Where in the UK can I get 10uF mylar or metalized polypropylene capacitors?

[finkfloyd]

Hi

I didnt know where to post this, may be better in the offtopic section..

I came across this interesting simple DIY Pro Microphone project as originally documented here: http://prosoundweb.com/recording/tapeop/buildmic/buildmic_16_1.shtml as I wanted to build 2 mics, one for my speaker cab and one for room ambience when im playing along to backing tracks.

Soundclip of it compared against a Shure SM58 mic and another schematic here: http://www.christianmusicweb.com/microphones/mic_project.html
Direct soundlip link : http://www.christianmusicweb.com/microphones/mic_test.mp3

But I cannot find a 10uf mylar or metalized polypropylene capacitor anywhere round here, and the notes state not to substitute a electrolytic...

Any Help at all appreciated!

Thanks

[JimRayden]

I bought a few mic elements for this project too, haven't gotten to building it yet. Let us know how yours turn out.

----------
Jimbo

[slacker]

Here you go http://www.maplin.co.uk/module.aspx?TabID=1&criteria=AUDIO%20CAPACITOR&ModuleNo=393&doy=13m12
very expensive though.
If they need to be non polar then I'd be tempted to use a couple of 10uF electros to make a non polarised electro.

[Mark Hammer]

Those sorts of values in nonpolarized caps are often found at places that specialize in automobile sound installations, since those are the sorts of caps to be found in crossovers.

[JonFrum]

wherever you find them, they are going to be big and expensive. Which is why electrolytics are used  in +1uF values in the first place.

[Dai H.]

places that sell speaker parts, (woofers, crossovers, coils, etc.) seem to typically have large value film caps also. Some of them are, but not all look particularly expensive.

[Ge_Whiz]

10 x 1uF?

[finkfloyd]

hi thanks for the replys but ...

Audio grade caps are too expensive(I'd love to know why!), the guy on the christian site, has one big mylar cap...


Heres a quote from the component list , electrolytic's are out of bound, now I do not know whether this means non-polar electrolytic caps too as I may try the method slacker mentioned.

Circuit components:

(1) Panasonic WM-66AY Omnidirectional Microphone Cartridge (available from Digi-Key at 800-344-4539, part # P9959-ND). This capsule is a high-quality back electret type with a frequency response that is ruler flat from 20Hz to 20kHz. It contains an internal FET impedance converter making an external FET unnecessary.
(1) 1000 pF ceramic disc capacitor
(1) 10uF mylar or metalized polypropylene capacitor (DO NOT substitute an electrolytic!)
(1) 2.2Kohm 1% metal-film resistor
(1) 9-volt battery terminal w/leads
(1) 9-volt alkaline battery
Insulated copper wire

why is this?

[hank reynolds 3rd]

Can you email the guy the mic schem is on about the non polarised option
I'm not really sure why a non polar would be out of bounds though.........


Sam

[Dai H.]

I think he means don't use an alu electrolytic period (incl. non-polarized). He wants you to use a film, basically. Can't you find a cheaper film cap? At one place here, I saw two 250V 10uF metal. poly films(shizuki and Nissei brands IIRC)--about 6 to 7 bucks (USD)--seems pretty reasonable (bit under 4 pounds). The ones referenced above are about USD$16, much more. They don't have to be "audio grade" or whatever, do they?

[JimRayden]

I don't know about you guys but we here in europe have these 

Wanna go crazy?

These are non-polar, right? riight?

----------
Jimbo

[Mark Hammer]

Some time back, I purchased a handful of metallized film 2u2 caps, rated at a couple hundred volts.  They weren't nearly as huge as you might think, although decidedly bigger than their electrolytic equivalent.

[slacker]

Here's some more, only a quid each

http://www.bardwells.co.uk/detail.asp?stockid=PB008&ref=subcats%2Easp%3Ft%3D%26qfcode%3D%26catid%3DPOLBL001%26manuid%3D%26keywords%3D%26minprice%3D%26maxprice%3D

[finkfloyd]

hi,

Nice find! thank you! Ive ordered a couple amonst some other things, they are very reasonable on prices there.

Thanks much appreciated!

[slacker]

yeah they're a good supplier.
Might still be worth experimenting with electros though, just for the fun of it.
As far as I know there's only 2 reasons not to use electros in a circuit like that. One is because you need a non polarised cap which you can make by putting 2 electros back to back with the positive terminals connected.
The other is because electros allegedly don't sound as good as other types. This might be true in this case but often it's at best subjective and at worst an unfounded statement based on mojo and heresay.
Given the cost of electros and ease of availability compared to other types I'd give them a try and let my ears decide.

[MetalGod]

I've got some 16uF/630v polypropylene caps that I got for £1 each.  I figured I'd use them eventually - had them for 3 years now 

[finkfloyd]

Well I got bored whilst still waiting for the 10uF cap's to arrive, impatience got the better of me, so I tried slackers idea of 2 electro's back to back to make a nonpolar cap, and it works fine!



But..

I only could test through the line-in input with my soundblaster audigy 2 external box, so this is not a dedicated mic-in input as my proper mic-input is broken (opamp blown!)
So obviously without the preamp function, the mic was pretty quiet unless right near the mouth, its good though. cant wait to test with this running through a proper input.

Now if only i had a 1/4inch jack to 3.1mm adapter...

Oh I used a broken soldering iron handle for the casing, and then semi filled with glue, I have a proper mic enclosure for my second attempt.

[finkfloyd]

Hi, well in the end I got hold of a mixer to use as a preamp, to test the Mic then recorded with the pc, and I must say it sounds fantastic.
The sound images it captures are really good, seems to grasp all the low and high frequencies really well.

Im new to using mics for this purpose but understand on/off axis and edge micc'ing.

I had the mic off axis at about 1 and a half foot from the mic.
The amp was at bedroom playing levels.


Pedals used and order:

DIY Tubedriver >Big Muff > Ibanez DE-7 Delay> Amp clean> 2x12 Cab

Some early soundclips.

Example 1
http://www.rogepost.com/n/8623159736

Example 2

http://www.rogepost.com/n/9788663572

I'd also like to note the Mic is also picking up the backing track too!

For the cost of making these things, it seriously cost me about £1.50 to make one, they are great!, even though they look rough!

[Ronsonic]

That sort of capacitor value is common as dirt in speaker crossovers.  It's like standard issue on the tweeter. Any shop that repairs speakers and crossovers is going to have them.

Ron

[finkfloyd]

Thanks,
I did hold of some in the end from bardwells, they are massive, but the above mic, is just using just 2 electro's back to back to make a non polar cap. (which is a lot cheaper)