[sdiy] Using both OTAs in 13700 as one OTA

[Ian Fritz]

The reference to the original Jung article is JAES, 23, 1975. This 
method was widely used in EN projects. I looked at using this method 
with the LM13700 to aid people who want to build off of these projects, 
but who can't obtain the CA3080. It's also an easy way to improve S/N by 
3dB, as pointed out by Serge T. in his EN article from when the chip was 
new.

I couldn't wade through Aaron's article either.  It sounded like 
negating then subtracting?  Isn't that the same as adding?

Ian


On 2/8/2016 2:41 AM, Mattias Rickardsson wrote:
> On 4 February 2016 at 05:52,  <ijfritz at comcast.net> wrote:
>> Good grief!  Just connect them directly in parallel.  An example, complete
>> with the W. Jung trick:
>>
>> http://electro-music.com/forum/viewtopic.php?highlight=jung+ota&t=50884
>
> What does it do? What is the "trick"?
> I feel like one of the answers in that thread:
> "I hadn't heard of this trick before, is there an article somewhere
> that explains the benefit of drawing bias current from V-? I feel like
> there's something obvious that I'm missing."
>
> I spontaneously found Aaron's idea potentially better than nothing,
> but I haven't plunged into it.
>
> /mr
>