'GLOBAL CAPACITOR SHOOTOUT'

CRBMoA · Post by **CRBMoA** » 28 Feb 2010, 02:31

I am operating on the understanding that we have chosen the Colorsound OD circuit as the platform, I will be getting some MUCH appreciated assitance with the layout from RnFR, and we will be haggling over the number and placement of the capacitor combinations.

Here is what I am envisioning for the next few weeks:

Layout, switch arrangements , etc, get ironed out to the satisfaction of all (Or at least most

). The hand-picked caps will be forwarded to me. I hope someone has a stash of big switches, but that is a relatively small matter.

I will take extensive pics of the build, and log detailed build notes. I will seal the Buzy Box in a manner we agree upon to ensure that the box remains tamper-proof.

We could establish a Paypal account, or use a trusted existing member's account, for any contributed funds. I have no desire to handle the funds, but will do so if asked.

Particpants in the tryout/recording process can help the cause by paying postage from themselves to the next tester.

I am very excited to see this idea unfolding, and I am learning much from the discussions.

KindaFuzzy · Post by **KindaFuzzy** » 28 Feb 2010, 03:09

here's some caps I can donate just let me know which ones.

In the .1 cap picture there's some glass encased ceramics, cool military tants from RnFR, little monolytics and the red ones are wimas.

RnFR · Post by **RnFR** » 28 Feb 2010, 06:04

just to be clear, i said i'd draw up a schematic. haven't given much thought to a layout as of yet. although i know my way around eagle, i'm sure that there are some out there that might have a better understanding of what to do with a project such as this.

regarding those .1 polystyrenes i have- they are 1% tolerance. so, although they are rather large, if we want to use them(which i think would be perfect for this project) it should be easy pickins.

CRBMoA · Post by **CRBMoA** » 28 Feb 2010, 07:15

Schematic, right, that IS what you said.

I am not worried about the layout, as I believe the needs of the switching and the size of some of the caps will force the final layout.

And I did order a Capacitor Tester from somewhere in Asia. I'll build it up for kicks while you Big Dogs are working up the specifics of the test circuit.

MoonWatcher · Post by **MoonWatcher** » 28 Feb 2010, 13:01

RnFR wrote:haven't given much thought to a layout as of yet.

Fuzz Central has a nice, easy, big layout:

http://fuzzcentral.ssguitar.com/pcbs/ov ... layout.gif

and a toner transfer to go with it:

http://fuzzcentral.ssguitar.com/pcbs/overdriverpcb.gif

As long as we're cool with a BB box, it makes the build easy. The only caveat is that this layout assumes that trannies with a standard E/B/C type of pinout will be used. Since many folks like to build these things with certain trannies with different pinouts, it can become a troubleshooting issue.

...And this particular layout is so simple and spread out that it would be easy to adapt to perf/vero as well, if necessary.

MoonWatcher · Post by **MoonWatcher** » 28 Feb 2010, 13:26

umutgokcen wrote:I was trying out some caps in a big muff tone stack today and I could barely tell the difference between 0.01 and 0.012. That's 20%.

That's because it's a low pass filter. Assuming that your resistor with it was 39K, you start chopping off treble at the following frequencies:

with 10nF - 408Hz
with 12nF - 340Hz

Those two numbers may seem vastly difference with a "spread" of almost 70Hz, but when you consider that they are in the midbass range, it is typically perceived as a subtle difference.

The test that you did is sort of similar to the tone cap swap that was done in the parent thread.

Repeat the above with two different caps for the treble cap, and the difference should be more noticeable with a 20% variance:

3.9nF/39K - 1047Hz
3.1nF/39K - 1317Hz
4.7nF/39K - 996Hz

...decrease the R in the HP filter, and it gets even more extreme:

3.9nF/22K - 1856Hz
3.1nF/22K - 2335Hz
4.7nF/22K - 1540Hz

...given the fact that the upper order harmonics are in these ranges and higher, the audible differences can (and should be) very dramatic.

So what is our tolerance, if any? Can we agree on something? The other pieces seem to be falling into place. If someone actually wants to start sorting at 1% (or dead on) with at least electros, that could start right now. When we reach consensus on the other two dialectric types (which we should pin down soon, IMO), sorting for them should start, as well. I think that polyester is a great one. And ceramic s/b the other IMO - I'd really like for it to be "Gus's forbidden ceramic" if possible.

georgeb4 · Post by **georgeb4** » 28 Feb 2010, 15:37

I'd like to volunteer as a tester. Thanks to having the right kind of friends, I can provide high quality recordings with fairly consistent performances from one take to the next. In the coming days / weeks we should discuss the optimal format for recording and posting. Assuming there will be 3 different options (ceramic, PET, electrolytic) I like the idea of an ABCX format. In other words, explicitly state the recording is position 1, 2, 3, then a 4th where you do not say which position it is. I'd also like to hear recordings not only thru an amp and speakers, but also of the pedal directly into the board. Not a realistic scenario, but it might be more telling in terms of what the pedal is doing on its own.

Good times!

umutgokcen · Post by **umutgokcen** » 28 Feb 2010, 18:52

Thanks for the clarification MoonWatcher, that was helpful

Dan N · Post by **Dan N** » 01 Mar 2010, 09:20

I haven't read the other (10 page

) thread so maybe this has been covered...

