[sdiy] Blast from the past EFM VCO4d

[crystal]

furthur digging thru the treasure pile has revealed some MAT04s! but 
really they seem too good for the job, like i should save them for 
something better?

is there a chart comparing:

LM3046   (OK?)
THAT300  (GOOD)
MAT04  (VERY GOOD)
SSM2220  (GREAT)

do i have this correct? where are looking at matched leakage current and 
temp tracking, correct?






On 10/17/2014 10:55 AM, crystal wrote:
> hi DIYers,
>
> i recently discovered a pile of old EFM pcbs in my "well organized" 
> room full of electronics junk. amongst them were some VCO4d (and 4e) 
> boards. i'm thinking they would at very least make decent VCLFOs but 
> perhaps with some work i could get serviceable VCOs with them. i'd 
> like to get 8 octaves of 1V/oct.
>
> as per a harry bissell suggestion i am going to use a zener or 
> precision reference zener in place of R32. i could swap out the LM3046 
> for a better matched pair (but i do have a bunch of them). is the LS312
>
> http://www.linearsystems.com/assets/media/file/datasheets/LS310-3.pdf
>
> a good choice? if not what is these days?
> i recently purchased some of these smt matched pairs:
>
> http://www.nxp.com/products/bipolar_transistors/general_purpose_bipolar_transistors/matched_pair_transistors/BCM847BS.html 
>
>
> but they are so small that even with a magnifier i doubt i can work 
> with them.
>
> does the FET  (J112) make any difference?
>
> i know this has been hashed, rehashed, double extra super duper 
> rehashed in years past. my ability to search the archives seems 
> somewhat limited perhaps i am doing it wrong. any tips or pointer 
> appreciated.
>
> (a guy named) crystal
>


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