Rusty Box

[Zanius]

I wanted to do this since the first time I visited this place. I felt the time was right and went for it!
But there is a problem. First let me tell you how I've built it.

Rusty Box

First, I didn't use the power supply provided, I used this bipolar converter instead. Note that after reading the comments on the Rusty Box page, i found out that I needed to connect pin 1 and 8 of the Lt1054, otherwise there was a whine in the output.

When first tried it I thought it worked, and after boxing I found out there is a major distortion in the sound ONLY when the treble pot is on AND if the gain is over 12 o'clock. If it is all the way down, everything sounds fine. When I turn it a bit up, there are violent distorted sounds coming from it.... Let me clarify, the distortion comes with the playing. If I just strum lightly everthing is good.
 So I thing something is wrong with the treble part of my circuit. I swapped all Ic's and Trans one by one and nothing changed. I will start measuring now and post my voltages later on.

As I said I already boxed it so, no pictures of the soldered side of the board (and I really hope I won't need to take it out of the box  )

Here is one in the box though, note that the Ic of the converter is now changed from 7660 to lt1054



As I said, I'll start measuring, but since (I think) I know where the problem is located, someone could have an idea about what's going on.

Thanx guys!

[Zanius]

Voltages:

input unplugged 9.63
input plugged 9.2

Power Supply

LT1054
9.2
4.4
0
-4.4
-8.7
5
4.8
9.2

Rusty Box

Voltage inputs
+v 16.6
-v  -16

Tl071
-15.9
0
0
-16
-15.8
0
16.6
0

Q1 - Bf256B
D 0
S 0
G -14.5

Q2 - MPSA18
C 16.7
B -1.45
E -3.06

Q3
E -1
B -1.6
C -1

Q4
E 0.18
B -0.45
C -1

Q5
E 0.6
B 0.01
C -16.2

Q6
E 0.22
B 0.01
C -16.2

Q7
E 0.6
B 0.02
C -6.24

Q8
E 0.6
B 0.01
C -16

I hope someone can get something out of this.
The thing is, I haven't used a rusty box before, and all videos on youtube don't really cover many settings. I mean, it seems to work fine, but when you get a little above normal settings (with high gain, high input gain and boost switch) it starts to crack (again, only when treble pot is on). It is almost as it is supposed to work that way...

[Zanius]

So, I keep testing and now my whole interest is around q3.

If I just take it off, there is a serious volume boost and the distortion problem vanishes... with it a bit of the pedal's character vanishes too though.
Tried a bunch of other trannies, most of them just "gate" the output.


(from John k's site)
I've been testing resistances and connections around it following the schematic and everything seems to check out fine...

Gonna keep testing before I ultimately throw it out of the window
with the box that is.

[Zanius]

....and of course it was just a short over a hole in the board.

Funny how it was manifesting itself though. It was between the emitter of q2 and it was actually overriding the 4u7 filter cap....Thus the unwanted noise. Now let's close the enclosure and this topic and never speak of it again. Thanx to anyone that read this.

Going for a smoke

[Beaker]

I'm glad you got it sorted Zanius. It happens to all of us so don't worry.