[sdiy] DIP LM13700 discontinuation

[Steve Lenham]

On 20/05/2021 12:15, mark verbos via Synth-diy wrote:

> I saw the announcement of this chip on the Alfa site, but I couldn’t think of a use for it. What would one do with that? I guess replace the whole expo section (summing opamp, matched pair, temperature compensation, servo) of an existing VCO?

My reading of it is that you could use the AS3341 anywhere you used to 
use the long-lamented uA726. It is effectively a temperature-compensated 
matched pair of transistors, but whereas the 726 burns power to keep the 
pair at a constant temperature, the 3341 uses circuitry to modify the CV 
to track whatever temperature the pair happens to be at.

There are lots of classic synth circuits using the uA726: Elektor 
Formant, Roland JP-4, Teisco S110F/SX400 and so on. It gives you more 
freedom to do something a bit different, which is useful now every man 
and his dog can build a CEM3340-based poly.

>> On May 19, 2021, at 11:06 PM, Ben Bradley via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> I'll happily take DIP going away if it would help availability of more of these new/newly remanufactured chips. I looked on the Alfa Rpar site and saw the AS3341, essentially the exponential converter section of the AS/CEM3340 oscillator with the expo current brought out to a pin. I've got some good ideas for this, but I'd have to be able to buy it. There are boutique distributors that have some of these new and newly remade parts, but none that I've seen carrying a manufacturer's whole line. I'd email the manufacturer but I doubt I could afford the MOQ, and I'd rather not become a boutique reseller myself. I see ebay has sellers of the AS3340 and such, but not the AS3341.

The AS3341 datasheet is marked "Preliminary", so perhaps it has not been 
released to the market yet. One would hope that the small distributors 
that carry Alfa parts will list them when they are or, at the very 
least, be able to source them to order.

Cheers,

Steve L.
Benden Sound Technology