Discussion about the Korg PolySix synthesizer

Hello Andrew,

Cool, thank you for elaborating on the matching procedure, this will 
come in handy for fabricating the PNP/NPN replacements of this type, 
probably also for other obsolete parts and where a compareable circuit 
is used :)

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Greetings,

Simon

(9-0-9)

On 2018-03-02 17:16, axmonti@yahoo.ca [PolySix] wrote:

> Hi 9-0-9,
> 
> I've made plenty of replacements for the 2SA798 - just use two matched 
> PNP transistors and place them back-to-back with their emitter tied 
> together.
> 
> Here are the transistors I use (I order at least 10 to end up with a 
> matching pair).
> 
> Here's the circuit you need to build (the PNP one) to match 
> transistors. I recommend ordering two 0.1% resistors for your tester to 
> avoid having to add a pot to make up the slight difference in 
> resistance between the pair. You also have to have a +/- power supply 
> (12-18V is fine) setup.
> 
> The 2SA798 pinout is BCECB, so it's easy to tie the emitters together. 
> Some people epoxy or zip-tie the transistors together, but they are 
> pretty much exposed to the same temperature within an enclosed case, so 
> I haven't found a need to perform that extra step.
> 
> You can also use the same procedure to build 2SC1583 replacements; just 
> use an NPN transistor such as this one (and flip the diode and power 
> supply in the transistor matching circuit).
> 
> Hope this helps!
> - Andrew
> 
> 
> 
> -------------------------
> Posted by: axmonti@yahoo.ca
> -------------------------