madbeanpedals::forum

Projects => General Questions => Topic started by: dwstanford on November 22, 2011, 08:50:50 PM

Title: Dirtbag
Post by: dwstanford on November 22, 2011, 08:50:50 PM
Well, i dont mean to be a dirtbag, but i already have a few dumb questions regarding the dirtbag delay:

1.  I'm trying to figure out how im gonna get it into a 1590bb and i am having a bit of trouble figuring out where i can put the road rage board.  This thing is gonna be tight as it is. Also, im not sure if putting it in a certain area might cause unwanted noise, etc.  Would it be better to opt for a larger enclosure like a 1790ns or a 125bb for instance?

2. Will i need to use a dc jack with an external nut?  Because it looks like i may not have room for an internal one.  Maybe im wrong.

3.  If i mount the resistors on the back side of the board, should i have enough clearance to get everything in height wise?  I think my tallest component on the front of the board will be about 13mm.  I did an estimated measurement and it looks like it might barely make it.

I guess all these issues could be fixed by going with a larger enclosure, but i would like to make it as small as possible.

4.  I noticed my trimpots are too large for the board. (10mm). Are there certain trimpots that are recommended?  I have a few trims from tayda that seem like the right size.

Thanks for the help.

DS


Title: Re: Dirtbag
Post by: jkokura on November 22, 2011, 09:48:52 PM
Danny,

1. I would put the Road rage underneath the board. If you use PCB mount pots the board will 'float' in the air a bit. I bet if you're smart you can mount the road rage to the enclosure using some double sided foam tape, and there will probably be enough clearance.

2. Probably yes, but it depends ENTIRELY on where you drill the hole. I recommend you drill carefully and slowly, and only after you have the board and an enclosure in your posession. Actually, a good idea would be to make a fake enclosure from some cereal box cardboard. Make holes in that for the PCB mount pots and then drop the board in there and see what the clearance is like.

3. I'll jump right in and recommend that you use a 125BB. It's exactly the same foot print of the 1590BB but it's about 3/8" taller, meaning that it's got enough clearance for you to not have to worry as much about clearance. You might not have any issues with part heights, or jack locations then. Check it out just to ensure that's true though.

4. 3/8" or 1/4" trimpots are usually the DIY standard. It looks like 1/4" are employed here. I think Mouser is a good bet for those ones.

Jacob
Title: Re: Dirtbag
Post by: dwstanford on November 22, 2011, 10:36:29 PM
Thanks for the help, Jacob.

I'm definitely gonna go for the 125b.  That'll give me enough clearance for the road rage and the dc jack and it'll fix all my issues except the trimpots, but Ive found the ones i need on mouser.


Also, can i use the old road rage board or is the new one better for this build, or is there any difference?

Thanks

Danny
Title: Re: Dirtbag
Post by: gtr2 on November 23, 2011, 03:32:01 AM
These are the same bourns trims that mouser sells but much cheaper!  This is what I used for the dirtbag.

http://www.taydaelectronics.com/servlet/the-Potentiometer--fdsh--Variable-Resistors-cln-Cermet-Potentiometers-cln-3362P/Categories

Josh
Title: Re: Dirtbag
Post by: madbean on November 23, 2011, 05:47:33 AM
Yeah the 3362 is the standard size trimpot for all the madbeanpedals projects. When possible, I include extra space around the trimmers to allow for 3/8" but obviously this is not the case with the DirtBag. It's just too compact.

It does not matter if you use the old Road Rage or new one, but the new one does allow you to more easily flat mount a t0220 regulator which is the more ideal one in this case. The regular transistor sized regulators usually top out at 100mA for current supply which is already greater than the current an LT1054 can supply.  But, the t0200 ones are generally rated up to 1A and offer better regulation. These are the same package type as the LM317 ,if you are familiar with those.

As far as height and fitting, as long as you are not using electrolytic caps much taller than 11mm then it should fit with relative ease. It is tight, to be sure, but do-able. For the DC jack, you can try other placements than the one I put in the drill template. Since you won't be running this thing off battery, you can use one of these, which is a smaller, snap in type jack (I use these for everything since I never use batteries):
http://www.mouser.com/ProductDetail/163-1060-EX/?qs=sGAEpiMZZMu2f9RNbWupYnIgpIEIrT90cxuQB4NBfZ4%3d

These have a smaller footprint than the standard 2.1mm jack.
Title: Re: Dirtbag
Post by: TNblueshawk on November 23, 2011, 07:08:57 AM
Dw; you have the option of a 1590bb Tall that would give you the 125b height in a larger size as a possibility.
Title: Re: Dirtbag
Post by: jkokura on November 23, 2011, 07:24:12 AM
You both misread I think.

