http://www.precisionresistor.com/pt146-25w-custom-tcr-temperature-sensitive-wire-wound-axial-pr-34.html
I have purchased from them in the past but that was a number of years ago. Their product was an excellent performer for VCOs. I suggest the PT-146 and you can buy direct for $4.50 each (quantity 1). The PT-146 is always a stock item so no long wait to get your parts.
No, I have no connection with this company. I don't know of a European vendor ... sorry.
I think Synthtech uses KRL Bantry tempcos but I do not have a part number for them.
Tom Farrand
I found a datasheet on the Tyco website which refers to two types with a temp coeff. of 3000 and 3300 ppm.
André, en tout cas merci pour l' info ...
--- In motm@yahoogroups.com, Andre Majorel wrote:
>
> On 2010-05-03 12:12 -0000, peter_ivens wrote:
>
> > A tempco with a temp. coeff. of 3500 , 1K 1%, is not so
> > difficult to find. Most moduls of MOTM use a tempco of 3500 ppm
> > (like the MOTM-300) but in the BOM for the 440 & 485 there is
> > specified 1K 1% 3300 ppm.
>
> I don't think it matters much. The tempco of the circuit is
> an approximation anyway, because there are other sources of error
> than the transistor pair. And so is the tempco of the actual
> resistor because it varies with temperature (and possibly from
> device to device).
>
> If anything, it's preferable to have a resistor with too high a
> tempco because you can always reduce it by wiring an ordinary
> metal film resistor in parallel (metal film resistors have tempcos
> like 50 or 100 PPM/K).
>
> Check Ian Fritz's "dial-a-tempco" page for a really refined
> treatment.
>
>; > Elby design delivers a second resitor to lower the temp. coeff.
> > but then you can take also a tempco with a tolerance of 5% from
> > Tyco.
>
> Tycos are cheap but aren't they 3000 PPM/K ? The Akaneohm sound
> like a much better deal. Or the Panasonic SMT if you're prepared
> to some kludgery.
>
> --
> André Majorel http://www.teaser.fr/~amajorel/
>