Building: Quad LFO by

I’m waiting for the Dotty boards to arrive. Meanwhile I ordered some other boards and these came in quite fast. has some great modules online. You can download gerbers and information on his site.

I ordered the Quad LFO, Quad VCA, Buffer mixer and precision adder. I think these are some of his latest design. These use thonky jacks where others seem to been build with banana jack. I don’t have banana jack in my rack and tend to keep it that way. Got nothing against banana’s (quite nice actually). For simplicity and not have to stock more part I keep it to 3,5mm mono jacks

The boards are well documented. And I had a lot of fun soldering the first board. As always starting out with the smallest part. diodes, resistors, capacitors. The resistors are place “inline” mostly, except for 1m and 27k resistors. So putting them on to the board makes it a quick job. I got this board almost completely soldered within 2 hours. A still had time to drink a few coffees.

Then I had a good look at the board and saw it wasn’t all through hole part. There are some smd capacitors needed. mostly for decoupling the chip. And following the rule smallest part first, I’ve should have done these first. Not a big problem there enough space to solder them in. (And if you never ever soldered smd this is a nice board to try it out).

Some part in the BOM seem quite “old” or strange to me. I don’t have these in stock. TL064, TL062 BC550. But I quite sure a TL074 and TL072 will do. The BC550 is a Bipolar Transistors – BJT. I have a lot of these but not the BC550. Google searching tells me: You can replace the BC550 with the BC546 or BC547.

Well BC546 I do have. I think they will do. Have to check the hive/experts what the difference are. Maybe will get some “Magic Smoke”. But pin out seems the same will see…

I am missing 3.9k resistors in my drawers. Have these on order waiting to be delivered for a other build (Weston B1 Bassdrum needs one too). So have to wait till these come in.

So most of the board soldered in 2 hours time to have a look at the control board (where the jack and potentiometers are). The controlboard also has a few resistors I can solder on to it. But when soldering the potentiometers and jacks I like to have a panel. This helps align the potentiometers and jack and you can flip the board without have them fall out.

Uhmm Haraldswerk…where are the panels?

Well my bad these are in the documentation zip files. These where made with FrontPanelExpress. Nice software to design panels, but I really don’t like the prices. Let’s make Gebers out of these if possible.

Front panel express can export to dfx. Kicad can import DFX. I exported the files and imported them into kicad layer. I imported the file two times as Silkscreen and Edge layer. Then started removing some part from the Edge layer and some from the Silkscreen

I moved some of Haraldswerk’s text around to fit my own idea. Added some copper lines and hoping this will be acceptable for the manufacturer. In the 3d viewer all looks good but the manufacturer gerber viewer show some strange result, not the first time this happens. So I don’t think it will be a problem. The drill file is empty because all the cutting is in the Edge layer. But will see how the respond. Most of the time they are really easy and provide fixed need themself.

As I order more PCB by haraldswerk I think I have to do this for those others as well. Then ordering the panel boards. so waiting on components and panel this pcb has to move from the bench for now. But can’t wait to finish this.