Trident 80B TL071 replacements

[turbofoda]

Hi Folks,
I am just fixing some issues on my recently aquired Trident 80B board and I am looking for some parts,
especially:

replacements for the (beloved) TL071CP
all the new ones are +/- 15V, but the desk is running them on 18-20V !
can I replace them? will I just fry them over time? Were they selected ones to survive 20V?
I definitely LOVE the sound of the desk, so I will NOT go for BurrBrown replacements or similar !!!

replacement of the plastic clips holding the modules in place

I would love to have answers to these questions - I have another friend here in Austria working on a T80B, he'd be also glad for some help in this....

thank you all in advance,
George

[F_Moscowitz]

Regarding the TL071 you can buy today, maximum supply voltage is listed as +/- 18v:

http://focus.ti.com/lit/ds/symlink/tl071.pdf

I've sometimes found the data listed in the search columns on Mouser and Digikey to be inaccurate, I've had to double check more than once!

Check out the TLE series of chips from TI - the "direct replacement" upgrade from them - I've found they sound just slightly clearer, +/- 19v (that's not a typo), and same current consumption!

I'm no help about the clips I'm afraid.... I have a Neotek. Good luck!

Frank

[waltzingbear]

for the nylock "clips" go to my website where I have a link to a supplier and the right part number for both the Neve and Trident parts. You need to save the center pin and reuse it, it is difficult to source that part in the same form. Other forms are possible in small quantities from the same vendor, but less attractive and just plain different.

http://www.waltzingbear.com

drill down thru the schematics pages to Trident and you'll see it.

the original chips were sourced directly from TI or Philips (can't remember) and were not the generic TL0 part, but the same part in prototype and spec'd for +/- 20V, today I would turn down the rails to +/- 18V if you want to use TL0 parts, however I will say I have one client who uses the TI TL0 parts in their TSM and runs them at +/- 20V with no problem.

The part could be replaced with the newer National LME 49860 or 70 (dual/single) which has a +/- 22V rating and sounds terrific. That however is a choice of flavor.

Alan

[Jim Williams]

If you're willing to go up the food chain a bit there are some newer fet input opamps that are fantastic. First, no go at + - 20 volts, trim down those supplies as there is no benefit from + - 20 vs + - 18 volts, a 1/2 db difference.

There is the TI THS4601, a $15 part with low noise and a 100 v/us slew rate plus high output current. Then there is the BB OPA827. Now there is the new AD4627-1, a 60 v slew rate. Now out is the BB OPA1641 fet opamp with low noise, a superior OPA134 replacement.

If you go bipolar, there's the LME series from National, the BB OPA211 or 1610, and the AD8597 from Analog Devices.

[santiago]

we have the originals and the imput trasformer too

santiago

[Jim Williams]

Trident users are reporting that the ADA4627-1 is the clear winner here. Low noise, 60 v slew rate, precision outputs. Those let you remove nearly all of those electrolytic coupling caps permanently. The input bias current is in the pico amp range so you can connect fader wipers right to the opamp inputs without bias current "scratch". Pull those electrolytic caps out and you really can hear new stuff. Plus the low end is magnificent and full. The exception is the stereo summing amp pcb, a LME49710 or BB OPA1612 or the new LME49990 are better choices.

[brianroth]

Dear Jim,

Out of curiosity, I looked up the specs on the ADA4627-1, and indeed it looks interesting! However, according to the Analog website, the least expensive version I found runs $7.40 in quantities 100-499, and Digikey's pricing in "1 off" for the SOIC is $11.25/chip! Add on the cost for a Brown Dog SOIC -> DIP adapter, and the cost to retrofit an old Trident becomes breathtaking! <g>

Oh, yes, I assume each socket will require PSU bypass caps and other misc. stuff to keep it stable....

Best,

Bri

[Jim Williams]

Plus it's best to replace the cheap leaf sockets with machined sockets, add $.25 each for those too. Those fit the gold pinned Brown Dog adaptors tightly.

An 80B is still worth $25g's. The cost of these parts is not that high considering the value of the console and it's stable re-sale value, unlike less fashionable consoles that sell for 10 cents on the dollar used.

I didn't say it's cheap, but good. Good costs. I believe it's worth it. Try them on one channel and report back. They are excellent in the mic preamp card especially if you do the non-inverting mod to the first stage of that flawed design.

[Fleximan5]

Hi Jim
Did you get a chance to put these in a Fleximix input module and stereo summing module?
Similar recommendations with eliminating coupling caps and not using the 4627-1 in the stereo section?
Thanks and Best
F5

[Jim Williams]

Doug Sharrot in MI has done it on his modified Flexmix. He says it beats all the other high test opamps he's auditioned. I've used them in situations where bias current must be low, solo switching circuits is a great place for them.