On Tuesday 02 April 2013 12:46:07 Ralf Mardorf did opine: > On Tue, 2013-04-02 at 11:32 -0400, Gene Heskett wrote: > > So I used a cmos op-amp which uses very little current at normal > > signal levels. The TLO74/84 family. These were great, and could > > make 29 volts P- P on a +-15 volt supply rail at around .007% > > distortion. > > I still own a lot of TL07* (at least a stick with some 702), it's > written that my Behringer mixer does use 4580 and it's written that the > ADA8000 does use TL072, but that the ADA8200 will use 4580. > > Years ago, when I got my Behringer mixer I worried about the many TL07* > I bought a short time, before I bought the mixer. A friend confirmed > that at that time TLs were less used anymore for audio gear. > > I never made ABX tests for op-amps, but IMO a lot of IC gear is able to > keep up with good discrete circuits, at least in the homestudio price > range those newer op-amps IMO do sound very good. And I wasn't saying that it was todays cat's meow. I forgot to mention that this was 25 years ago. Should have. The production video switcher we used for many years, a Grass Valley Group 300-3A/B, used a grocery sack full of a slightly bigger than an airmail stamp, custom made op-amp that Grass designed. Of course, as the far end of the bathtub curve of time vs failure rates approached, it lost a channel, one of those little ceramic cards had died. I called Grass, they wanted $1500 and would not guarantee that the remaining ones on the shelf were good. That wasn't good enough for me, so I started scouring catalog's & calling the chip makers. I forget who came to my rescue with a one rail 5 volt video speed op-amp with an in my hand price of less that 2$. So I asked for samples & they sent 5, gratis. I should have bought 50 because it was so much better and faster that it threw the color phase noticeably off when that mixer channel was in use. If I had sufficient stock, I would have shotgunned the other 5 identical boards so they would have all matched again. But changing them out was a good 3 hours a board, so it never got done, but by the time I retired, the other 4 were in it because of more failures. Since one board then had 3 of those in it, the color hue shift was getting to be obnoxiously obvious. When I announced I was retiring, the first thing they did was replace it because they knew I was the only one still living who might be able to fix it. They paid about 100k for another brand new one from a new company, and 4 years later it was on its last legs. Then digital needed to be done, so the building was rebuilt for a brand new rack room and two control rooms, 3 more edit bays, 2 production offices, and an all new area for engineering since there are now 2 tv channels, 4 programs, originating there plus a radio station. That has had its share of 'teething' pains, but the junk seems to have largely been swept out in the 5 years since, so its usually running pretty good. All with gigabit ethernet, and some 10Gb in one instance, its nice to be able to move a 1 hour long program file from one box to another in 2 or 3 seconds. :) Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> Its name is Public Opinion. It is held in reverence. It settles everything. Some think it is the voice of God. -- Mark Twain A pen in the hand of this president is far more dangerous than a gun in the hands of 200 million law-abiding citizens. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
