[sdiy] advice on mixer/summer circuits

[Dave Magnuson]

You're right, mixers are usually inverting.    I'll leave the explaination 
to some of the more theory-minded listmembers...

That being said, when I build a mixer, I usually use a dual opamp like the 
TL072/TL082.   One op-amp is the summer, the other is a unity gain inverting 
buffer.

Use an opamp instead of the 40106.... unless you want some serious clipping! 
40106 is for logic signals.

The CV summer will be the same circuit as an audio mixer, except you'd omit 
any series capacitors at input / output

Dave Magnuson


----- Original Message ----- 
From: "Dan Snazelle" <subjectivity at hotmail.com>
To: "Mark Smart" <marksmartus at gmail.com>; <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, July 27, 2008 2:25 PM
Subject: [sdiy] advice on mixer/summer circuits


>
> i am building a very large custom fx/synth/noisemaker thing for a friend. 
> i am going to be mixing a vco, a ring mod, an audio input, and a few other 
> things...this is all going into the audio input of an ssm2044.
>
> (all mixing will be done pre-filter)
>
> I will also be using a CV summer for all the cv signals that will be going 
> into the A/R, VCO, LFO, VCA, AND FILTER.
>
>
> SO...first question-why are all the good mixers Inverting? doesnt that 
> mean i would need to put inverted audio into the mixer? is there an easy 
> way around this other than sticking an inverter after the mixer? (which is 
> what i will most likely do...is a 40106 ok for this?
>
>
> thanks all
>
>
>
>
>
>
> --------------------------------------------
> check out various dan music at:
>
> http://www.myspace.com/lossnyc
>
>
> http://www.soundclick.com/lossnyc.htm
>
>
> http://www.indie911.com/dan-snazelle
> (or for techno) http://www.myspace.com/snazelle
>
>
>> Date: Sun, 27 Jul 2008 09:46:18 -0500
>> From: marksmartus at gmail.com
>> To: Synth-diy at dropmix.xs4all.nl
>> Subject: Re: [sdiy] WTB:SAD512 chips
>> CC:
>>
>> I believe I read that SAD1024 chips can be used in an ARP Omni 2
>> chorus board. The particular type of SAD512s used in the Omni 2 have
>> the same pinout as an SAD1024 with only one of the halves wired up.
>> Apparently, there were some SAD1024s that were manufactured with flaws
>> that disabled one of the delay lines. So they wired whichever delay
>> line was working to one set of pins and called it an SAD512! There are
>> also different SAD512s that have fewer pins.
>>
>> Someone correct me if I'm wrong. I remember reading this somewhere,
>> maybe on this list.
>>
>> So if you are building an Omni 2 chorus board from scratch, then you
>> can probably use small-package SAD512s or SAD1024s in place of the
>> large-package SAD512s and it will still work.
>>
>> If you are building one from scratch, but are using exactly the same
>> layout as the original Omni board, then you can use either
>> large-package SAD512s or SAD1024s.
>>
>> --
>> Mark Smart
>> http://cdbaby.com/cd/marksmart
>> http://www.marksmart.net
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
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