Digital controlled EQ started oscillating

Hi,

I recently bought a digital controlled analogue console, this week however 2 EQ's started oscillating (one actually stopped oscillating for the moment). The EQ is pretty minimal , with LF and LG controls, fully parametric mid , and HF/HG controls. It's is build arround 4560L and 4580L opamps and Dallas semiconductor DS1267-50/ DS1267-10 digital controlled potentio meters.

When inserting the EQ, I get a muffled hollow sound (and a ringing sound when oscillating). The frequency of the oscillating doesn't really change when I change EQ settings. Because both EQ's stopped working at the same time (channel 1 and 2), I'm guessing it has to be something they have in common. It is a known problem that the EQ's can start oscillating (due to the instant recall I guess?, clocks ...? ), but changing the EQ controls stops this (but unfortunatley not in my case).

I already contacted the tech who is familiar with these consoles (Tactile M4000). But perhaps some of you guys have a solution while waiting for his answer.

... 4560L and 4580L opamps

Click to expand...

?
so it's not a euphonix cs2000
oh !
it's a Tactile M4000

swap the EQ to another channel ... if possible
does the oscillation follow the EQ section or does it stay with the digital control circuit ?

gut feeling is that the oscillation is caused by the usual analog opamp issues