Russian Small Stone - is the design different?

[Mark Hammer]

I picked up a Russian Small Stone today for $30.  I'm up to my eyeballs in phasers, so I didn't really need it, but it looked so lonely (and butt uuuuhhhhhhhhg- LEEEEEE), and the box is so big that there is room for any kind of mod a person would like to stick in there.  Heck, I could even stick in more stages and a switchable distortion stage for that matter.  A lotta real estate.

It looks more or less like an Issue J but with a different layout.  Does anyone know if it is identical to the Issue J?

[Mark Hammer]

Never mind.  Pretty much figured it out.

Dead easy to implement the phasefilter mod on this one.  Also learned that if you split out the color switch into its two functions - width/shape and regeneration amount - via two separate toggle switches, it pays to make the regen toggle a 3-position on-off-on. 

You can see here that the stock switch selects between bypassing a 270k fixed resistor, or switching the junction of that resistor and a 0.1uf cap to ground.  If you make the 270k/0.1uf junction the common of the switch, you get one position where the 270k is bypassed, another where the 0.1uf cap is grounded, but a third where the 270k provides feedback to the input, but is not bypassed.  These provide three audibly different regen sounds.  So, splitting the Color switch into a pair of SPDT toggles, one of them 3-way, gets you 6 different settings, instead of the stock 2.  That's 50% more settings than a Phase 100.

[igerup]

You know, resizing the pic (smaller) makes it a bit easier for everyone...

[Mark Hammer]

Sorry abut that.  I linked to the first reasonable picture I found in Google, without realizing how big it was.  Guess it pays to preview posts, doesn't it.

[StephenGiles]

You know, resizing the pic (smaller) makes it a bit easier for everyone...

It depends how tired your eyes are - great size for mine

[Mark Hammer]

Ended up sticking with 4 switches - sweep width, phase/phasefilter, regen amount, vibrato (dry lift), and a speed pot.  Probably could have added more, but this was the biggest sonic return for the least work.  With a 3-position regen switch, and two positions for everything else, that gets me 24 different settings plus variable speed, which is quite a lot of variety for so little effort.  Doing the mods was very easy on this board.  Anyone attempting this should note that the Color "toggle" (if that's what they use for switches over there, no wonder they can't put out those fires!) does not have the same lug layout as what most here are used to.  The common is actually off to the side, and what would normally be the two "outside" lugs are right beside each other.  Glad I did a continuity check first before wiring the replacement up or else I would have had a disfunctional pedal.

The main panel was in reasonably decent shape, but the lower/outer part of the chassis was beat to hell, with rust where the paint used to be in many places.  Dabbed some paint stripper on it and scraped off the bad paint easily.  Sprayed a coat of black enamel to replace what was there and baked it.  Sprayed a coat of clear laquer over the top panel just to even out the finish and protect the added legending (white letters against a black background...nice), and the thing looks and sounds great for a few hours work last night.  Now the only thing left to do is figure what to replace the missing battery door with. 

Total cost was about $38 bucks for the pedal, switches, and a new speed pot+knob (the original has a VERY nonstandard shaft size which severely constraints installation of a different knob, and didn't situate the original knob that precisely anyway).

I wish they were ALL this easy and cheap.

Pics-n-sound to follow.

[StompIt]

Hi Mark,

I bought a cheap Behringer VP-1 vintage phaser, based on the SS circuit.
I want to add some mods like true bypass and the sweep width, phase/phasefilter, regen amount, vibrato (dry lift), and speed pot you mention in your last post.
The VP-1 is an SMD-build so I am just figuring out the differences to the SS-schematic (very small tracks...).
There are several schematics around with different numbering of the components. This is quite confusing. Also the VP1 has a complete different numbering.

So could you please provide a numbered schematic with the above mentioned modifications indicated?
This would be quite helpful.
As the VP1 is surface mount and has a large, stable case there is lots of space including modifications.


Thanks a lot,

StompIt

[Mark Hammer]

I have no idea what Behringer numbered the parts as, however the pin assignment for LM13600s (which I gather they are using) ought to be the same for an SMD version as they are for thru-hole version.

I tried moddig my PH9, and while a few things were fairly simple to identify and mod, there was a whole lot that I found impossible to identify and do because of a) use of SMT and double sided boards, and b) a few component value changes that made it difficult to equate the MXR and Behringer circuits in select places.

Exasperating when you see all the space for adding mods but you juuuuuuuussssst can quite figure out the board, isn't it?