opamp recomendations for this trident

pucho812 · Apr 17, 2013

o.k. so Because of a hectic tour schedule that the owner has been on, The work I was doing on a trident 80b got put on hold for a minute.

I am down to the aux master section being completely destroyed(burned traces that are gone due to burning off, dead resistors, dead eletrolytics and dead opamps, it needs a complete rebuild..

I am planning on the console being run as is, with the +/-20 volt rails. The owner does not wish to install a different PSU and to be honest the rest of the console is working so dropping down the voltage to something more common like +/-18 is unlikely to happen at this time.

Does anyone have any suggestions for the trident tl071 replacements that will work +/-20 volt rails? Swapping opamps is so much to consider like how much current they pull etc, I thought maybe some of you might suggest something?

mjrippe · Apr 17, 2013

Hmmmm, looks like +/-18 is the Max rating for TL07x. You could throw in 7815/7915 voltage regulators at the power input - they're good for one amp so that would run a lot of them.

I've worked on an 80B with hot-rod chips and I didn't think it was an improvement. It might have been cleaner, but the gain staging was odd and headroom actually decreased overall.

pucho812 · Apr 17, 2013

yes correct standard tl07X are +/- 18V or 36V total however trident had tl071's made that went to +/-20V or 40V total. so not trying to hot rod so much as make a functioning console. I am feeling that the PSU's do not have an adjustment so I can drop it down to +/-18 and not worry about it. I would rather swap out the psu's but as mentioned before they do not have funds at this time to to that. Just got a phone call from their engineer wanting to do a session on the board asking all about it. The sound of the light bulb going off when I said why don't you sub-mix in the box to do headphone cues, your only running a single 192 at the moment anyway.

So might have delayed this altogether, at least I am hoping.

Brian Roth · Apr 17, 2013

I can't find schemos for the PSU, but here is a snapshot of the innards of one. You can see RV2 for the positive rail and RV3 for the negative. I don't know how much adjustment range they have, but I suspect at worst you could swap a resistor or two in the pots' circuits to gain enough range to drop down below 18V.

http://brianroth.com/pix/aaron/trident80b-nov2010/IMG_0111.JPG

Bri

Edit: As for possible chip substitutes, you may be out of luck trying to hit all the parameters: single opamp, 8 pin DIP, low current consumption (under 2.5 mA) AND ability to handle rails greater than 18V.

Kingston · Apr 18, 2013

TI claims a "direct tl07X upgrade" for these:

http://www.ti.com/product/tle2071

Quiescent current is very similar (1.6mA vs. 1.4mA of tl071). tle207X has an absolute max rating for 19V rails so you may be able to work with this.

But tle207X also has about double the bandwidth and 3X slew rate of tl071 so take TI's "direct upgrade" recommendation with a grain of salt. Both are FET input.