Can I replace BSIAB;s 1uf electrolythic cap with 1uf film cap?

Started by jpm83, January 26, 2007, 10:52:05 AM

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jpm83

So there is the question. Thanks in advance for anyone who answers.

Janne

John Lyons

Yes, please do!
Film caps are "better" and will last forever. The are "faster" in resoponce although 1uf is small as far as electrolytics are concerned, usually it's the larger values that are sluggish.

Now if you can show me a source of small and inexpensive film caps in 1uf....

John
Basic Audio Pedals
www.basicaudio.net/

jpm83

Thanks. I bought the caps from here http://www.spelektroniikka.fi , but they were not cheap 0,50 euros a piece. For those 5mm r. poly caps. On the catlogue-06 film caps are labelled as polko.

Janne

zachomega

Depending on how you define expensive...Futurlec has 1uf film caps for 40 cents each.  I do warn you though, they are quite large physically. 

-Zach Omega

Quote from: Basicaudio on January 26, 2007, 10:58:22 AM
Yes, please do!
Film caps are "better" and will last forever. The are "faster" in resoponce although 1uf is small as far as electrolytics are concerned, usually it's the larger values that are sluggish.

Now if you can show me a source of small and inexpensive film caps in 1uf....

John

R.G.

QuoteNow if you can show me a source of small and inexpensive film caps in 1uf....
Mouser:
75-MKT1822510064
871-B32529C105K189

for just two part numbers.

Digikey and Mouser both carry 1uF 50V/63V boxed polyester caps from at least three manufacturers. They're about $0.50 each.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

zachomega

I just measured the ones from futurlec on my micrometer.  The cap's lead spacing and length are approximately .856"  The width is .3" approximately and the height is .6" approximately.

EDIT I should note I have the 250volt caps which came in the poly assortment rather than the 100 volts ones which might be smaller.

-Zach Omega

John Lyons

Ok, that's what I have been getting RG. Notthing wrong with that... Just dreaming a even cheaper source...

Zach, thanks. For something on perf or a non crowded build that will work, but most layouts need the 50/63volts caps in order to fit best.


John

Basic Audio Pedals
www.basicaudio.net/

mojotron

Quote from: Basicaudio on January 26, 2007, 10:58:22 AM
Yes, please do!
Film caps are "better" and will last forever. The are "faster" in resoponce although 1uf is small as far as electrolytic are concerned, usually it's the larger values that are sluggish.

Now if you can show me a source of small and inexpensive film caps in 1uf....

John
A couple of .47uF in parallel work fine for this too. I've had an a few interesting experiences subbing in film caps for polarized electrolytic in opamp based circuits, but in the BSIABx I have tried this and it works, though I don't really hear a difference in sound between non-polarized electro and film caps.

jpm83

I have one question about resistors. I didn't have a 4,7k resistor so I used two 10k resistors in parallel and they give me 4,9k resistance does this effect to the tone.

Janne

petemoore

  If it's on a source and doing gain setting, very little or can be compensated for w/gain control. 4k7 Vs. 4k9...sure, I parallel resistors and fudge values all the time, no-one'll ever know the difference, depends on 'where in the circuit' of course, which way your going [up or down in value] and whether that takes gain up or down and whether your happening to come out very near an 'edge' say of oscillation. you probbly can't tell. Use 5kLpot>+1k there, set to 4k7, listen, turn up to 4k9, listen.
  5k pots measure to about 4k8 - 4k9 mostly.
  Show me where it is and I'll probably repsond it won't matter much at all.
  Most of these schematics are figureing the use of parts tolerances of resistors being +/-10%, often that can be stretched to 20% tolerance or more N/P, perhaps you like...
  Having fun trying calculator, I came up with .04, when punching in 4.9 divided by 4.7, all I can say with my calc abilities is that whatever it is is close, small difference. Maybe you're better at math and can grade my numbers?
 
 
Convention creates following, following creates convention.

jpm83


MKB

FWIW, I have tried replacing electrolytics with film caps in amps, and actually the electros sounded a lot better in that application (cathode resistor bypass caps in overdrive stage of a Yamaha T100C tube amp).  I've also found that in some amp power supplies electros sound better than large film caps as the film caps smooth the sound of the amp too much.  So YMMV.  Cap dielectrics can make a big difference in the sound of an effect, so it usually works best to use what the designer specifies at least as a starting point.

phil

Quote from: Basicaudio on January 26, 2007, 10:58:22 AM
Now if you can show me a source of small and inexpensive film caps in 1uf....
John

How about this - not exactly small (100v), but inexpensive - 10 for $2.00!

http://www.effectsconnection.com/oscommerce/index.php?cPath=34

John Lyons

I think the conscensus is that electrolytics are slow and can blur/soften the sound a bit at higher ufs which can be a good thing.
Larger electro caps suffer at the high end frequencies... Film caps have more "clarity" which may make the sound too clear.
There may or may not be a difference in the sound but at times and especially where ion the circuit the caps or caps are can make a difference.
Also, replacing one cap may not be that audible but swapping out several will be much easier to tell.
This goes for all caps and components. All very subjective.

Thanks for the link Phil! I'll check that out.

John


Basic Audio Pedals
www.basicaudio.net/

Dai H.

you might have to tweak the value to get things to sound right when going from alu elect. to film also. Some (more in hi-fi it seems) say alu electros are not desirable for a good sound, but IME this isn't quite true (meaning I think you can still get a good sound with them, and if you are *producing* sound in amps, efx. etc. as opposed to trying to reproduce sound accurately, then the alu. electro. might sound better). Also, I think if you consider their low cost and volumetric efficiency, alu electros definitely have their value and place in the scheme of things.