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Synthespin file:   SYNTHESPIN.pdf 000060   5/5/103 8:50 pm
This is taken out of an older book on synthesizers and features primarily projects and modules from PAiA electronics in Oklahoma.

The Synthespin was one of their first effects projects and attempts to simulate a Leslie Speaker effect by modulating the centre frequency of a bandpass filter with an LFO. For whatever reasons, the designer John Simonton, was fond of using LM3900 quad Norton amplifiers where many would use op-amps nowadays. The 3900 is still available. It just throws people off when they see that diode stradding the inputs.

Note the use of voltage-control inputs. Quite advanced for its time, but typical of PAiA style.

Nashville Tele mod file:   NashTele.jpg 000059   5/5/103 4:49 am
A closeup of a "Nashville Tele" mod that I did on a recently purchased Jay Turser Tele clone from their "Vintage Series." I suspect the "vintage" part consists of using a 3-barrel, rather than 6-barrel bridge, a skunk stripe on the neck, and a kind of more butterscotch colouring on the neck.
This one set me back $180 Canadian, has just about the worst fret finishing I've ever seen, and uses what is obviously garbage wood, but it is delightfully light and resonant.

I modded it by installing a homemade Strat pickup in the middle position, and cutting a pickguard to suit it. The pickup cutout on the pickguard is a little wider than I needed it but it isn't too ugly. I used some plastic sheeting I picked up at a model train store for $5. Machines very easily and buffs up nice too.

If you are pondering doing this yourself, note that middle pickup is straight rather than tilted and is centred between bridge and neck pickups at the treble side.

I wired it up to a 5-way switch that gives me neck, neck+bridge, bridge, bridge+middle, and middle pickups. So I get all the Tele settings, plus 2 of the Strat settings. It is a simple wiring trick that involves wiring up a 5-way switch as you normally would for a Strat, but reversing the leads for the bridge and middle pickups, so that the one gets soldered to where the other one usually goes. Takesd a little getting used to your "lead" pickup being in the middle switch position, but worth it to get Tele sparkle and twang and Strat cluck on the same guitar.

T-tone mini-amp file:   T-tone.jpg 000058   3/27/103 11:23 pm
This is a mini-amp so unbelievably cute and coy, I couldn't resist posting it. You know how you're shopping for other things and you stumble across a potential enclosure and you think "This would be so cool"? Well, this is one of those times. The box was 59 cents, AND it came with teabags so I could relax with a "cuppa" once I was done.

Super Octaver file:   SuperOctaver.ZIP 000057   2/11/103 8:41 pm
This is a rarity - a single unit that provides octave up AND down.

As an octaver, it is decidedly a step or two up in terms of complexity, compared to most octave boxes. Although the schematic only indicates the three pitches (fundamental, octave up, octave down), it is potentially expandable to other intervals, though you need a bit of knowhow.

Some of the components may seem unfamiliar, but they are easily substituted for. The 1N60 diodes can be subbed with 1N34 or 1N270. The other diodes are easily replaced with 1N914/4148.

You will note the presence of a DC-to-DC converter, and FET-based switching.

The document is in Japanese, but the technical information is straightforward enough if your Kanji/Kana skills are not up to par.

As with anything on this site, by the time scans are cropped, tweaked, and printed out again, the scaling of the PCB layouts may not be precise. You may have to rescale to produce a Press-N-Peel layout.

The zip-file with all pages is 1.2meg in size, and scanned at 200dpi.

Chaos Fuzz file:   Chaos.gif 000056   1/29/103 6:54 am
A simple, cheap over the top metal kind of fuzz. Very broad range of tones. Very simple perfboard build. Worth trying out if you have an evening to kill.

Phaser to Phasefilter mod for Small Stone   000055   1/13/103 4:34 am
This shows where to modify Francisco Pena's Piedrita layout (Small Stone Clone with CA3080s instead of CA3094) to turn it from a Small Stone Clone to a phasefilter clone.

Two mods are shown. One is forlifting the straight signal, which will provide a phaser/vibrato option for the Small Stone. The other turns the 3rd and 4th stage into lowpass filters instead of allpass.

(JUNE 02 - I have just found out that I put the X for where to cut at the wrong spot on the layout. The GIF file will be repaired and replaced, but has been removed for now. If you did this mod and found it absolutely useless, my humble apologies. Cutting where I indicated actually cancels the phase-shift signal, not the straight signal.)

Another Noise Gate Project file:   LPM-23-NoiseGate.PDF 000054   12/24/102 7:22 pm
This is a project from an older (early 1980's) Japanese projects book. As a design it is pleasantly simple with but two transistors in the audio signal path, and also sufficiently flexible in its' envelope/side-chain extraction that it can be customized a bit. Unlike the other noise gate project at this site, this one will work fine off a 9v battery and fit comfortably in a Hammond 1590BB chassis.

PARTS: The 2SC1000 transistor is high-gain low-noise and can probably be easily replaced with a 2N5089. The LM324 quad op-amp is not part of the audio path so don't bother replacing it with anything to "improve" functioning. If all you have is a TL076/84/64, that will probably work fine. The 2SK30A-Y FET is common enough, but can probably be replaced with the usual suspects (2N5457, 2N3819, MPF-102). Just keep an eye out for pin equivalents. The zener diode (RD5A) would appear to be any 5.1v zener, and the 1S1555 can be replaced with any standard silicon signal diode (1N914/1N4148).

MODS: It is often helpful to be able to adjust the degree of gating/attenuation so that the beginning and tail end of notes doesn't get shut off too hard. To add this function on the project, insert a 100k-250k variable resistor/pot between the source of the FET and ground so that you can adjust the amount of resistance posed by the FET/pot combination in parallel with the 470k resistor. As the pot value/setting is increased, making the FET turn on will still provide only moderate volume reduction. (The FET remains "on" until a note occurrence turns it "off")

The attack time can also probably be altered by varying the value of the 1k resistor after the envelope follower. It is currently set to produce a 5msec attack time, which is fine for most uses.

The 33k/10k-pot combination at the bottom provides a reference voltage for the comparator built around that op-amp. If your guitar provides a signal at the point where you insert this gate that does not let you use the Threshold pot's rotation easily/precisely enough, you can consider changing the value of the 33k resistor so that the reference voltage seen at pin 6 is higher or lower in range. A good strategy is probably to replace the 33k resistor with a 24k-27k fixed resistor and a 10k trimpot. The trimpot's wiper goes to pin 6and provides a bit more or less linear resistance to each leg of the voltage divider currently formed by the 33k/10k values.

SIZE: The scan appears to be about 5% or so smaller than scale, so be careful to rescale the PC layout beforehand if you are going to photocopy to Press-n-peel.

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