My '77 Dyna Comp Clone Build Progress

[Steve Mavronis]

Just a pic I took tonight while test fitting the IC and the five transistor sockets plus the trimpot to my custom layout PCB after drilling holes in it:



It's going to be housed in a red powder coated Hammond 1590B (red=1590BRD) with 1" MXR knobs that will look like this concept mockup illustration below. My clone is based on an MXR factory schematic from 1977 without any circuit mods - just 100% vintage Dyna Comp. I guess it's time to order parts for the hardware and pray that it works after the build is complete!

[Steve Mavronis]

I need to solder 17 vertical mount resistors to this PCB and I want to bend their leads so they all look identical and leads spaced 200 mils (2/10ths") apart. I already know how I'll make the actual bends in a consistent way. My question for a second opinion of which vertical resistor lead shapes in the illustration below do you think would be the best?



I kind of favor #2 and #4 the best. I know #1 would be by far the easiest but some components like the trimmer and tantalum caps will be almost against a pure veritcal lead out of an adjacent hole. Lead shape #4 would sit in the PCB nicely for soldering. The grid dots are 1/10th an inch apart for scale. I'll have slightly over a half an inch space bewteen the pot mounted PCB and bottom lid so vertical components are no problem.

[Steve Mavronis]

Never mind. I practiced after work and got a reliable system down to make consistent vertical resistor lead bends like option #2 using my round nose pliers in exact spots. I was surprised they hold place pretty good on the PCB for soldering. Everything's packed pretty tight so I want a good look with those 17 resistors standing up. Here's an (unverified) PCB parts layout so you can see what I mean:

[Galego]

I usually bend them like this:

[Steve Mavronis]

I finished populating the board and my enclosure holes got drilled today! Thanks goes to Rick Holt (Frequency Central) and Pete (Scruffie) for donating rare versions of the RCA CA3080 (Metal Can and DIP-8) Operational Transconductance Amplifier for use in my DIY project. If this first Dyna Comp clone works I'll build myself a spare using Pete's IC chip too for comparison and backup. I hope the Dyna Comp clone (on the red box) works after I wire the guts up. Here are some fresh pics:





The PCB on the black box is just another 'anniversary' build of my gray 250 Overdrive clone, slightly trace revised but no circuit changes. I tend to build two pedals at the same time. I guess if the red one fails I won't feel too bad with at least one working build to count on

Here's a revised PCB layout for the '3080' Dyna Comp clone:

[ronh95]

Looks great! Be interested in hearing how it sounds...

[Steve Mavronis]

It's not done yet but this is what it will look like...

I just got finished applying the ID-Mark aluminum label and bolted everything through the holes as a dry test fit. I think it's looking nice but just praying I didn't make any PCB layout mistakes and have to redo another board design. Before I do the wire routing inside I'm contemplating making a nice little wiring harness using header pin connectors to be able to disconnect the DC jack and PCB If wanted. Probably overkill, I dunno.

[Steve Mavronis]

Damn - It actually works!!! 

Just finished wiring it up. I was almost going to wait in case it failed but now I can sleep easy. It's like 3:30am and have work in the morining so I'll give it a more thorough test Friday evening and upload a gut shot etc. in the pictures section. I haven't tried adjusting the trim yet but didn't notice any distortion. I've never used a compressor before so this effect is new to me. Good night...

[frequencycentral]

Congrats Steve, beautiful build. And I know how much research you do for each and every build. Glad it's finally alive, and I am proud to have donated a vintage metal can CA3080 to such a great looking build.

[Steve Mavronis]

Glad it's finally alive, and I am proud to have donated a vintage metal can CA3080 to such a great looking build.

Thanks like I mentioned a few posts back to both you and Scruffie for the CA3080 donations. It does look sweet with the metal can like the old script Dyna Comp had. After I get used to my first ever compressor pedal a bit, I plan on making one more as my backup copy and use Scruffie's chip in that one so it won't go to waste.

Next I need to see if I like my pedal chain to be guitar>compressor>noisegate>overdrive>amp or guitar>noisegate>effectsloop>compressor>overdrive>noisegate>amp if you know what I mean.

Thanks again to both you guys. You helped bring this project to reality and inspire me by the great work you all do!

[Fender3D]

Metal 3080 deserves these e-Line transistors http://it.mouser.com/ProductDetail/Diodes-Inc-Zetex/ZTX1049A/?qs=sGAEpiMZZMtvtNzZ3W%252bLwIJv96pYoEwTR6MrzYA5hos%3d