'77 Dyna Comp Clone Project

[Steve Mavronis]

I'm building myself a clone of a 1977 Dyna Comp based on an actual MXR factory schematic. I've already created a viable (but unverified or tested) PCB layout using ExpressPCB. Luckily my father does electronics etching professionally and makes my boards for me (as with my finished Neo-Classic 741 Overdrive '1979 gray spec' 250 clone) plus they are tinned using electroplating. I'll share the PCB trace pattern with everyone after I prove it works so you don't waste your time etching it incase it has an error. Oh and if you do it the PCB mounted pots are optional and you can use wired connections instead to your liking. Here is a screenshot showing part locations and values. It fits on a 2"x1.7" PCB inside a Hammond 1590B enclosure:



Well I've been through many graphic concept ideas so far but trying a new theme with this scale graphic mockup done in GIMP software. The top panel aluminum areas represent the etched ID-Mark 0.007" thick adhesive metal panels that I use for labeling. The dragon head graphic is a free font from the 'dafont.com' website. The circle border is added separately in another layer. I like using font's for graphics because they are vector scalable and don't loose resolution. I recommend anyone doing pedal graphics to try these special character fonts. I have artistic skills and could hand draw graphics but using scalable fonts is a time saver.

Trying a new theme yet again. The dragon head graphic is a free font from the 'dafont.com' website. The circle border is added separately in another layer. I like using font's for graphics because they are vector scalable and don't loose resolution. I recommend anyone doing pedal graphics to try these special character fonts. I have artistic skills and could hand draw graphics but using scalable fonts is a time saver.

I'm not sure if I like the 'Dragon Attack' name but using compressors does affect ones picking attack while playing. Here's versions with a 5mm LED and with 3mm and plastic LED holder.



Let me know what you think. The main thing I like is using the LED as the dragon's eye.

[nbabmf]

Are you making any substitutions for those transistors?

[Steve Mavronis]

Are you making any substitutions for those transistors?

What are the functional equivalents or closest thing to the specs of these transistors as used in the 76/77 MXR Dyna Comp?

SC 1849
MPS 5172

I think the later is still available, or it might be the other way around. Not sure but I need to source these soon before my build. I already have a 3080 Operational Transconductance Amplifier that I'll need too.

Thanks.

[nbabmf]

Just about any run of the mill, general purpose NPN transistor will work. I have some metal can 2N2222's in my Ross compressor, which is a juiced up Dyna Comp. Since the 3080 is doing all the work, you don't need to track down anything special.

SC 1849 = 2SC1849

Those are pretty easy to come by. I'm pretty sure my "transistor grab bag" from Futurlec had about 20 of them.

[Steve Mavronis]

This is just a "test screenshot" trying my old Neo-Classic theme and a dragon tribal tatoo graphic. I don't like how it doesn't fill the space more but there are plenty of other graphic ideas to try and not just dragons!

[McSpunckle]

Also, it looks like the dragon is wearing a monocle. Which, actually, is kinda awesome.

[Steve Mavronis]

Also, it looks like the dragon is wearing a monocle. Which, actually, is kinda awesome.

Haha, actually the graphic is kinda of a placeholder until I figure out what to put there for real. I was more trying the font style change to fit in with the look of my last pedal. But I can't use a schematic graphic of the whole pedal like before because this one is several times more complex than a simple overdrive circuit. BUT, looking at the relatively simple internals of the CA3080 operational transconductance amplifier (the 741 op amp internals is much more complex) it might be possible to revamp this into an interesting cover graphic similar to what I did with my Neo-Classic 741 Overdrive:



I'll re-work on it tonight in ExpressSCH and see if it would fit onto the pedal.

[Steve Mavronis]

Well the 3080 schematic didn't work out so well 'yet' but I kind like using the shield as the LED on this Greek calvary warrior. I added the arm with spear from part of another font in the same set:

[The4455]

Well the 3080 schematic didn't work out so well 'yet' but I kind like using the shield as the LED on this Greek calvary warrior. I added the arm with spear from part of another font in the same set:

The graphic doesn't matter if you can't build the pedal, enough pictures, let's see the final product, and a video of it in action.

[nbabmf]

OH SNAP

[futuresailors]

[Steve Mavronis]

My dad stopped over tonight and brought me the aluminum panel etch of my pedal artwork labeling:



It was hard to get a straight on photo because of glare from artificial lighting in my house but i think they turned out really nice. Next he will bring me my PCB etched and I need to order my enclosure, pots, knobs, and other stuff I still need! Then I can move on to the workbench phase.

[Steve Mavronis]

It's not quite done yet but this is what it will look like... (before anyone asks, it's not going to be for sale. It's a DIY build for myself because I want a comp pedal)

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.



I hope the Dyna Comp clone (on the red box) works after I wire the guts up.





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

[The4455]

Awesome, both of the pedals you've built look profesionalyl done, adn bitch'n.

[Toonster]

Yeah,. that looks cool! :-)