placing and re-placing effects mid-performance

[angelo]

thanks mark. "wiring it up" real quick sound good to me.

[angelo]

ray,
The preamp is a marshall and I use it distorted and clean. There is a case where the distortion HAS to come before the filter, but I think I am liking your attitude. If it sounds similar, and it wont ruin the song, go with it. That certainly sounds better to me than spending a few months on another project. I should be playing music, not building amps and switches. But that is just the way it goes for musicianeers like us.

thanks alot for the info and the outlook

[Tai]

Epfm2

Actually, there were a fair number of differences.

• Each project included a list of what could be modified to what ends
• Each project included more detailed specs
• The pads for leads generally come out to only one edge on the PCBs in the 2nd edition, and often two sides in the 1st.
• The projects tended to have more control/features built into them in the 2nd.
• The semiconductors tended to be a little more commonly found int he 2nd. E.g., the first used an NE531 op-amp for the treble booster.
• There were more projects in the 2nd than in the first.

All told, the 2nd edition is a better purchase, and happily is still available from many places. I have most of the first one photocopied, and I'd have to say that the brunt of the projects in the 2nd edition are of higher quality, and more instructive in many ways.

If I may ask, what did the 2nd edition use for the treble booster. I have not been able to locate the 531 (without buying quantity). I have the 1st edition of EPFM and am using an LM301 for the treble booster, but am running into problems, so I don't know if it is an exact match. Is the 2nd edition schematic the same as the 1st, except for the change in opamp?
Thanks for your help.
P. S. I wrote to Craig Anderton but he's a busy man and hasn't yet replied.

[Greenmachine]

You may be pleased to find that the oh-so-humble Small Stone Phase Shifter, and indeed any phase-shifter using OTAs can be easily converted to a "phasefilter" to great effect. This occurred to me one day while I was perusing both the SS schematics and the datasheets for the SSM chips. I realized that the long-extinct SSM2040 was just a quartet of OTAs, with many of the same control pins as a 3094 or LM13600.

The conventional circuit ties a cap to the input for allpass stages. If you reroute that cap end to ground, exactly as you see in the SSM2040 phaser/filter in DEVICE (and like the Blacet circuit), you convert the section into lowpass. Do it for two stages out of 4 and voila, instant self-contained phasefilter.

Charlie Barth did this, at my urging, to his Small Stone and posted some sound clips here: frankenstone I don't think the sound clips do it justice, but you can get some idea.

With dry signal lifted, and two of the stages converted from allpass to lowpass, this makes one of the sexiest tremo-viba-phasa-licious things you can imagine. Wihout a dry signal mixed in, the modulated allpass sections make for a gentle vibrato. Followed by a pair of lowpass sections, you get a modulatd wah. Since the two produce a modulated overall volume level, you get a quasi-tremolo (though not true volume modulation). Set for a "Born on the Bayou" or "Baby Scratch My Back" sort of tremolo depth and speed, it is ridiculously seductive and entirely unique. I'm supposed to get together with a fellow who is Sheryl Crow's guitar tech when she comes through town in a couple of weeks, and I'm hoping to get a modded unit to her guitarist, Peter Stroud, to try out. VERY neat effect and not commercially available to the best of my knowledge.

Hi Mark,

Could you please explain how to use two LM13600's instead of a SSM2040?

Thanks

[Mark Hammer]

Look at the schematic for the Ross Phaser here: tonepad -- FX projects

It is essentially a Small Stone, but using a pair of LM13600s instead of 4 CA3094 chips, and an op-amp input and output/mixing stage instead of the discrete transistor and passive equivalents in the Small Stone. Creating a phasefilter sound consists of simply lifting the side of the 3300pf capacitor that connects to the input on two of the stages, and rerouting it to ground. That's it.

And no, Peter didn't try it out...though he did do some emergency repairs to his amp with some mica caps I brought him.

[Greenmachine]

Thanks Mark.