Gelf Electronic-any info

[Jim Zuehsow]

[quote="rotation

I read i could transform Gelf console into high end console with lots of headroom by changing 130 tantals to 130 Panasonic 47uF (35 V) and replacing 4 unknown (to me) caps from, i guess, PSU to 4 RIFA 1000uF (25 V)...

Just because the cap is a tantalum doesn't mean it should be replaced. There have been cases where someone replaced all those nasty tantalum caps in a Neve module, and totally destroyed the "character" of the sound. It's usually better to modify one channel and then compare it to a non-modified channel to see if there was in fact an improvement. It's easy to fool oneself if you believe all the hype and BS that goes around. Meaningful measurements are important too, and don't forget to also listen to actual program material through a high definition monitoring system, so you can hear if things have gotten better or not. Also, I generally use capacitors quite a bit larger than 47 uF, usually in the 100 to 220uF range, and depending on the circuit, either use polar back to back with biasing, or non-polar for coupling. I do not, under any circumstances use pure silver foil caps insulated with extra virgin olive oil, handmade by monks in a Tibetan monistary, but sometimes I do use a tantalum for it's particular quality.

 

[da_ardvark]

I do not, under any circumstances use pure silver foil caps insulated with extra virgin olive oil, handmade by monks in a Tibetan monistary

Hey don't knock 'em till you try em :grin: [/quote]

 

[rotation]

I finally got some good pictures of input module. There are two bipolar 22u/35v capacitors, one seems to be tantal (i'm guessing, someone else said so), TL074, MCI 458P (IC), few resistors and some inductors.

Signal from XLR goes to mic/line switch and then to transformer's primary, secondary is connected to TL074 with 22u/35V capacitor (there are some inductors, resistors between).
After TL074 and some resistors and inductors comes MCI 458.
After MCI and some components are two ouputs, one shows +-E, the other 1234.
Of course there are pots, routing switches and other stuff.

I tried to do my best to give a bit of explanation. I got good photos and i'm trying to post them here.

PSU is in a separated box (not 19 rack), full of dust, burned on some places (or very overheated). I will open it, measure Volts and Amperes and change what has to be changed.