TC 1140 EQ is Broken !! HELP

Hello,

I had my tech install 4x IC sockets on the Filter board of my TC 1140 HS parametric EQ so I could swap the stock OP amps.

I swapped 3 of the TL074 op amps to MCC3079P chips like some members here and at Gearslutz recommended
(the 2nd, 3rd and 4th) for better mids/highs and kept a stock TL074 for the lows.

While playing my electric guitar the day after the mod, and there was a loud popping sound and my output level/sound immediately crashed (went very quiet). Almost no sound was coming from my amp when the EQ section of the TC was engaged. When I bypassed the EQ section, it was fine and the guitar is loud again! Something  has blown / damaged in the EQ section of the 1140. The preamp section is fine.

Was it the Op amp mod that caused this ? What do you think has happened to my EQ ?!?!
It was fine until I installed the 33079 Op amps ...

How about asking your "Tech" who worked on it.
Broken is just a statement,
I take it it worked OK until the "Tech" touched it.
Swapping Op Amps is a usually wasted pastime IMHO, with exceptions !
Depends on  Circuit Topology

Looking at the current draw on the data sheets for both op-amps might give you a place to start looking.

What can you learn from this ?:

Rule #1: "Never touch a running system"

I have experience with the MCC33079 op amps before and moderator here Gyraf has recommended the upgrade on several threads before.

I tried installing the old TL074 op amps again and now the unit works fine again. Lesson learned!! Unless Gyraf can help me?! Haha

yes, it's a standard mod I've done several times (an never ran into problems?). I only replace the two upper band's opamps, the lower doesn't really do any real difference.

Maybe your PSU is weak?

Jakob E.

Ahh Ok, well I think one of the 33079 chips died, because I took them out now & swapped th for tl074 and everything is fine again...

I'll try just one or 2 fresh 33079s soon and see if that makes a difference....