Op amps help! 3x3 12v matrix mixer - 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 14th February 2011, 09:36 PM   #1
karlis is offline karlis  Canada
diyAudio Member
 
Join Date: Sep 2010
Location: East Van
Default Op amps help! 3x3 12v matrix mixer

So many op-amps, which one to choose?

Hi! I'm working on a custom line level mixer for our freestyle soundbike setup.

What I am looking for at this point I don't think is particularly
complex. It is essentially a 3x3 array mixer, that is, three channels
in, three channels out, and the in->out bus mix is fixed. (This will allow me to mix the output of our 4-mic-to-one-line-level mixer with the mp3 player output and feed it out to a few things, mostly the 2x100w class-D amp.)

It needs to run at 12v, which if I am not mistaken means 12v single side
supply op-amps. I spent an evening reading about op-amps, and there
was a huge discussion on which "sounded better", and I kinda got lost
there, I now have a list of like 30 op-amps which are talked about on the forums. Some differences are obvious, like dual or quad, 12v or 15v, etc. But there's tons of audiophile discussion about one opamp being "brighter" or "more upfront" than the other, which I suspect is gearhead nerdiness that doesn't apply to my project. Even if I read 30 datasheets and narrow it down to 10 or so that fit my specs, how to choose one? or does it even matter?

My requirements are 9-12v single side supply operation, low power, decent sound, and breadboardable (not smp). By "decent sound" I mean I'd like fair
frequency response, but it's being used outdoors, not in a studio, so
this isn't for audiophiles.

In addition to this post on diyaudio
http://www.diyaudio.com/forums/headp...rix-mixer.html
I found a great website with modular mixer circuits that I think can be
used with very slight modifications for this project.
Universal Preamp/ Mixer (Part 2)

Maybe a big op-amp matrix in the wiki would help? min voltage, max voltage, power use, frequency response, and "audiophile comments". I started such a list in the wiki under "op amps".

The real question I have though: what op amps do you recommend for this project?
  Reply With Quote
Old 14th February 2011, 10:40 PM   #2
Banned
 
Join Date: Jan 2008
Blog Entries: 2
The NE5532 is a low-cost dual audio opamp used in many professional and semi-professional mixers.

The OPA2134 is a dual opamp costing about twice that of the 5532, it is regarded as a better performer.

The LME49710 is an even better performing single opamp which costs about 4x the OPA because you have to buy 2.

Singles have better crosstalk performance, but the NE5532 is a perfectly adequate part in your application and you don't have to cry if you blow up a few experimenting.

w
  Reply With Quote
Old 15th February 2011, 10:05 PM   #3
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
You can make a fake signal ground for dual supply amps like wakibaki mentioned by taking two 5.1V zener diodes line to not-line, with suitable resistors top and bottom for the wattage. I'm using 22 ohm resistors on 5 w zeners. This is working great on 4 op amps, see the .pdf file at the end of Improving a "Disco mixer" to mid-fi performance
Most commercial mixers use 4558's, which are slow enough to not need local power supply decoupling. 5532's have a big following on here, but most suppliers I looked at had the 14 pin kind, and I was replacing 4558's DIP 8's for hiss, so I used 33078's. I've also used 4560's which seem to be the same as 33078 performancewise. People on here say 4562 is even better (low noise, fast). All the fast op amps (not 4558's) need disc caps .01 to .1 uf within an inch of the IC on the power supplies, and need about 20 pf across the feedback resistor, to avoid oscillating. After I killed the oscillation with dime caps, my 33078's or 4560's sound great. The 4558's hissed a bit, is why I replaced them, but most commercial PA and disco mixers have them in them. I paid $.60 for the 33078's from farnell.com (newark in the US).
__________________
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

Last edited by indianajo; 15th February 2011 at 10:19 PM.
  Reply With Quote
Old 19th February 2011, 12:42 PM   #4
Bonsai is online now Bonsai  Taiwan
diyAudio Member
 
