Keeley 4Knob Compressor Troubleshooting

[GiovannyS10]

Hello guys,
I have been absent last month, but now i am backing to diy again. 
I am having troubles when try to build a Keeley 4-knob compressor. It sounds very good, as expected. But it has receiving a lot of interference. Specially mobile phone interference and sometimes RF interference - specially when i short the clip pot terminals using my finger. I re-did my build, this time adding some devices for prevent RF. Things that i already tried:

• Add a power filter circuit. A low pass circuit using a 47r series resistor + 100uF + 100nF capacitors to filter the input power and prevent specially 'hum' sound. I added a schottky too to reverse power protection.
• The footswitch is wired as ever, the circuit input is grounded when the effect is disabled. And the LED uses a voltage divider + capacitor to prevents pop sounds - it works great.
• Added a Pulldown resistor out from the circuit. A 1M pull down was added in the circuit output, directly wired on the out jack.
• I reduced the C13 for 47pF and added a 100r resistor in series with the audio input.
• Shielded all potentiometer and power wires using conductive sheet around the wires.
• All GND points are tested and working. The chassis is grounded too.
• Replaced the T1 for a 2n5088 - and by the way the sound is better now, more strong... But the interference stays.
• I tried a 47pF between the T1 Collector and Base, but not worked, so i removed it.

I am almost sure the problem is around this first transistor, but nothing i did worked completely. If there is a mobile phone at least 2m of distance, the interference is crazy horrible. I already built two of them, and both with the same problems. The first i did not add all that modifications that i quote before. I only did it in the second one, but nothing happened to prevent the interference.

I used this schematic:

And this layout:
http://4.bp.blogspot.com/-A1r09ZWm944/V30UoEtIyJI/AAAAAAAAD3k/qhWcz2wbZ90DjrPAGDaV_TFwlv7gb1-GQCK4B/s1600/Keeley%2B4-Knob%2BComp.png

I did not audio probe yet. Maybe this schematic are wrong?
P.S: I could notice in another posts, searching on Google, that some guys used tantalum instead eletrolytics. Maybe its the trick? I can't see how it can help to prevent RF...

[PRR]

Is it in a metal box?

A cellphone at 2M is a very strong source.

[GiovannyS10]

Is it in a metal box?

A cellphone at 2M is a very strong source.

Yes my friend. It's in a shielded metal box. And even with all this things that I did, it continues with a lot of interference. Works okay, but with interference.

[GiovannyS10]

Hey guys, here is the audio probe result:
I got phone interference in almost all circuit, even in its input. But in the most time this interference is low and intermittent, except in that pink marked areas. In this areas, the interference is deafening.


In the schematic you can see these components like:
Capacitors: C5, C8 and C6;
Resistors: R9, R11, R12, R14 and R16
Transistors: T2, T3 and T4
Diodes: D2 and D1

The interference in T4 (Q4 in layout) is a bit minor than in the other marked points.
I noticed that in schematic D1 and D2 are 1n914 and in layout is 4148. I am using 4148. But i do not think its causing any trouble.
I will investigate more to find the problem.
And as you can see, i forgot to mark the audio out (around 10K resistor (R16)), just consider it marked.
I will change that 4M7 resistor in Input for a 1M too.
Would be nice if you guys could help Thx