Ross 8-stage phaser build report

[jmasciswannabe]

Finally finished it. Used the original layout as well as the add on board layout from tonepad. I had originally planned on making a 12 stage, but stopped at 8 because that was all the phase sound I personally needed. For some reason I had lots of problems with solder traces this time around. I always make my own board and usually have a couple of issues, but this project was plagued with them. Luckily I have made friends with my audio probe and multimeter. Debugging time nearly doubled actual building time! Anyway, on with the mods!!!

- lowered the 27k resistor right after the regen pot to 22k
- replaced 10k resistor between ic1 and ic4 with a 2.2k and a 50k pot wired as a fixed resistor (sweep width control)
- replaced 3.3uf cap that controls lfo speed with a switchable 1uf and 10uf. Slower for the phase faster for the vibe.
- I also added a cap to ground right after the sweep width control to smooth out the top end of the sweep
- univibe switch with typical univibe values
- all pass filter switch
- switch between 4 and 8 stages

Sounds miraculous. No ticking!!! Just smooth delicious phase. The add on board really did it though. I like running it slow with 8 stages with the regen and depth maxed out. WOW!! I no longer lust after the moog 12stage. I really like the vibe settings I can get out of this guy as well. The speed switch definitly makes a big difference as well as the sweep width control. You can get that anoying warble out of it and get a really nice vibe. My favorite, most worth while project yet!

I must first thank FP for making this project available, as well as all the other projects on your site. What a great time I have had with this hobby! If you want to lower your debugging time definitly order some boards from him! Next up is Mark Hammer. All the mods I did were posted by him (though I cant find the thread  where I read about the cap to ground, so feel free to correct me if I am wrong.) The mods really made this phaser what I wanted. Thanks to the rest of the diy posters who answered questions I have asked and posted thoughts on the ross and small stone circuits!

[Mark Hammer]

Congrats J,

This sounds like a highly desirable pedal.

You know those old films you'd see where some sweet young thing was saddled with an ugly life and uncaring husband who couldn't see what beauty and power lay underneath?  Sort of Cinderella married to a brute?  Both the Small Stone and Ross are designs that were simply overlooked by an uncaring, and untutored consumer market.  I suppose E-H *could* have dressed up the SS, but it required a market with more taste and knowledge to appreciate those details, so it always remained dressed in rags with a lowly single knob and switch (the cap to ground on the LFO was from a recent thread about similarities between the first issue SS and the Ross).  Ross dolled it up a bit with two knobs, but really that was just washing the rags, rather than exchanging them for a beautiful gown.

Happily, this group/community here HAS the knowledge and taste, and the resources to access it.  And that puts otherwise pleasing-but-bland effects like the Ross/SS in a position to become the glorious swans they are instead of remaining ugly ducklings. The mods really DO allow these pedals to be sound tools rather than just one-trick gimmick pedals.

I'm also pleased you were so happy with the finished project because I have a similar thing "mostly done".  Unfortunately, I needed to perfboard it to fit in the available space, so that extends build time (and undoubtedly debugging time).  But your comments make me want to see it through to the end. 

Francisco has made it easy to do for many by providing the board layout.  So thanks to Francisco from me too.

Finally, it might be better to make that 2k2 resistor in series with the sweep width pot a little higher, perhaps 3k9 or even 4k7.  I find too small a value makes the "turnaround" at the high end of the sweep too abrupt.

[Fp-www.Tonepad.com]

I am most honored. I couldn't do it without all your support and knowledge!

I have etched boards for myself to replace my Ross Phaser forcefully bought from me by a friend of mine. I can't wait to get  started!!! (Hey, I really love building them too!!)