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Trident Series 65 / 24 Mic pre mods
Old 6th June 2017
  #1
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jctaudiodesigns's Avatar
Trident Series 65 / 24 Mic pre mods

So I would like to see what people have tried and liked as far as mic pre amp mods on this console. I have changed the op-amps to the LME49710 and that has helped, but I still want a little more fidelity and warmth. Thinking about changing the caps feeding the preamps, but what has worked for you guys?
Old 6th June 2017
  #2
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voodoo4u's Avatar
How's your power supply? If original, I would start there first. The Trident 65 power supplies were notoriously underbuilt. It's been years since I sold mine, but I also started with the BurrBrown Op-amps and it made a difference. Did you get the ones in the the submix section as well? Maybe PM Jim Williams. He could probably steer you in the right direction.
Old 7th June 2017
  #3
I seem to recall the ground bus was weak as well, some folks installed a much more robust ground bar across the back. As voodoo said the PS was weak at best.
Old 7th June 2017
  #4
Trident Mods

I owned a Trident 24 with Series 65 Input channels and Series 75 Busses.
I like to mod gear to make it better. In other words, I did what you seem to be going for. I will tell you, I wouldn't blow a lot of money trying to get much more out of the Trident 24/65/75 type boards. They are nice boards and I made some great records with mine. But, in reality and I know this is hard to hear, The Tridents in this series to me do not sound as good as say a Soundcraft Ghost. On the Trident, I spent the cash replacing all of the IC's with upgraded low noise etc. Same with the capacitors. In the End, a Stock Soudcraft ghost sounded about the same if not warmer and bigger sounding. I am not saying the Tridents don't sound good, but it is what it is and it will never sound like a Trident 80 series board.
Old 8th June 2017
  #5
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voodoo4u's Avatar
Quote:
Originally Posted by Argali View Post
I owned a Trident 24 with Series 65 Input channels and Series 75 Busses.
I like to mod gear to make it better. In other words, I did what you seem to be going for. I will tell you, I wouldn't blow a lot of money trying to get much more out of the Trident 24/65/75 type boards. They are nice boards and I made some great records with mine. But, in reality and I know this is hard to hear, The Tridents in this series to me do not sound as good as say a Soundcraft Ghost. On the Trident, I spent the cash replacing all of the IC's with upgraded low noise etc. Same with the capacitors. In the End, a Stock Soudcraft ghost sounded about the same if not warmer and bigger sounding. I am not saying the Tridents don't sound good, but it is what it is and it will never sound like a Trident 80 series board.
I didn't want to be impolite, but Agali is right. I originally had a Trident series 70, sold it and thought, years later, I would get another Trident. I ended up picking up a series 65 thinking, hey, it's only 5 numbers, it can't be much different. I was wrong the difference is huge. I was so disappointed. So disappointed that I replaced it as soon as I could afford to. Before you spend too much, consider saving your cash and looking at a series 70 or Trimix. They're both almost the same and they're much closer to the great, warm series 80 sound that Tridents are known for.
Old 8th June 2017
  #6
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jctaudiodesigns's Avatar
Quote:
Originally Posted by voodoo4u View Post
How's your power supply? If original, I would start there first. The Trident 65 power supplies were notoriously underbuilt. It's been years since I sold mine, but I also started with the BurrBrown Op-amps and it made a difference. Did you get the ones in the the submix section as well? Maybe PM Jim Williams. He could probably steer you in the right direction.
Power supply has been upgraded for sure! And I did the upgrade on the opamps though out the console.
Old 9th June 2017
  #7
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brianellefson's Avatar
Wish I would've saved copies of the schematics. I owned a Trident Series 24 that had originally been modified by Warner Chappell in Nashville. They had a guy put toggles on every channel for high and low EQ shelves. That thing was pretty killer.

If I recall correctly, the master had an all new circuit that was housed in a box underneath the console. There was also a toggle for main and aux monitors. Two power supplies. One just for the +/- power rails. Copper ground bar added. Toggle to bypass the line amps on each channel. Toggle to cut the send/return loops from each channel. Toggle added to each channel for phantom power (they were on back of the console).

