Guild TRIOCT (whhhaaaaaaat??)

Started by digi2t, July 16, 2013, 12:02:03 AM

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digi2t

QuoteQ3 looks wrong, look at the PRR post, the E and C look like they should be flipped.

Damn, I made a note of it, but neglected to flip it in TinyCAD. It's corrected now.

QuoteAt the time of this post you have the input and output caps at the output amp section BOTH going to the input (base) of the transistor stage I would think the .2uf goes to the collector

Another oversight. Thank goodness that you guys are here. Corrected as well.

Here are the redraws;









I'm gonna go wipe the egg off my face now.  :icon_lol:
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Mark Hammer

Maybe I'm just used to it being drawn a certain way, but what part is doing the octave division?

digi2t

Quote from: Mark Hammer on September 14, 2013, 08:52:45 PM
Maybe I'm just used to it being drawn a certain way, but what part is doing the octave division?

"Probably", and "above my pay grade" is the best I can do for answers here.  :icon_lol:

Step right up folks, I'm all ears too,
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Mark Hammer

Figured it out by consulting a few octave dividers using discrete flip-flops.  Q6/7 and Q8/9 each make up a flip-flop.  Guess I was too used to seeing it drawn another way.

digi2t

OK, I decided to sit down and record some transistor voltages. I figured it would be "a good thing", since I'll probably never see another one in this life time. I started with the string amplification section, and immediately, I ran into an anomaly. I did just three sections, strings 1, 3, and 5, thinking I wouldn't see much difference. After all, all six sections are identical component-wise. Where the skew is, is with the Ge transistors. Here's my sheet;



Q4 is the PNP, and Q5 is the NPN. As you can see, I was getting pretty big differences in voltages between the three section. On the right side of the page, I decided to record all the B and C voltages for Q4 and Q5, since Q4E, and Q5E are fairly even across the board.

So... what's going on here? Leaky devices? If so, does it matter, or are they simply switching here, so gain/leakage doesn't matter?
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liquids

#65
Quote from: digi2t on September 13, 2013, 12:34:49 PM
And finally, a new installment of "The Hen's Tooth Café", featuring this rare clucker. Enjoy.



Some thoughts...
The pickups is mounted pretty close to the bridge. For whatever reason, the hex pickups of today that work with synths mount right next to the bridge.  I wouldn't doubt a lot of filtering and such goes into that, though.  The benefit is the string moves around less when it is plucked...but fundamentals are stronger near the neck...

Since this is effectively a standard-style sub-octave and full-wave rectifying/analog clipping "octave up," best results are with the neck pickup, and at that, often with the tone control down (lots of LPFing, etc)...the closer you can get to the neck pickup the better, though I understand what you said in regard to 'bottoming out' on strings on the guitar because of the hex pickup's mounting.

You may get better tracking with the octave up with pickups that are closer to the neck...even if that is not effectively doable.  I have no clue how or what guitar they anticipating that thing being mounted to (some kind of jazzbox with a floating pickup maybe?!), but it's kind of a shot in the foot.

Followingly...chords may work better if you play a kind of "bar" chord on the 6th fret or higher.  Open strings rarely if ever track well on most basic devices like this.  The filtering doesn't seem to well designed either, so, it may simply be an uphill battle.

It's impressive what you've done here.  Do you plan on keeping it, modifying it, or tracing it and selling it (giving it back to whomever it belongs to)?  It's certainly a circuit worth learning from on some levels...but it just seems so far from ideal!  A neat piece of history, and conceptually, rather cool.
Breadboard it!