Pharoh fuzz with different transistors

[JebemMajke]

I'm about to start building this nice fuzz and i was wondering if I am to replace q2,q3 and q4 with Bc 550c's ( originals seams to be 2n5089's ) should I use trimpots in order to bias transistors correctly or just leave 10k resistors?
schematic

[Gus]

With BMP the transistors are not that important for the sound.

The tone section, high pass sections, low pass sections, gain setting parts and clipping diodes have more to do with the sound that the Si transistors used.

[JebemMajke]

Ok, but I m pretty sure that miss biased muff hums like crazy. That's my concern here, the noise issue.

[Gus]

A BMP won't misbias because of the design.  The BMP is less sensitive to transistors used.  The BMP uses good bias DESIGN.  Noise will be from some other issue.

[JebemMajke]

Ok
Second question
Is this the way to wire second switch? on/off/on spdt

[LucifersTrip]

transistors will make a difference if hfe < 100

after you get to around 150+, the collector voltages change slowly as the hfe increases

[LucifersTrip]

Ok, but I m pretty sure that miss biased muff hums like crazy. That's my concern here, the noise issue.

what voltages do you have on the transistors?

Second question
Is this the way to wire second switch? on/off/on spdt

yes

[JebemMajke]

1-5.6, 2-4, 3-8.6

I'm currently in process of debugging. I've found that fuzz pot is not working properly so after I replace it i'll measure voltages again.

[JebemMajke]

q1 C 5.54,B 0.55, E 0.31
q2 C 4. 08, B 0.63, E 0.04
q3 C 8.88 B 0 , E 0
Also when I took the output from the exit of the second stage there was no distortion what so ever, and I do remember that first two stages of BMP have some distortion. But now it works like clean boost, but with no boost :/, volume is the same level as bypass.
I think that caps are bad, this is the first time I've used these no name caps. The price is the same as wima's but wima's caps my supplier had were 7mm and these weere 5 mm. So i went for smaller caps.

[LucifersTrip]

q1 C 5.54,B 0.55, E 0.31
q3 C 8.88 B 0 , E 0

Q1C is a little high, but what's happening at Q3?  C's on all four are usually in the 4-5V range. B is also shorted to E and neither should be 0.
Q4?

Please post the schematic if you have one.

[JebemMajke]

I've thought that I already have, strange. Here

[LucifersTrip]

thanx...1st resolve the issue of Q3 B & E = 0 (grounded)

should be similar to Q2

[JebemMajke]

Second 6.2 k was touching q3's E. I've just cleaned that mess. Ill try it and measure it again.

[JebemMajke]

q1 C 5.54,B 0.55, E 0.31
q2 C 4. 08, B 0.63, E 0.04
q3 C 3.98 b 0.62 e 0.04

D1 + 3.76 - 3.76
D2 + 3.76 - 3.76

No sound at all

[LucifersTrip]

Q4?

if Q4C is 3.76 and Q4 B,E are reasonable you should be getting sound...so, next step would be to look into offboard wiring

[JebemMajke]

Those 0.47 caps ... they were the problem. I've took them out and replaced them with green polyester caps. Now it kicks ass.

[JebemMajke]

Now I've made another one. And some issues are apparent ... again ... I feel like a such a noob when it comes to this circuit ...

q1 c 5.46, b 0.90, c 0.32
q2 c 4.19 b 0.64 e 0.04
q3 c 3.94, b 0.64, e 0.04
q4 c 4.89, b 1.44, e 0.87

Sound is like it's a low gain overdrive ... changes in sound are apparent when i use tone, high, low/high switch and ge/none/si switch. But still there is no gain ...

[JebemMajke]

It's the tone pot. I;ve changed the pot, changed wires, re wired it 3 times, still it;s disrupting the signal. I get full signal only when those wires are pushed by my finger ... wtf?