I think the biggest difference came from having an upgraded master. It was basically bypassing most of the electronics on the circuit board of that channel and using a new stereo amp that was in the box mounted to underside of console. During my time with it, it just sounded amazing. I really liked using it.

I imagine you could find someone to modify the master bus and design a new stereo amp for it. Looking in that box below the console, it wasn't anything too crazy.
Old 9th June 2017
  #8
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I could have purchased something really nice with the money I put into my 65 years back. Which I eventually did after the fact.
Old 12th June 2017
  #9
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jctaudiodesigns's Avatar
Quote:
Originally Posted by David W. Jones View Post
I could have purchased something really nice with the money I put into my 65 years back. Which I eventually did after the fact.
Well I got this console at a really great price, and it's so easy to work on, so I am keeping it for a while.
Old 12th June 2017
  #10
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jctaudiodesigns's Avatar
Quote:
Originally Posted by voodoo4u View Post
I didn't want to be impolite, but Agali is right. I originally had a Trident series 70, sold it and thought, years later, I would get another Trident. I ended up picking up a series 65 thinking, hey, it's only 5 numbers, it can't be much different. I was wrong the difference is huge. I was so disappointed. So disappointed that I replaced it as soon as I could afford to. Before you spend too much, consider saving your cash and looking at a series 70 or Trimix. They're both almost the same and they're much closer to the great, warm series 80 sound that Tridents are known for.
You are not being impolite. I bought the console at a GREAT price and I have done several things to the console and it already sounds better. I just want to know what people have done that sounds good.
Old 14th June 2017
  #11
The 65 mic pre design is a standard 1970's style instrumentation amp, two transistors in front of an opamp without global feedback applied.

Those are also found in early Soundcraft designs. They are rather dirty at higher gains. A better opamp won't do much to fix that.

They can be fixed up at the expense of stripping off all the old parts and rebuilding it into a trans-amp with global feedback. Then all those issues go away. Use low noise transistors and you get -129.5 db EIN specs.

The master mix section is also weak. High value resistors in the balanced output stage will add noise if a bipolar opamp is used. Here all those resistors are removed and re-scaled downward to lower the resistor noise contribution.

I use a fast super low noise Analog Devices opamp for the stereo sum stage in place of the 1976 vintage NE5534. It also has 20 more db of loop gain at 10k hz so then the mix is cleaned up substantially when a large number of inputs are sumed.
Old 15th June 2017
  #12
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brianellefson's Avatar
Quote:
Originally Posted by Jim Williams View Post
The 65 mic pre design is a standard 1970's style instrumentation amp, two transistors in front of an opamp without global feedback applied.

Those are also found in early Soundcraft designs. They are rather dirty at higher gains. A better opamp won't do much to fix that.

They can be fixed up at the expense of stripping off all the old parts and rebuilding it into a trans-amp with global feedback. Then all those issues go away. Use low noise transistors and you get -129.5 db EIN specs.

The master mix section is also weak. High value resistors in the balanced output stage will add noise if a bipolar opamp is used. Here all those resistors are removed and re-scaled downward to lower the resistor noise contribution.

I use a fast super low noise Analog Devices opamp for the stereo sum stage in place of the 1976 vintage NE5534. It also has 20 more db of loop gain at 10k hz so then the mix is cleaned up substantially when a large number of inputs are sumed.
Always hugely knowledgeable, Jim. Well done.
Old 4 weeks ago
  #13
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jctaudiodesigns's Avatar
80b style mic preamp

Ok so I have just got back some prototype boards so I can change the mic preamp to a 80b. I am also going to fit transformers on the inputs and get the polarity right as these were built pin 3 hot originally. Will be testing next week. I can't wait!!!
Old 4 weeks ago
  #14
The 80B mic preamp is similar to the Flexmix. It's a two stage inverting opamp with dual pot feedback resistor gain control. It does have a major design flaw, a variable secondary loading effect that will cause overshoot at lower gains and undershoot at higher gains.

That can be corrected by changing the first opamp stage into a non-inverting stage with a fixed input impedance. Then the transformer secondary can be fitted with a RC network to smooth out the transient response. That way the transient response is correct and consistent at all gain settings. You will need to reverse the input connections as the polarity does change.
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