One transistor Octave Up?

[Jaicen_solo]

Ok, if I want to graft an octave effect onto a fuzz that I have. I want it to be super simple, so ideally just one transistor, a couple of diodes, something like that.
For example, how much of the green ringer can I cut away if I drive it directly from the collector of Q2 in a fuzz face?

[rousejeremy]

http://www.diystompboxes.com/smfforum/index.php?topic=71134.40 There's a vero on page 3 that works pretty well.
It's better with an LPB at the end http://www.youtube.com/watch?v=YzbgwMNvyhk

[Jazznoise]

You can do a one transistor octave with no volume loss, just follow a Common Emitter with a diode bridge.

.. but you'll need an op amp after the diodes for recovery gain!

[Derringer]

http://www.diystompboxes.com/smfforum/index.php?topic=86740.0

if you have enough gain available, this might do it .. otherwise you'll need a boost stage

[brett]

Hi
1 transistor octave?
Hmm... I'm no expert, but I think there's only 1 transistor doing the octave in the Octavia (Roger Mayer's).  The first stage is a booster/fuzz.

I can't remember the details of RM's circuit, but you might try it like this:-
1. Make a single transistor booster (common emitter or common source e.g. Stratoblaster)
2. Half-wave rectify the signals from the collector/drain and emitter/source with a series diode each.  It's a booster/phase splitter.
3. Connect the half-waves back together via a resistor/s to ground (100k to 220k).
4.  "tap" the output from "above" the resistor via a small cap (0.1uF)

I think that'll work.

[Ben N]

Can you do phase split with gain?

[mac]

The Green Ringer 1st stage is direct coupled to the transistor that does the octave up. So if you bias a FF at 4.5v you can direct couple the Green Ringer 2nd stage, and depending on the final volume the 3rd one.
If the FF hits the octave up transistor too hard you can put a resistor between stages to reduce the signal.

mac

[Jaicen_solo]

Thanks guys, i'll have a look at perfing up the GR stage, and see how that works.

[brett]

HI
RE: Can you do phase split with gain?

Oh yeah, the gain can't be too much or the octave effect gets lost.  However, gain of 3x is enough to mininise losses and keep the octave effect.
cheers