Quality capacitors without breaking the bank

[philb]

I am building Rod Elliot's constant Q expandable graphic equaliser. http://www.sound.westhost.com/project75.htm .

I have been reading and re-reading his article for a few weeks putting together everything i can find. I have come to choosing components, and have run into a snag. I would like to use foil polyprop caps, but since the circuit requires so many caps i will be broke. Also 1% metal film capacitors are not cheap.

I was looking at digikey BC components metalized POLYESTER film caps, and yageo 1% metal film resistors.

Are these good choices, or are is there a better bang for my buck? Thanks guys.

 

[sagarverma]

both r good.
i made his 12db xover with philips m/f caps.its working great.

 

[head_spaz]

digikey BC components metalized POLYESTER film caps

Can you give me a page number in their online catalog for these?
I did a search and see only polypropylene listed for BC components. Even so... I couldn't find any metalized versions.

I used Polypropylene Film from EPCOS @ 5% tolerance in my last EQ project. They work good.

 

[jpl]

Try E-bay very cheap .

 

[philb]

head_spaz

the BC components caps were metalized POLYESTER film caps, not polyprops. Thanks for the heads up on epcos polyprop caps, but i think for a few bucks extra i will go with the tighter toleracne of the BC componenets metallized POLYPROP filter caps, unless there is a reason i should not.

I will aslo check e-bay but i don't think i will find all the value.

Thanks fot the help, i'll post pics when i start building.

 

[SyncTronX]

Hi PhilB,

Thinking that a graphic equilizer might be similar to a speaker crossover
you might want to use film and foils rather than metalized film.

RNMarsh discussed this around here in a few of his posts. I think it
has to do with resonances, distortion because the metal particles
are applied to the film in metal films while in film foil they are
separate layers and produce less distortion.

More expensive and larger, but probably worth it.

 

[DF96]

Graphic equalisers typically handle smaller signals than speaker passive crossover networks, so distortion is less of an issue. Dielectric linearity is the thing to look at, which may suggest polyester is not the first choice.

 

[AndrewT]

1% metal film resistors are standard stock for most retailers.
I buy mine from Rapid online @ ~ £1.60+vat per 100.
That's less the 2p each.