[sdiy] [OT] Mixer upgrades

[harry]

Hi Terry:

Don't know if those are carbon or metal film.

I would change to metal film for sure. I've found metal film to
be a lot quieter.  Metal films in large values can have some
inductance greater than a carbon comp. resistor... but probably equal to a
metal film anyway

H^) harry

Terry Michaels wrote:

> Hi All:
>
> I recently picked up an '80s vintage Soundcraft model 200 SR mixer which I
> intend to use for recording purposes.  A look inside shows film type 2%
> resistors with either a blue or violet body color used throughout the unit.
>  Does anyone know if these are carbon film or metal film?  It's generally
> known that metal film resistors generate lower internal noise than carbon
> resistors, if these are indeed carbon resistors, is it worth the trouble of
> changing them out with metal film resistors at least in the front end (mic
> preamp) section?
>
> The front end uses a 2SA1316GR differential pair feeding a TL072, any need
> to upgrade this area?
>
> Electrolytics are known for being less than perfectly linear, so is there
> any benefit in adding disc or film caps across the numerous electrolytics
> in the audio chain?
>
> Schematics for this mixer are available at the Soundcraft web site, in case
> anyone wants to have a look at the circuitry.
>
> Terry Michaels