Dunwich DA-120 on a breadboard

Dan M

Well-known member
Well, this is my most ambitious breadboard.

For new breadboard bakers: Don’t get discouraged when your board doesn’t work. This is a monster with 7 pots, 3 different voltages, 2 IC’s, and 4 transistors. And it was crippled by a missing jumper and an out of place resistor leg. Just walk away, and come back later with a clear head and trace it out.

I saw the strip board layout over at dirtboxlayouts and had the idea to translate it onto a breadboard before committing to build it.

I worked out the schematic from the dirtboxlayout. I picked away at it in the evenings while watching tv. Once I had the schematic figured out, I built the breadboard and of course it didn’t work. :unsure:
Then it collected dust for 2 months until tonight. I had 1 resistor leg out of place and 1 power wire missing.

So after 4 months, here it is. It’s a big ole beast and it sounds awesome! One of the pots is standing in as the internal trimmer, just because it was easier to place. And the FAC rotary is missing (I just swapped the caps by hand to test them out).

I’m definitely going to build and box it. I’m fiddling with ways to board mount some or all of the pots. Or maybe move the schematic to perfboard, if that provides a nicer layout.

5B55DAAE-B8F4-47EF-8BCF-CE17BAB05C12.jpeg
 

temol

Well-known member
I've seen a bit different version. With J201 instead of the BS170, with clean blend. Without FAC switch. From what I remember there are different revisions of the circuit.
 

Dan M

Well-known member
I decided against the available strip board layout because I don’t enjoy off board wiring and wanted board mounted pots.

So I worked out a perfboard layout in DIYLC. Once it’s done and confirmed, I’ll post the layout. It’ll fit in a 1590XX.

I triple checked the layout against the schematic. Then I moved the components one at a time from the breadboard to the perfboard, checking along the way and talking out loud to myself. “Input, 10 meg to ground and 100nF. 100nF to Q1-2 and..and…, etc”

All of the components are placed. Tomorrow I’ll cover it in blue tacky, flip it over and start soldering.

39DA2BC5-4732-45D6-A450-0F4B6C91FC60.jpeg
 

steviejr92

Well-known member
I decided against the available strip board layout because I don’t enjoy off board wiring and wanted board mounted pots.

So I worked out a perfboard layout in DIYLC. Once it’s done and confirmed, I’ll post the layout. It’ll fit in a 1590XX.

I triple checked the layout against the schematic. Then I moved the components one at a time from the breadboard to the perfboard, checking along the way and talking out loud to myself. “Input, 10 meg to ground and 100nF. 100nF to Q1-2 and..and…, etc”

All of the components are placed. Tomorrow I’ll cover it in blue tacky, flip it over and start soldering.

View attachment 32899
I really want to see how this turns out!
 

Dan M

Well-known member
IC1-4,5 & IC2-4 required expansion I see :D
It interesting: When I was working in diylc, it was a challenge to pack everything in. But looking at the picture, the board appears to have a bunch of wasted space.

Ultimately, I didn’t see how to fit it into a 1590BB. When I moved the footprint up to 1590XX, I had enough room for a symmetric layout with 5 knobs in the top row, then Volume and Boost on the bottom row.

The board is soldered. Later today, I’ll test it, see that it doesn’t work, and drink a beer.
 
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