 AM   #17
digi01 is offline digi01  China
diyAudio Member
 
digi01's Avatar
 
Join Date: Mar 2003
Location: BEIJING
Send a message via MSN to digi01
the UCP is no problem to drive 2x2 LM3886 in parallel,connections below.

to Atilla,
thanks for the inform about LME49600 buffer.i have a look on its datasheet.i have a plan of another pre-amp & headphone-amp with huge current output
Attached Images
File Type: gif ucp_dr_p3886.gif (25.4 KB, 2280 views)
  Reply With Quote
Old 24th June 2009, 10:11 AM   #18
digi01 is offline digi01  China
diyAudio Member
 
digi01's Avatar
 
Join Date: Mar 2003
Location: BEIJING
Send a message via MSN to digi01
Atilla,
i made it! this ucp v2 is a after design of the nsc's classic application.i modify it for pre-amp bettter.
i just have few samplers in stock,i hope i can find some time to test this configuration.

zang
Attached Images
File Type: gif ucp_v2sch.gif (16.3 KB, 2140 views)
  Reply With Quote
Old 24th June 2009, 10:22 AM   #19
Atilla is offline Atilla  Norway
diyAudio Member
 
Join Date: Jul 2008
That should do it, more or less. You can afford to use a higher-value pot - 50k, maybe even 100k without any problems and you'll get even higher input impedance.

I'll get around to try to make a layout for what I'm planning one of those days as well. My first try to make a board layout
  Reply With Quote
Old 24th June 2009, 01:49 PM   #20
tent is offline tent  Germany
diyAudio Member
 
Join Date: May 2009
Quote:
Originally posted by digi01
Atilla,
i made it! this ucp v2 is a after design of the nsc's classic application.i modify it for pre-amp bettter.
i just have few samplers in stock,i hope i can find some time to test this configuration.

zang
sounds interesting.. would you be able to provide pcbs?

tent:wq
  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
Which Chip for first DIY project? systemerror909 Chip Amps 3 9th January 2006 05:32 AM
Project - Universal CD Controller? lgreen Car Audio 1 22nd September 2003 01:20 AM
new project - chip amp?? yuval Chip Amps 3 14th July 2003 01:47 AM
A new chip amp project JOE DIRT® Chip Amps 11 17th June 2003 02:56 PM


New To Site? Need Help?

All times are GMT. The time now is 03:10 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