Capacitors Seem Too Large

[strat56]

Hi All,

First time effects builder here.  I just started on this Direct Drive clone and the capacitors seem to be much too big for the small board.  The electrolytics and box caps came from Mouser and the others from various places.  Is there some specification I can use to get smaller sized caps?  


 

[Beaker]

Congratulations! If that is your first build, it looks very neat. Everything looks fine to me, so don't worry.

Greenies can be a bit of a pain to fit - hence I rarely use them. Instead I (and many of the guys on here) prefer to use MMC (monolithic multilayer ceramic caps) like these:

http://www.ebay.co.uk/itm/10pf-10uf-600pcs-30value-Multilayer-Monolithic-Ceramic-Capacitor-Assorted-Set-/121075015531?pt=LH_DefaultDomain_0&hash=item1c30a21f6b

It's worth getting some axial versions as well for the longer spans.

Someone put up a link for small electrolytics recently - can't remember where I saw it.

Take look through the sticky "bargains" post at the top of the page - It will help you find the good stuff for cheap!

[rocket88]

Mark posted the link under the deals section. The problem is that they are SMD's which will only span 2 rows, unless you add legs to them to get a longer span. Nothing wrong with that, just can be a pain. I bought a bunch of them, actually and use them on compact 1590a builds.

[AC_FX]

Lower voltage rating usually means smaller size, for a given capacitance value and type.  For effects jobs that won't see much more than 9 volts, you can use 16V electrolytics with no problem and you'll save room, say on that 100uf next to the IC which looks like a 50V maybe?  

For nonpolarized caps, Topmay TMC07s (63V boxes) or TMC05 (50V poly film) will be a consistently small size with adequate voltage ratings.

Having said all that. . . . your board looks great, those few bigger-than-necessary caps wouldn't bother me at all!  For builds using 1uf nonpolarized caps, I often have a few lumpier-looking ones than that on the board.  By all means, source smaller caps and you'll make stuffing boards or creating layouts a little easier.  But there's no harm in using up what you've got, it's not out of line.

[rocket88]

Agreed. It looks great and much better then my first few builds. Also, take a look at the link mark posted about the panasonic caps, or panasonic work a likes. They are down right tiny compared to the greenies. I have a few hundred of them, and love them. They guy on eBay that sells them has a sets of them for like $17, which is great.

[Frank_NH]

Ahhh - one of my favorite topics!

Yes, small is good when it comes to capacitors.  A quick story - I recently purchased some 50V ceramic disk capacitors from a vendor on eBay and ordered a wide range of values from 47 pF - 820 pF.  When they arrived they were quite small - definitely smaller than usual (diameter of the cap body about 3 mm).  I was disappointed and thought I'd never use them - they're too small!  But soon after I discovered that they are PERFECT for common layout configurations where you need a small cap with two hole (0.1") spacing, such as the treble roll off cap in the feedback loop of an op amp overdrive.  Plus, because they're small, they never interfere with other nearby components.  I measured them and they are very close to the specified values versus other small caps (which can sometimes be well over 10% off).

For most layouts I use ceramic disks for < 1 nF, box caps for 1 nF - 1 uF, and small electros (16v - 63V) for 1 uF and above.  Be aware that electros can often come in fat diameters even though they're only, say, 25V.  The box caps in particular are great for keeping a layout nice and tidy.  I have noticed that for values of 200 nF - 1 uF, box caps can get big, but Smallbear sells Topmay box caps in this value range which are smaller and hence easier to use.

Finally, I try to be creative in bending the leads if I want to move the body of a cap to one side or the other of the two connection points.  Also you can connect often components diagonally rather than up/down if there are adjacent holes on the same row to connect to.  If those don't work, you may have to live with a crowded board.  

[Travis]

Our Bulgarian pal hooked me up with a bunch of those tiny panasonics in my last order

Love those things!

