Basic Mixer Design: need input - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

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 28th May 2010, 01:14 AM   #1
dcsimon is offline dcsimon  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Atlanta, GA
Default Basic Mixer Design: need input

After a little research I've worked up a rough plan for a simple 10x2 mixer with 3 aux sends, the schematic bellow is just for a single channel strip, my plan is to use inverting virtual earth gain stages for each summing buss (master and auxes). Any input would be much appreciated (especially on the panning section). You can ignore the INA127 section. P1 is an insert return, K2 is for tape return, R14 and R15 feed the left and right mix buss respectively.
Attached Images
File Type: png Mixer.png (44.1 KB, 200 views)
  Reply With Quote
Old 28th May 2010, 01:31 AM   #2
diyAudio Member
 
Join Date: May 2001
Location: Bangalore, India
I am not able to enlarge the schematic posted. Check Rod Elliot's mixer design as well as some Sound Craft schematics available on the web.
__________________
Sam
  Reply With Quote
Old 28th May 2010, 01:41 AM   #3
dcsimon is offline dcsimon  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Atlanta, GA
Awesome, Rod Eliott's stuff is very helpful, Here is a pdf, maybe that will work better as an attachment.
Attached Files
File Type: pdf mixer.pdf (46.7 KB, 123 views)
  Reply With Quote
Old 28th May 2010, 04:18 PM   #4
diyAudio Member
 
Join Date: Nov 2008
Just a few comments/questions:
-U2A pin 3 is not protected
-What are SW2-4 supposed to do?
-P1 and P2 go where?
-For clarity, do not cross parts and wire connections (primarily in your mic. input section). It makes the head hurt!
E
  Reply With Quote
Old 28th May 2010, 05:06 PM   #5
dcsimon is offline dcsimon  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Atlanta, GA
Should pins 2 and 3 of K2 be coupled through some caps for protection?.

P2 is an insert send to, p1 is the insert return, when nothing is inserted between the pre and aux section p2 and p1 are connected together. sw2-4 allow for the aux sends to be switched between the mic pre/channel path and the line in tape return (this mixer is designed for monitoring during the recording process).

What is the advantage to using the triple op-amp design from Rod Elliot:
http://sound.westhost.com/p30a_f4.gif
  Reply With Quote
Old 30th May 2010, 12:38 PM   #6
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
Default DC blocking and DC source

I found my op amp mixer (herald RA-88A) completely unable to cope with the DC offset of my quasi-sine wave generator, due to lack of blocking capacitors on inputs. Whereas my PAS2 preamp with 12AX7 tubes had no problem with it. Cost me a day of head scratching to find that DC bias on the home built source was the problem, not bad repair on the mixer. Most band mixers intentionally put DC on the inputs at the command of a switch, to power "phantom power" microphones. I find modern 5 or 10 uf 50V ceramic capacitors less worrisome than the traditional electrolytics in this location, although at $5 each they are a bit premium.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300
  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
Basic Input Impedance Questions luvdunhill Solid State 10 20th November 2007 12:46 AM
Motorcycle Intercom Input Mixer w/Override HiOSilver Chip Amps 4 30th September 2006 11:19 AM
Lm1036 Basic input questions Papageoff Chip Amps 1 4th November 2004 02:18 AM
build basic audio mixer (4 channels to 1)? janklug Analogue Source 10 28th October 2004 01:04 PM
basic audio mixer (4 channels to 1)? janklug Digital Source 2 29th September 2004 05:51 PM


New To Site? Need Help?

All times are GMT. The time now is 09:55 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