Transistor arrays and strange opamps

Chris Crosskey chrisc at
Sun Mar 9 14:49:48 CET 1997's OK guy's I'll get it.......

>	I am currently looking into building a small portable synth
>	based on the venerable tb303, probably with an extra oscillator
>	and a few modulatin options.
>	The oscillator uses a dual npn ( 2sc1583 ). I am considering using
>	a quad npn chip (en2016cn) the devices are similar to 2n3904
>	transistors. Anybody used the en2016cn? Any info on the 2sc1583 ?
The 2SC1583 is a Mitsubishi part, you can probably get them from Mitsu 
themselves, if you must, it isn't special, the EN2016 is an Elantec 
part and is basically four fairly well matched (though not laser 
trimmed) 2N3904's, you'll probably get away with it....

>	OK next. The filter is a transistor ladder design based on 10 devices
>	all npn. THere are two dual npn's one is a 2sc1583, the other is 
>	2sc2291, which I guess is a 2sc1583 except the emitters aren't
>	tied together. Again I'm looking at the en2016cn. Also is there
>	anything to be gained in having matched transistors throughout the
>	filter ladder ?

2sc2291 is a Sanyo part try them doesn't look special in the 
datasheets, matched trannies? shouldn't have thought so......
>	There are a couple of opamps I have been unable to find out anything
>	about,  an6562  and ba6562a, anybody any ideas ? Of course all these
>	devices could well be Roland specific.

The BA662 I think you mean, it's a ROland special dual OTA

>	Just found another transistor array, the ca3046. This is a lot
>	cheaper but there is the additional problem of having to connect
>	the substrate to the most -ve voltage ( doesn't apply to en2016cn ).

The 3046 is five crap trannies in a coffin, it's a good idea to 
substrate the 2016 BTW, but at least it has it's own pin....
>	The RS catalogue lists a few 2sc devices all made by Toshiba if that's
>	any help.
>	A lot of questions I know, but hopefully someone has the knowledge,
>	Thanks in advance,

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