EMS Filter with no output

Omega · Joined: Oct 11, 2010 Posts: 16 Location: Böblingen

Hi,

I have a problem with the EMS Filter. I get nothing out from the output. What I tested so far is: checking the voltages (+/- 15V, +/-12V, -9V). All these were o.k. I made in a
next step the check against GND. Everywhere I expect to have GND contact I find the contact.
Then I put a signal into the input jack. What I can measure at Pin 14 of TL074 is the nice signal (that's what I expected). I see also the signal (with a reduced voltage) at
Pin 2. But then no signal is detected anymore.

I measured all pins of the CA3046. Maybe someone can have a look at. I will post here my measurements. All voltages are DC voltages (except Pin2).

Pin 1 ==> + 5.0 V
Pin 2 ==> (Signal)
Pin 3 ==> + 2.8 V
Pin 4 ==> + 3.5 V
Pin 5 ==> + 3.0 V
Pin 6 ==> + 8.0 V
Pin 7 ==> + 8.0 V
Pin 8 ==> +12.0 V
Pin 9 ==> from +0.1V to - 4,5V depending on the frequency poti
Pin 10 ==> - 0.8 V
Pin 11 ==> +12.0 V
Pin 12 ==> GND
Pin 13 ==> - 0.8 V
Pin 14 ==> + 2.8 V

Maybe everything is o.k. with these measurements and I can look forward to the next piece. But unfortunately I am not so experienced so I need help on this.
I'm so sorry....

Embarassed

kkissinger · Posted: Mon May 02, 2011 4:38 am Post subject:

I had a similar symptom (no output) when I built my Yusynth EMS filter. You may want to scrutinize every solder joint on the diodes -- all it takes is one cold joint to mess up the works.

I've built a lot of Yves' circuits and the solution to every problem was to find a cold solder joint or a solder bridge and correct it.

An oscilloscope is useful for signal tracing --- you may be able to isolate the area where a bad solder joint exists.

Good luck with your troubleshooting -- once you get it working, you will enjoy this wonderful filter!