Bonsai's Avatar
 
Join Date: Jul 2003
Location: Taipei, Taiwan
There is no doubt that the OPA2134 is absolutely inferior to the SA5532/34 at loads greater than 600 Ohms. Please take a look at Douglas Self's comments on this device. The OPA2134 is another op amp masquerading as an audio grade device that absolutelt does not meet the grade. Currently (February 2011), there are only 3 op-amps to be recommended for audio: SA5532/32, LM4562 and direct derivatives, AD797. Period.
__________________
bonsai
Amplifier Design and Construction for MUSIC! http://hifisonix.com/
  Reply With Quote
Old 19th February 2011, 05:12 PM   #5
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
Quote:
Originally Posted by Bonsai View Post
Currently (February 2011), there are only 3 op-amps to be recommended for audio: SA5532/32, LM4562 and direct derivatives, AD797. Period.
I'm pretty happy with predecessor NJM4560, and interchangeable ST33078. Might try 4562 someday, but I'm not breaking my neck to pay $6 shipping to find out. Listening to the 33078's right now, in fact, the PAS2 is too expensive to leave on all the time (100 watts). Little vague why everybody keeps calling it LM4562, when all the datasheets I have originate from JRC & TI, and the 1998 Peavey CS800s amp had actual NJM4560's in it. Who was first, NationalSemi or JRC? My paper catelogs stopped coming in 1980 when the Army called me back.
Besides the resistor loads of the two transistor amps, I tried the 33078 direct coupled to the grid of a 7199 tube last week (ST70). Sounds great at no load but the internal resistor in the mixer and some capacitance.
I test sound with piano records of a Steinway versus the real Steinway console located between the speakers. What to you use?
__________________
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

Last edited by indianajo; 19th February 2011 at 05:26 PM.
  Reply With Quote
Old 20th February 2011, 06:18 AM   #6
mt490 is offline mt490  Australia
diyAudio Member
 
Join Date: Jun 2010
NJM4560 and LM4562 are 8 pin dual opamps but beyond that they are not related to each other.
  Reply With Quote
Old 20th February 2011, 07:07 AM   #7
diyAudio Member
 
Join Date: Jan 2007
Quote:
Originally Posted by Bonsai View Post
Currently (February 2011), there are only 3 op-amps to be recommended for audio: SA5532/32, LM4562 and direct derivatives, AD797. Period.
In this particular application, it's about low-voltage performance. Which means the NE5532 and AD797 are out. As are the Linear Tech amps (I noticed there is no minimum supply voltage spec in the LT1028/1128 datasheet, I'm just inferring that this family will fail below 8V).

Also, the AD8599 datasheet has no spec, but some of the curves suggest operation down to 4.5V.

The LM4562 family is spec'ed at 5V, which is nice.

The TI amps (OPA2211/1612/2141 or its quad-brother the 4141) are spec'ed even more aggressively, at 4.5V.

All this surprises me a bit. I would have thought 4.5V (5V +/- 10%) audio op-amps to be a big market.

BTW, the ADI and TI parts are all SMD, but can be made "breadboardable" by using Browndog adapters (or, like a crazy friend of mine does it, DIL adapter sockets and some spare metal leads).

--
Greetz,
MatchASM

Last edited by MatchASM; 20th February 2011 at 07:22 AM. Reason: Added SMD comments
  Reply With Quote
Old 20th February 2011, 05:54 PM   #8
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
I had the 33078's operating at +-3.3 VDC for a while before I figured out there were 330 ohm resistors in the disco mixer power supply, and 33078's use more power than 4558's. They sounded fine on mag phone in and line in from CD player, nominal 1v PP(?) However, the FM radio hisses more when the output is turned down that low, so to cope with 4 V PP signals I boosted the power supply on the disco mixer to 1n5344's, or +-7.9VDC.
NJM4562 has no minimums listed on gain bandwidth product or slew rate, which 33078 does have. RC4560 (TI) only has typical numbers for those. NJM4562 has good noise numbers, plus a lot of typical performance charts.
Datasheetcatalog has no listing for a datasheet on 4562 from national semiconductor, only NJM, so if they want to sell any they need to communicate better. Of course, who cares about diy'ers.
__________________
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

Last edited by indianajo; 20th February 2011 at 06:06 PM.
  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
IVIE 784 - 8x4 PROGRAMMABLE MATRIX MIXER dudaindc Swap Meet 6 2nd October 2012 05:15 PM
Burr Brown op amps,in amps,power op amps for sale magneticnorth Vendor's Bazaar 1 23rd September 2010 10:50 PM
Need help with my first project; 7x6 headphone/monitor/matrix mixer jumpfroggy Headphone Systems 5 10th January 2008 07:36 AM
tda2005 Spice Model or other 12v op matrix99 Chip Amps 1 20th March 2007 05:24 PM
replacing op-amps in mixer DoomPixie Parts 8 20th October 2005 04:43 PM


New To Site? Need Help?

All times are GMT. The time now is 08:42 AM.


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