[sdiy] Mixer module (was: Changing an LM13x00 with a LM13x00)

[Tom Adam]

Thanks Guys

I'm thinking about making a mixer module with CV-pan possibilities with 
regular line outputs and 10Vp-p inputs.
Since I got like 10 LM13x00 around I was thinking about using these. 
I've also got a bunch CA3280 around.
Which one would you use for this kind of operation?
What's the best way: attenuate to line levels and do the CV-pan option 
than or the other way around? (I guess the other way around would be 
better.)
I also would like to include a way to inverse the CV (So one signal goes 
right while the other signal goes left) Do I need an inverse op-amp 
circuit or could I do this just using caps? (If I recall correctly a cap 
gives a 90° phase shift??? It's been a while...and I'm more or less a 
newbie;-)
I'll post my final circuit for your comments ;-)
Cheers,
Tom




harrybissell wrote:

>uhhh no... Three...
>
>Three answers...
>
>OTA, Buffer, and 'who cares'
>
>Among the many answers...
>
>1) What Jim said
>
>2) The 13600 has a connection between the Gm bias input and the buffer...
>so it is variable bias.  Better for full range, but a fast moving control signal
>
>might couple in through the buffer
>
>3) The 13700  has a fixed bias... you cannot change it. Its good for most apps.
>
>4)  TRY it.  In most cases they can be swapped with no noticible effect on
>performance.
>
>H^) harry    (among our many weapons are fear, surprise, torture, and an almost
>fanatical devotion... :^)
>
>James Patchell wrote:
>
>  
>
>>There are two answers....
>>
>>         Using only the OTA section....interchange to your hearts content...
>>
>>         Also using the BUFFER section....No, they are not 100%
>>compatible.  The buffer sections are biased differently in the two chips,
>>and some applications, this makes a big difference.
>>
>>At 02:53 PM 12/16/2005 +0000, tom.adam at telenet.be wrote:
>>    
>>
>>>Guys,
>>>
>>>I was wondering if it's possible to interchange a LM13700 & LM13600
>>>without  other changes?
>>>I noticed on the datasheet that the buffer input current is entirely
>>>different so I guess I need to change some resistor values?
>>>
>>>Cheers,
>>>Tom
>>>      
>>>
>>         -Jim
>>***************************************************************
>>http://www.oldcrows.net/~patchell
>>
>>***************************************************************
>>    
>>
>
>
>
>
>  
>

-- 
Tom Adam
The Big Ear
http://users.pandora.be/the-big-ear/
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