I mentioned the 125BB which is the height of a 125B but the width and length of a 1590BB. The 1590BB Tall is taller still.

Jacob
Title: Re: Dirtbag
Post by: madbean on November 23, 2011, 07:33:55 AM
I'll upload a pic of how I have my enclosure set up here in a bit.
Title: Re: Dirtbag
Post by: dwstanford on November 23, 2011, 07:46:25 AM
It would be cool to see some pics with the new layout.  I think ive just about got it figured out to fit in a 1590bb which id like to use since i already have some, but i might order a 125bb just in case.  Im gonna pick up a new road rage too just to be sure everything will fit. 

Thanks guys.
Title: Re: Dirtbag
Post by: jubal81 on November 25, 2011, 08:59:12 AM
I'm having trouble locating the CD4047BCN. The part listed at SmallBear is just 4047. Would that work?

Also, I asked in another thread, but I'm wondering if using TLC2272 in place of TL072 would be worthwhile.
Title: Re: Dirtbag
Post by: jkokura on November 25, 2011, 09:10:30 AM
Yes, the 4047 is the same thing.

As for the Op Amp, it depends on what it's being used for. You could socket that one, and tell us if you hear a difference.

Jacob
Title: Re: Dirtbag
Post by: madbean on November 25, 2011, 09:37:17 AM
Quote from: dwstanford on November 23, 2011, 07:46:25 AM
It would be cool to see some pics with the new layout.  I think ive just about got it figured out to fit in a 1590bb which id like to use since i already have some, but i might order a 125bb just in case.  Im gonna pick up a new road rage too just to be sure everything will fit. 

Thanks guys.

Not in the shop ATM but I will do my best to get some pics today. I realized last night that I drilled my DC jack on the left side of the enclosure which was a bad choice. Gonna have to see how to refit it. Gah. I have about 4 builds with finished enclosures waiting to be put together but something else always comes first, ya know?

Anyway, it WILL fit in a 1590BB--I designed it right to the specs of the enclosure. But, I should try to do a more precise drill template for people.
Title: Re: Dirtbag
Post by: jkokura on November 25, 2011, 09:42:44 AM
Another good bit of info is to know if it's chorus with the switch up or down?

Jacob
Title: Re: Dirtbag
Post by: madbean on November 25, 2011, 10:54:35 AM
Down should be Vibrato.
Title: Re: Dirtbag
Post by: dwstanford on November 27, 2011, 01:25:31 PM
With the delay pot, the closest to 100k i have is a 97k and a 103k.  Is it better to be 3k over or under? 
Title: Re: Dirtbag
Post by: jkokura on November 27, 2011, 01:33:59 PM
I would bet that over would give you a slightly longer delay time.

Jacob
Title: Re: Dirtbag
Post by: Scruffie on November 27, 2011, 04:19:47 PM
Quote from: dwstanford on November 27, 2011, 01:25:31 PM
With the delay pot, the closest to 100k i have is a 97k and a 103k.  Is it better to be 3k over or under? 
Probably wont be a noticeable difference but yes 103k would give you a slightly longer delay time, but is your 240pF cap exactly 240pF and your 5k6 resistor exactly 5k6? They all play a part in the delay time.

The only issue that could arise is whine at higher delay times but that probably wont happen.

Go for either!
Title: Re: Dirtbag
Post by: dwstanford on November 27, 2011, 07:07:11 PM
I just noticed i didnt order a 27p cap for c2.  Doh!  Could i sub a 22p or 33p, or should i get one thats exactly  27p?
Title: Re: Dirtbag
Post by: Scruffie on November 27, 2011, 07:09:01 PM
Quote from: dwstanford on November 27, 2011, 07:07:11 PM
I just noticed i didnt order a 27p cap for c2.  Doh!  Could i sub a 22p or 33p, or should i get one thats exactly  27p?
Either would be fine.
Title: Re: Dirtbag
Post by: dwstanford on November 27, 2011, 09:05:32 PM
Thanks.  I appreciate the help.  Im sure i'll have lots of other issues as we go along, so hopefully some of it can help someone else.