Tempco Resistors (ONE MORE TIME!) was: thermal tips re expo conve rters

[List, Christopher]

I believe Paul Schreibler still has 1K temcos for sale - they're just as
good as the 2K if you adjust some other resistor values. I have a few
tempcos, but they're all reserved for personal use.

As I've mentioned before,
3500ppm, 1%, 2K tempcos (actually any kind of tempco) can be purchased from;
KRL/Banty Components
Manchester, NH
USA

- you can get their number from directory.

You want part #C-2AQ. Some of their models have a high inductance and won't
work as the feedback resistor in a summing op-amp, but the C-2AQ works llike
a charm (you can read my whole saga of triumph, defeat and triumph again
with the high-inductance models in the 1996 archives :). They have a minimum
order of $100, and the resistors are about $3 a piece. I ordered a batch
about 2 or 3 years ago and sold extras to the list.

Trust me, getting tempco resistors is no big deal if a few people chip in
and someone's willing to organize it and mail them out. They're a simple
solution and not all that expensive (what's an extra $2 or $3 per VCO? how
much will you spend on trim pots and chips for a heater solution?) - All
this heater stuff seems like way too much extra work and circuitry to me.

- CList


> -----Original Message-----
> From:	Steve Varner [SMTP:varner at k-online.com]
> Sent:	Monday, February 15, 1999 12:43 PM
> To:	synth-diy
> Subject:	Re: AW: AW: [Re: thermal tips re expo converters:]
> 
> OK folks...my brain hurts now, thank you very much...
> So, if I'm using a ribbon controller or a theramin controller or
> something, I
> shouldn't worry about any of this. Right? It seems some of you are saying
> that
> isolation has cons as well as pros. My plan was to try to avoid
> temperature
> compensation because of the tempco resistor's cost and hard-to-find
> nature. If
> I'm not getting much benefit from isolation because of cooling and/or loop
> problems, I'll just leave it off and heat the chip sans styrofoam. Again,
> any
> 2K tempcos for sale?  :-0
> 
> SV
>