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FX archeology 101: The Guild TriOct

2/1/2001 1:58 AM
Mark Hammer
FX archeology 101: The Guild TriOct
I finally knuckled under and bought this baby (though I expect to turn it around and sell it, since it doesn't do anything I can't live without).  
The Guild TriOct is a fairly rare beast. I've never heard of this before and a google search yielded nothing. This one has the serial number 0115 so we're probably looking at something that was only a little more popular than the Beigel Sound Labs Envelope Controlled Filter. My sense is that we are looking at the progenitor of the Electro-Harmonix Micro-Synth for guitar, and maybe even the 360 Systems Slave Driver, although I think there were possibly two or three evolutionary steps between the TRiOct and these other units.  
Basically, the TriOct is an octave-down/octave-up generator. These two signals are mixed in with the straight signal with slider pots for each signal type, hence Tri (three signal types) Oct (octave signals). This is why I draw the link between the TriOct and Micro-Synth, which also has the ability to mix in straight and octave signals.  
A footpedal allows you to remotely select each signal type, in any combination you want, and a rear panel bypass switch gets you a straight feedthrough.  
The TriOct uses a combination of normal guitar signal and a special design hexaphonic pickup. The hex pickup is about the size of a very flat P-90, and is intended to sit on top of the body. It is low profile but tall enough that there may be a limited number of instruments it could be used on. I've got it mounted on an early 60's Epi Coronet, with the action raised a little higher than I like, and snuggled up against the bridge pickup.  
The pickup is encased in epoxy, which makes it a little hard to line up under the strings, since there is no real indicator of where the sensing elements are (i.e., no visible pole pieces). Basically, you have to try and line it up so there is just as much hanging off one E-string as the other. Four screw holes allow you to fix it to the body. Being a loyal member of Possum Lodge, mine is currently affixed with duct tape. The alignment thing doesn't really seem to be an issue, though. There are six trimpot accessible through the rear panel for adjusting relative level (i.e., sensitivity). Although the unit has a hexaphonic pickup, it is decidedly a mono unit, with a mono output jack.  
Popping off the lid one sees an entirely transistor-based architecture, on a nicely-tinned double-sided PC-board. The component side serves as ground plane and heat sink for what I assume is either a voltage regulator or a TO-3 style transistor involved in voltage regulation. It would appear that the supply puts out 30v DC.  
The board houses what look to be 6 identical circuits lined up side by side and a seventh, which I assume is for straight signal. Each string circuit uses eight 2N5133's, a 2N388, and a 2N404 (yup, two Ge trannies!), along with six 1N270 Ge diodes, a trimpot (noted above) and a wad of big clunky ceramic caps.  
So how does it sound? Not too bad, actually. For something that has a hex pickup, I was surprised to find you cannot play chords. Strumming two notes gets you something that can't seem to make up its mind.  
Although I've only listened to it through an 8" speaker, the octave below is pretty decent, with pretty flawless tracking from the lowest note right up to the 23rd fret of high E. Like all analog octave dividers, there is a perceptible delay between the original and octave when playing the lower strings. The tone of the octave is meaty, without being buzzy, and never overwhelms the straight signal if both are set fro approximately equal levels.  
The octave-up is underwhelming. It's *there*, but it ain't no Octavia. Still, it's rather warm-sounding, rather than harsh and, like the octave down, is predictable and tracks well. You get the octave up on every string for every fret, and engaing it with the footpedal gets you a very different sound. I didn't diddle with it enough yet to be able to tell you whether the octave up would track chords. Given how thin sounding my guitar normally is (and it ain't the pickups folks), I would attribute the stability of tracking to the use of a hex pickup. Exactly HOW this has such an effect is something I'd like to explore further. My guess is that the circuit for a single strong could function on its own. I'll see if I can trace out the schematic for a single string circuit before I sell this thing.  
Lest all give up, there still ARE pawnshop prizes out there.  
More later.  
2/1/2001 2:41 AM

