[sdiy] THAT2162 vs SSM2164 (was Re: (re-)introduction)

David G Dixon dixon at mail.ubc.ca
Wed Nov 27 19:13:46 CET 2013

> 2) THAT2162 is non-inverting. There are a number of occasions 
> where the inverting nature of the 2164 is very helpful. 
> Olivier Gillet's "Four Pole Mission" Xpander-style filter is 
> a good example:
> http://mutable-instruments.net/shruthi1/build/4pm
> This design wouldn't be half so neat without the inverting 
> SSM2164 stages. In fact, it'd be nearly as messy as the 
> original Xpander filter, which was covered in inverters for 
> exactly this reason.

The 2164 is a current amplifier.  It does not invert the current.  Positive
current in gives positive current out, and negative current in gives
negative current out.  However, the 2164 must terminate at virtual ground,
so the following I-V converter is always necessarily going to be an
inverter.  In that sense the 2164 inverts.

> The rest of the differences are mostly fairly minor in my 
> view - variations in spec (as you say, THAT is more hifi) and 
> value tweaks. If I ever actually make the jump to SMD, I can 
> see this THAT chip going right up my list.

2164 is also available in SMD, from Coolaudio.

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