Anybody Tried The New Tonepad Digital Reverb Project?

[rhys]

Uses a surface mount chip.  Looks pretty interesting.

http://www.tonepad.com/getFile.asp?id=122

[Morocotopo]

Are you up to SMD soldering?

That´s the main problem I see... so I don´t believe we´ll see many build reports on this one, however attractive the idea of a DIY verb/delay/etc pedal may look.

Morocotopo

[Mark Hammer]

The small amount that I have done has persuaded me that working with SMD chips is not as hard as one might think.  SMD passive components, of course, are a whole other thing.

Make sure that the board is nicely tinned and dab a little bit of liquid flux on the pads and on the "pins" of the chip itself.  Then you can "sweat" the chip onto the board (i.e., heat the pad and the solder flows to the component lead).  The tricky part is holding the chip steady in alignment with the pads.  I imagine one way of doing so is to place the board in one of those "third hand"  vices that use alligator clips to position the board.  Use a pair of small neodymium magnets, one on top of the chip and another on the other side of the PCB to secure the chip in place.  The nice thing about this is that you can still manipulate the chip a bit to make sure the pads and pin are perfectly lined up, plus the magnet acts as a bit of a heat sink.  Once you have a pin and pad sweated together on each corner, you can remove the magnets and sweat away.  It is probably a good practice to keep a magnifying glass handy, and to leave a little bit of time between when you do a couple of pins and the next couple of pins so that the heat does not build up

[head_spaz]

I might be interested in this project. Haven't had a chance to study the data sheet yet, so it basically will depend on whether or not programming is required for basic functions. I'm no good at programming.
The board looks pretty nifty. Minimal SMD, and that's a good thing for us old geezers.

[Mick Bailey]

I've had few problems with SMD so long as the soldering iron tip is fine enough. The solder also needs to be thin, otherwise you can end up bridging the pads. If you only have a few pads to solder, get your standard cored solder and gently hammer it on a smooth surface while rotating it to get a finer inch or two. Flattening it slightly also helps.

If you tin the pads and component leads first another way of locating the part is to place a tiny blob of adhesive under the device (making sure it doesn't contaminate the pads) and press it down until it sets. Then apply heat to flow the solder.

The main problem I've found with SMD is removing components. I've been to a workshop where they deal with SMD all day long and they have loads of different hot air and other devices to melt all of the connections of a component simultaneously. They remove them with a little vacuum sucker. No damage either to the component or the board.

The reverb circuit looks interesting, but it's not clear if you need to include the switches off-board, or why there are trimmers on the board and not external pots. A quick look at the spec sheet suggests that the other internal programs may be interesting and accessible (though it does not recommend these for actual use - they seem to be demos). Could be a nice circuit to build in the same housing alongside a Rebote delay

[Fp-www.Tonepad.com]

Solder wick, flux, tweezers, magnifying glass.

I think that's about all you need for smd ICs.

And a tip I picked up somewhere: only solder 1 pin of the IC until it's perfectly aligned, you can adjust orientation by flowing the solder on that pad and moving it with tweezers, once aligned solder the rest of the pins. Remove bridges with wick. Reflow solder by adding flux when needed.

Solder mask helps a lot with this technique, I hope to have boards for this project available in just a few more days.

[MetalGuy]

Solder wick, flux, tweezers, magnifying glass.

I think that's about all you need for smd ICs.

Maybe you should consider selling the boards for this project with the chip presoldered.

[CGDARK]

Check this video and give it a try.

http://blog.makezine.com/archive/2007/03/smd_soldering_video.html

CG

[any]

Haven't tried smd parts soldering yet but will give it a go soon, this project is interesting...

A tip I heard that sounds easy, is to use a small drop of 1 second glue to glue components to the board.
After that you can solder all you want without stuff shifting around.

[Fp-www.Tonepad.com]

I built it successfully, it works great as it is in programs 0 to 4, programs 6 and 7 will need extra circuitry to mix the dry signal. Excellent presets.

And please note: there are a couple of errors in that schematic, pinout of fets are backwards, the two 1uF's at the input of the FV1's are backwards (polarity is wrong on the pdf), and maybe something with the regulator also. I have made all the required corrections in my printed page, but won't be updated to tonepad until next week, I'll be out this weekend to go to Nashville for summer namm. (anybody around that wants to meet shoot me a private msg)

As for the smd, I suppose I could offer some boards with the chip in them, but i need to look into it further.

Fp

[ClinchFX]

I had to learn to work with SMDs at 50+ years old.  It was a matter of adapting to new technology and remaining employable.  I now find it much quicker and easier to work with. I use SMT on veroboard for nearly all my prototyping. The only specific SMT equipment I have is a hot air reflow station, but it's just as easy to use a butane powered hot air torch. At work, a couple of years ago, I had a tweezer iron, but it was only useful if you had to remove a lot of components in a hurry for major rework.

I consider a temperature controlled soldering iron with a fine tip to be a necessity, but I expect that anyone who is really serious about working with electronics will have a good iron.  Good lighting is also a necessity, as it is for any electronics workbench.  As a concession to the fact that eyesight deteriorates after about age 30-35, I use a magnifying hood.

Peter.