# Q: EHX Small Stone phaser



## devnulljp (Mar 18, 2008)

Is the old orange lettering small stone a tone sucker? 
Does it have a noticeable volume drop when engaged (and can that be fixed easily enough?) I've seen varying reports, but it's never clear which ones are affected.

(I'm trying to make a buying decision -- this or a Phase 90...)

I used to have a v3, but foolishly sold it.


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## mhammer (Nov 30, 2007)

There are a number of different issues of Small Stone. The earliest one (my preferred one) has six eight-pin CA3094 chips. The second and most common has 5 chips. As supplies of the CA3094 started to dry up, there was a version that used LM13600 chips (one of which replaces two CA3094s). http://electroharmonix.ronsound.com/images/stories/gallery/fake/atak/ss13600.jpg

Here is a pic of early SS pedals: http://www.modezero.com/images0000/small-stones-Ax.jpg

Like other E-H pedals from the 70's, the SS used a SPDT stompswitch. That arrangement produced some loading in bypass, but the circuit was designed around that such that effect and bypass had equivalent levels. Unfortunately, when you convert to truye bypass to get past the tone-sucking, you end up with a slightly lower level in effect than in bypass mode. That CAN be fixed, however, and information abounds on-line about how to do it.

For my money, the SS is a terrifically flexible pedal whose possibilities have remained untapped by E-H all these years. Take a listen to what one guy has been able to do to his SS here: http://moosapotamus.net/THINGS/frankenstone.htm

The phase-filter mod is something that can be done to ANY issue Small Stone, and is a terrific sound that does not currently exist in any commercial pedal to the best of my knowledge. When done right (and the sound clips don't do it enough justice), it provides a combination of vibrato, tremolo, and autowah that is ridiculously swampy sounding and has Daniel Lanois written all over it.

The mod is very easy to do. Looking at this schematic: http://www.freeinfosociety.com/electronics/schematics/audio/pictures/smallstonephasereffect.jpg one would take one end of the .0068uf caps in the last two phase shift stages, and connect it to ground. The end of the caps that goes to pin 1 remains in place. It's the other end of that cap that goes from where it currently is, to ground. Since it only involves routing two components to each of two locations, you can use a DPDT switch to do it.

There's more, but I gotta go do some grocery shopping. I'll just say that the SS has a nicer sweep than the P90.


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## Ripper (Jul 1, 2006)

The volume problem with the small stone was fairly common. It's an easy fix.
Find R6, it's the feedback resistor for the input gain stage. It should currently be a 5K6, you need to change it to a 10K. Then find R27, it is a 2K2 resistor and it feedback and color stage as a mixing resistor. Change it to a 5K6 resistor and you are set. That should cure the volume drop issue. 

I've had some over the years that seemed to suck tone and others that didn't. To true bypass one is also a very easy mod. I've owned enough phasers over the years both the phase90s and the EH's and when it comes to those two, the EH is my choice for sure. If you want a really killer phase pedal check out the one from Diamond Pedals. I've got one and it is the finest phaser I've ever owned or used, hands down


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## devnulljp (Mar 18, 2008)

Thanks for the great info guys. I pulled the trigger, so should have this thing pretty soon.

mhammer, those mods are insane...that thing looks like the guy from Hellraiser. JC Maillet has a similar page up with similar mods too. Now I want to buy a reissue too to mod it...


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