Messages

Marvin,

I'm getting all orders out today, which will let me work on that tonight. I will do my best to have the fix posted here tomorrow.

Thanks for you patience--I know it is taking a while.

Brian

A relatively easy way to do this is to use a charge pump to put out 9v+ and 9v-. That way you could use a single 9v supply to power both at once. You can find some more info about this and probably other methods on diystompboxes.com. There are a lot of threads about it. If you want a board for it, I could make one for $1. The Road Rage 2 is going to have exactly this (+,-9v) as well as the ability to run regulated 12 or 15v all off the same tiny board.

If you use good soldering methods you don't need a heatsink. Of course, it doesn't hurt, but it can be time consuming. There are two different methods to try, depending on what type of circuit board you are working with.

Manufactured boards are more difficult to remove parts from because they are generally plated through the holes, which means they soak up a lot of solder. And, if the build is pretty old, the solder will most likely have oxidized and become pretty cruddy. This means more heat to remelt and remove it. That increases the chance of burning a part up. In practice, I have never burnt a single part due to desoldering, but I've definitely ruined some pads. If you are not going to be re-using the circuit board, then that doesn't matter--you can pretty much destroy it getting the parts out.

Anyway, if you are working with that type of board, a desoldering pump might help. You can get them at radio Shack for less than $10. Basically, you just heat the top side of the pad and use the pump on the other side to vacuum up the solder while it's melting.

I usually use solder wick for desoldering because it is easy to work with. You first heat up the solder joint then apply the wick with the tip of your soldering iron. The solder will get soaked up onto the wick and clean the joint out. Sometimes you actually have to add a little solder to the joint first to get it flowing.

If you are careful, and take your time, you should be fine. Just remember to keep you iron on the joints for 10 seconds or less to prevent overheating the component. If you wait 15 seconds in-between then it wil cool off enough so you can hit it again with your wick until it's all gone.

Parts help with a different fuzz please.  The Zygote Mojo.

When I order germaniums from smallbear will I have to wait until the parts arrive to know which resistor values he recommends?

Also, the 20uF sprague you recommend in your pdf is on back order at mouser.  Another 20uF Sprague of similar attribute ( TVA1305.5 ) is available.  Can I substitute that one, or will the higher voltage rating/or other be problematic?

thanks

You don't necessarily have to us the resistor values he puts in. The circuit will bias with the trimpot. So, for whatever value he suggests for R3 (my schem) I would adjust the trimpot to approximately that value before soldering it on. You will have that 100R in series with it, so after you fire it up measure the voltage on the collector Q2 - you should read around -4.5v with a fresh battery. If not, just play with the trim a little bit. Anything between -4.5 and -5.5 volts will sound great.

As far as the other resistors he lists, you can use the closest approximate value you have. Those values are less important--the main thing is getting Q2 biased correctly.

For the Sprague--you can certainly use the 50v version there. The stock value for the circuit is 22uF. I chose the 20uF Sprague mainly for mojo. You could just as easily use a Xicon 22uF axial there if you want.

I think fuzzes are much more personalized builds so component types a values can vary greatly. Luckily, they are so simple to work with that it makes it easy and fun to try different parts and values throughout the whole circuit.

1) Can I just substitute chips like NE5532, LF353N, and JRC4558 without performing any additional mods?

- Yes

2) Could I use a NJM4560D IC in it?

- Yes

3) How about op-amps that are single-supply rail-to-rail?  Can a chip like the OPA2340PA  go in there?

I don't know much about these, but I think so.

4) I've also read about the TL2272, but I have yet to see it for sale anywhere.  Anyone have a source for those?

It's actually TLC2272

5) Also, I have noticed there are different versions of some chips offering different "Rejection Ratio" and "Input Offset Voltage" values.  For example, this is the result of a search for LM1458 on Mouser's site.  How do I know which one to buy (for Neutrino)?

Actually, when you reduce the search to only PDIP packages, you only get one result:
http://www.mouser.com/ProductDetail/Fairchild-Semiconductor/LM1458N/?qs=sGAEpiMZZMtCHixnSjNA6DVd3Z3DRNoF1byePuYBjeY%3d

In general, the smaller the offset voltage, the better.

Needs one of those little stickers that voids the warranty if you take the lid off.

I've only used 4580DD's. Having compared that side by side with an actual KoT I can tell you the difference is negligible.

Yep, that's the one.

They'll push in. It will wear out your BB a little more, but mine is still going strong and I've had it a few years.

Gotcha. This is the one you want: the "EZ":

http://www.newark.com/intersil/ca3130ez/operational-amplifier-op-amp-ic/dp/80K5721

One other thing: the next few batches of orders will not be tinned with the Liquid Tin solution I've been using recently. I think my batch got contaminated and it's producing crappy results. I'm going to look into some alternatives for tinning to see if there is something other than a solution based method. I know Barry (my7of9) uses a spray, so I may check that out. If I can decontaminate the liquid I have, I'll keep using it.

All orders before 3/31 have been shipped. Thanks everyone for their patience and support while we dealt with our little crises here. I'll have orders from 3/31 through today out by Thursday morning.



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Are you sure you aren't looking at the open vs. closed loop ratings for the slew rates? Can you link me to what you are looking at? Thanks!

The rig has changed quite a bit since I took this pic. The newer version has only the breadboards and a 1590A which is hooked up just like a regular pedal without a circuit. I'm also using PCB mounted pots now instead of that aluminum sheet. It's just quicker to pop in the pots that way.

As far as your questions:
1) You should, at the very least, have something set up so that you can test your builds out before boxing them up. It is imperative that you do this. There's nothing worse than spending an hour boxing it up only to find out it's not working. By testing it first, you will save yourself a lot of frustration. It can be as simple as to mono jacks and a battery snap on a single breadboard, so you can run power and plug into the effect and amp.

2) The cutting board is about 10x8. I got it at Target, I think.

3) As many as you can afford. I have regular lug pots that I use for builds that I'm actually going to box, and PCB mounted pots for prototyping. It's up to you if you want to go through that expense, but having at least two of the most common values will save you time: 1k, 5k, 10k, 25k, 50k, 100k, 250k, 500k, 1M.

4) I got the sheet from a local hardware store. I drilled all the holes first, then scored one side of it with a knife and then bent it into shape. I also sanded the edges some to round them off. It was purely to mount switches and pots. don't worry about shielding. BB's are noisy and you will find most effects quiet down a bit once they are in an enclosure.

5) The bracket was supposed to mount a little coffee can amp which I never got around to building. Turned out I much preferred plugging into a real amp when testing things out!


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It is a jumper. That was a poor choice on my part as far as labeling. In the next version it will be pictured as a jumper, not a resistor.