My Tycobrahe Octavia is misbiased or not (it sounds gated)?

Started by gigimarga, October 30, 2008, 04:23:20 PM

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gigimarga

Hello,

I built a Tycobrahe Octavia using the Tonepad's layout: http://www.tonepad.com/getFile.asp?id=116.
I used an 42TM018 transformer instead of the recommended 42TM022, a BC560 for Q1 and two BC549C for Q2/Q3.
It sounded too nasty with the intesity at maximum, far away from the soundclips founded here: http://www.home-wrecker.com/salvo.html#octavia.

I decided to change it to positive ground, as i found here: http://www.geofex.com/FX_images/tyoct.gif.
I used an BC549C having hFE=650 for Q1 and two 2N3906 with hFE around 210 for Q2/Q3 (as Mark Hammer said he used in a post), i'd changed the intensity's pot cap to 22uF from 100uF and the Q3's emitter cap to 220uF instead of 100uF.
After all, i got the same problems: i can used it only with the intensity pot almost to minimum (and i have a Squier with low-level single coils!)
and the sound is very gated (i heard a lot of samples of it and it sounds amazing...mine sounds like a fuzzy-beast)!

I compared my voltages with the GGG's tested voltages and i found a major problem at Q1's collector and a minor one at Q3's collector:

Battery: 9.8V (mine)/8.8V (GGG)

Q1: C=3.13/5.10     B=3.80/4.50     E=4.46/2.30
Q2: C=9.80/8.80     B=3.13/2.40     E=2.52/1.80
Q3: C=5.23/5.70     B=2.52/1.80     E=1.82/1.10

After looking at the GGG's original schematic (http://www.generalguitargadgets.com/pdf/ggg_toct_sc.pdf) i saw that Q1 is reversed as in the GEOFEX's schematic!!!
And, after all, i found that i have almost the same voltages as here: http://www.home-wrecker.com/fuzz.html!!

So, my mind is blown now: how is the right positioning for Q1 and which are the correct voltages?? The transistors have wrong hFE? The transformer influences the biasing (stupid question i think...it's after the transistors...)?

Thx a lot all!