[bart]

I do agree. The smaller the better. What I often have a problem with is the height of electrolytics. The usual 11mm ones are a bit too tall for 1590b. Once you put the pots in an enclosure, add a layer of insulation tape/foam, or whathever folks use, then some wire that goes underneath the board, the board itself and then I usually end up having trouble closing the lid.

So I decided to invest in 6mm, 7mm, and 8mm mini electrolytics. These things are real helpful nd cute too :) Like these: http://www.ebay.com/itm/500pcs-Nichicon-25V-22UF-Electrolytic-capacitor-6-x-6mm-105-/400752213219?pt=LH_DefaultDomain_0&hash=item5d4eb17ce3

[Frank_NH]

Those mini electros are cute!



I've found that for a standard 1590B, the inside vertical space is about 1.06".  The 16 mm pots take about 3/8", foam barrier layer maybe 1/16".  So that leaves you ~9/16" for the height of your entire board if you allow for a small gap at the top - not much space for tall electros!   The solution?  Use a 125B.  They offer 1.5" height inside, yet the planform is nearly the same as a 1590B.  The 125B is about the same size as a standard BOSS pedal, so they really don't take up that much space on your pedal board.

[GuitarGas]

These were the caps on my first build....

[strat56]

Thanks everyone for the helpful and informative replies, they are much appreciated.  I'd read somewhere that Ceramic caps had a tendency to be noisy sso I stayed away from using them except for one, in this build.  I get the impression from the responses here that many of you use them and those MLCC caps look like the ticket for the size problem.

This is my first effects pedal build (I hope it works when I can finally get it all put together ).  It is not my first electronics project build, I built a couple amp kits, one from Mojotone and one from Allen Amplification before this.  I've always been a little nervous about building effects because of the size of the board and the very small spaces to work in.  The amps were big and I had plenty of room for components and lead dressing.  This is way different.  Everything is so compact, but I'm enjoying it so far.

Thanks,
Jack

[rocket88]

Yea buddy, the multilateral ceramics are similar to the poly caps, like the greenies. They make no noise, or at least very little to the point where you don't hear it. The regular ceramics are still useful, and dirt cheap, just avoid using them for high values, as that's when you'll start to hear noise from them. I actually still use them with certain mojo builds , and when it's a very low value and it won't matter so why waste a multilayer ceramic.

Glad to hear you enjoying building effects. While they may be small to work with, you don't have to worry about being killed by the amprage, like a tube amp. While I haven't built an amp yet, I've been planning s super secret build, that every one here knows about, as I have to start buying the pieces, but the chassis is the hardest part for me to get, as no one makes an orange style chassis.

[Frank_NH]

"While they may be small to work with, you don't have to worry about being killed by the amprage..."

I think Zach meant "amperage"  ...  or maybe it **is** AMP-RAGE!  

In any case, I like the fact that I can stick my fingers into an effects circuit and not have to worry about getting zapped with 300V!  I did briefly get zapped by my solid state acoustic amp - I was repairing the input jack and had the chassis out of the cab.  I was testing out like that and very briefly touched some 120V power connection.  Won't be doing that again!  

Re: amps ... I have built (well helped to build) one tube amp - an 18W twin EL84 push-pull design that used to be on AX84.com called the "Voxy Lady".  It is roughly equivalent to a Vox AC-15 and sounds very sweet.  I can post some pictures of it at some point.  It would have been nice to have incorporated a reverb and tremolo into the design, but that would have complicated things too much and I like it as it is.

[rocket88]

Lol, stupid iPad autocorrect.  I did mean amperage, buts guess there is amp-rage we may need to worry about too.

Shit, when I put in the subpannel in my basement, it's on a 60amp breaker from the main box, I kept accidentally touching the power side when I was wiring the grounds. My dad looked at me and told me or stop touching it, and from one zap I couldn't respond. I literaelly couldn't talk.

People don't understand the voltage isn't your biggest worry, that it's the amperage that'll kill you. This make me uber nervous when I build my amp, which will be 120 tube watts.