simonsez
Well-known member
Hi all,
I would love to hear your opinion and advice about a situation , here's the short story :
About a year ago, someone want me to build an insert switcher for him, 8 balanced stereo insert, 2 ch with m/s, 1 ch with blend knob.
The unit done, and works good and clean. Actually this is not the first unit I build, I've build few for other studio before and after this one.
The unit full of Burr Brown chip, INA137 balanced receiver, DRV134 balanced line driver, OPA2134.
After a month later he put in on his small studio setup, he said that there's weird noise when the M/S engaged, the m/s channel was connected to the diy igor sontec eq he bought, unfortunately he cannot do test procedure to see which one cause the problem, the m/s circuit or the outboard (by jumper the encoder output to decoder input) .
I told the owner to ship back the unit to investigate as unit warranty, but unfortunately he refused and prefer his studio tech guy to look at it.
His tech guy said that it is the power supply capacitor fault that make the DRV134 (m/s output balanced driver) make the noise.
His diagnostic was really surprising and technically non sense to me, because I use DRV134 chip in every circuit in this unit (monitor level circuit, blend circuit, output att. buffer). My logical thought was , if it's the PSU issue, then the noise would be everywhere, and always there, because they share the same PSU. I really doubt his diagnosis on this.
Does that make sense to you?
Best,
Simon
I would love to hear your opinion and advice about a situation , here's the short story :
About a year ago, someone want me to build an insert switcher for him, 8 balanced stereo insert, 2 ch with m/s, 1 ch with blend knob.
The unit done, and works good and clean. Actually this is not the first unit I build, I've build few for other studio before and after this one.
The unit full of Burr Brown chip, INA137 balanced receiver, DRV134 balanced line driver, OPA2134.
After a month later he put in on his small studio setup, he said that there's weird noise when the M/S engaged, the m/s channel was connected to the diy igor sontec eq he bought, unfortunately he cannot do test procedure to see which one cause the problem, the m/s circuit or the outboard (by jumper the encoder output to decoder input) .
I told the owner to ship back the unit to investigate as unit warranty, but unfortunately he refused and prefer his studio tech guy to look at it.
His tech guy said that it is the power supply capacitor fault that make the DRV134 (m/s output balanced driver) make the noise.
His diagnostic was really surprising and technically non sense to me, because I use DRV134 chip in every circuit in this unit (monitor level circuit, blend circuit, output att. buffer). My logical thought was , if it's the PSU issue, then the noise would be everywhere, and always there, because they share the same PSU. I really doubt his diagnosis on this.
Does that make sense to you?
Best,
Simon