Why not build a LPB-1? It uses just two 0.1uf caps. It's a very simple circuit and caps have a dramatic effect in there. Pretty much the same circuit can be a treble booster, a power booster, or a bass booster depending on cap values. There's really not much excess stuff to color your signal other than the one transistor and the two caps. Dogs or diamonds will have no place to hide.

CRBMoA · Post by **CRBMoA** » 01 Mar 2010, 16:34

Dan N wrote:I haven't read the other (10 page ) thread so maybe this has been covered...

Why not build a LPB-1? It uses just two 0.1uf caps. It's a very simple circuit and caps have a dramatic effect in there. Pretty much the same circuit can be a treble booster, a power booster, or a bass booster depending on cap values. There's really not much excess stuff to color your signal other than the one transistor and the two caps. Dogs or diamonds will have no place to hide.

Dan,

I am just the solder jockey on this project. It is above my paygrade to make intelligent descisions regarding the platform circuit. I'll leave that to the guys that understand how to draw circuits.

Where abouts in Oregon? The 'Buzy Box' will be assembled in The Dalles when we get all the details worked out.

CRBMoA

Dan N · Post by **Dan N** » 01 Mar 2010, 20:34

Hi man, I'm down in Eugene.

CRBMoA · Post by **CRBMoA** » 04 Mar 2010, 05:23

Dan N wrote:Hi man, I'm down in Eugene.

OK. I am in The Dalles and you are in Berkley North, but where did evryone else go??

Greg · Post by **Greg** » 04 Mar 2010, 05:37

We're all watching with bated breath..

CRBMoA · Post by **CRBMoA** » 04 Mar 2010, 05:48

Greg_G wrote:We're all watching with bated breath..

I thought the 'committee' was going to decide where the switches should go, and what we should load them with.

I'll give it a day or so. Then I'll just put up a proposal and duck!

MoonWatcher · Post by **MoonWatcher** » 04 Mar 2010, 12:30

CRBMoA wrote:I thought the 'committee' was going to decide where the switches should go, and what we should load them with.

I'll give it a day or so. Then I'll just put up a proposal and duck!

It might be necessary! I've made my suggestions and proposals - perhaps too many, so I tried to cool it a bit. Also been tied up.

So what we need are other members to "second the motion" and so on.

Maybe the fire just needs to be re-lit. The "proposal" so far:

- Colorsound Overdriver circuit.
- Four caps switched out to the homogenized value of 100nF.
- Caps must measure to within 1%, preferably dead on.
- Switching will be done with a 4P3T rotary.
- Dielectrics will be polyester, electrolytic, and ceramic.

...I think that we should switch out the input and output caps (stock value 220nF), the 6.4uF coupler at Q2's collector, and the 25uF cap on the output of the tone stack. If anyone thinks that other caps should be added or that a different four caps should be switched, let's make a decision in the next 24 hours and run with it.

Of course proposing switching more than four caps will mean that someone is on the hook for the details on how to do it.

Let's get cracking. At the very least, the pedal build should start. And folks with the parts should start mailing them.

RnFR · Post by **RnFR** » 04 Mar 2010, 15:12

i'd like to add these 1% polystyrenes i've got into the mix as well. if we are trying to get the biggest difference between dialectric efficiency, then i believe this would be the way to go.

switching more caps could be done with 2 rotarys.

CRBMoA · Post by **CRBMoA** » 04 Mar 2010, 16:55

OK - I just typed a page long response (TWICE), but my office computer logged me off again (I have my tech coming this morning, AGAIN!).

So, excuse my brevity;

I have THIS enclosure, which is large, lightweight (for shipping), easy to drill, and I have it in stock. The Hammonds I have are too small, I think.

I have In/Out jacks, 3PDT, battery clip and D/C jack, LED, resistors and caps and perf or vero. I am out of 100K pots at the moment.

If you have pots, caps for the test, SWITCHES, let us know in the thread, and PM me for shipping details.

If you would like to contribute $$ for the postage fund, let us know in the thread and PM me for Paypal details.

Thanks!

Kollaps · Post by **Kollaps** » 05 Mar 2010, 05:22

I'm in Los Angeles, and I'd like to help however I can. Let me know. Money is a bit of an issue right now, but I have a few piles of parts of different values and dialectics that are probably never going to get used, and I might be able to send some of those.

CRBMoA · Post by **CRBMoA** » 09 Mar 2010, 05:42

Sorry I haven't added anything the past few days. I have been weighed down with a group buy I am running on another board.

I would still like this to happen. I can build the circuit, but I am really hoping some of the guys with more credibility and knowledge can throw their weight behind this project. Not even talking about money and or parts. Those would be nice.

Nobody is gonna care if some dweeb with 50 posts builds this box by himself.

And even if I build it, I lack the gear to properly record, and no one wants to listen to what I would record.

Global Capacitor Shootout Signup List

^^^^^ This is a sign up document I created. Who's in?

PayPal address and/or address to ship parts (capacitors and switches) are available on request.

Thanks for looking.

Chris

CRBMoA · Post by **CRBMoA** » 23 Mar 2010, 23:15

I have been sidetracked with a different project.

No one has signed up on my sheet, which is fine. I have the parts I was lacking being shipped to me now. Except the switches, because I don't recall a definitive spec for them.

I will build the circuit on perf with sockets where I think the cap switching should be, take pics and then the project either gets legs or I learn something on my own.

Thanks!

cb