wow, that sounds interesting! what year is that from???  
Were there any stand alone effects that provided an octave down, or an octave down with fuzz that might have existed in 1970? Might this have been that box?  
Too bad about the pickup, I wonder if it could be modified to work liek the rest of our stompboxes. Proprietary equipment, IMHO is a drag.  
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2/1/2001 3:52 AM
Mark Hammer
First octave dividers
I have no idea exactly what year it's from, but it has the stench of 1972-73 on it, in terms of packaging style, component count, and features. We're looking at a box with 67 transistors, which is a somewhat unheard of parts count for a guitar effects box prior to that period. That's only a guess, however. I stand to be corrected, as always.  
As to its status as a *first* octave divider, I somewhat doubt that. I know that the Conn company produced the Conn Multi-Vider, which the horn players in the Mothers of Invention played from about 1967 onward. For example, it can be heard in abundance on "Absolutely Free". The Multi-Vider was a mono device, oriented towards sax players, and used a clip-on mic, with a belt pack. I haven't seen any pictures of it in a long time, but the belt pack sort of looked like a Mutron III, with a cluster of rocker switches and a couple of pots. Its function was to turn an alto into a baritone, or make it seem like a baritone was tracking an alto (or a tenor tracking a soprano). I don't know if the Multi-Vider was the *first* octave-down device on the market, but it was certainly earlier than this Guild unit, and the EH Octave Multiplexer. My guess is that Maestro also had something out prior to 1969. The Rhythm 'n Sound schematic in my Jack Darr book has octave dividing capability.  
Guild and Electro-Harmonix share some common history from what I understand. From what I've read on the EH-Man's site, the Big Muff Pi started out as the Guild "Foxey Lady". Tran-o-philes may note that early EH units (such as the LPB-1, Muff Fuzz, and BMP) were replete with 2N5133's, the most prominent transistor on this Guild unit. Although the circuitry is completely different, a small part of me wonders if somebody who worked on the TriOct also worked on developing the Micro-Synth. It's easy to imagine a meeting or coffee break where someone piped up with "We had this thing over at Guild, where we could mix straight, octave-up and octave-down, and it was kinda cool. Never sold, but cool nonetheless. It would be neat to harness that to a sweepable filter." I'd be really curious to know if this is anywhere within driving distance of the actual course of events. EH-Man, Mike Matthews, Art Thompson, Steve Giles, you out there?  
Since the pickup simply provides six parallel signals, and the chassis provides the same detector/divider circuit in triplicate, it should be possible to have a single channel version of the unit, allowing one to scrap the pickup. At first, I was curious as to whether the cap values in each of the 6 channels were tailored to suit the anticipated fundamental frequency range of each string, so as to reduce false triggering, but I haven't seen any component value differences yet. There may well *be* some, but the parts are clustered close together, and I've only had it for 4 hours at this point.  
Speaking of EH, your question led me to dig up some back issues of Downbeat magazine that I held onto from the late 60's, in search of ads for the Multi-Vider. Although I didn't find any such pictures, I did find an ad in a June, 1969 issue for the EH LPB-1. The going price? $14.95.  
Also strange to see a full-page Fender ad touting them as "Foremost in solid state amps." The Twin, Vibrolux, Super, and Pro models shown in the ad are kind of like the deformed, mentally handicapped children that got wisked away to an institution before anyone in the neighbourhood got a look at them. If I covered up the name Fender, and showed these pictures to folks here or on Ampage, my guess is that *maybe* 5% could conceivably identify them as Fender (and I'd be among the other 95%).
2/1/2001 4:56 AM

I had always thought that the meastro rythm and sound was the unit the reed mothers were using, all the TV appearances show that unit.  
If anyone is interested I can probably provide a trace of the conn multivider in a few weeks.  
2/1/2001 2:54 PM
"From what I've read on the EH-Man's site, the Big Muff Pi started out as the Guild "Foxey Lady". "
The Guild "Foxey Lady" is *exactly* the same as the BMP. I traced one out. Only differences are a few minor component values, something EH was cavalier about anyway.
2/1/2001 4:14 PM
Joe Gagan
Thanks, Mark
That is a great story Mark . Very unusual stuff.  
Does anybody remember any details about the ungodly expensive hex setup that David Gilmour had built for him in the 70s? I think I read that he later sold it to Zappa [don't quote me, I still was a stoner back then].
2/1/2001 8:37 PM
2 Versions of the foxey lady!
A quick correction. There are 2 versions of the "Foxey Lady" I have a a 2 transister model, similar to the EH Axis fuzz I believe.  
I have also seen Foxey Ladies that are exactly like the second generation muffs.
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