Rare Trident Model L29 Limiters - Caught in Nashville Flood

[thefastvinny]

Good to know. Thanks for the info. And it was an RCA 40362 by the way, typo earlier. I am so close to having them finished I don't want to put a component in backwards and cause more problems for myself. I am almost out of the water so to speak.

 

[joe-electro]

Since it's an FET limiter it should be fairly easy to troubleshoot.  Three things stand out as the most obvious reasons they're not compressing. First, the bias on the FET's has changed. The best way to measure the bias would be with a very high impedance meter such as an HP 410B or C VTVM.  There should be a small negative voltage (maybe 0.5 - 2 V depending on the FET, assuming it's N-channel) on the gate of the FET with no signal. If you know which pot adjusts the bias, adjust this pot to increase the bias a little bit (with a signal running through the unit) and see if there's any reduction in gain.  If the voltage on the gate changes but there's no gain reduction, then the FET's may be bad, which is the second glaring possibility.  The third is that the sidechain is not working properly.  If it has an external sidechan jack and/or switch/relay, this is the first place I would look.  Plug a loopback cable into the jack and see if the unit starts working.  Measure the switch and relay with an ohmmeter and make sure there's continuity in both positions.

But! Before doing all of this stuff make sure your supply voltages are correct. If one or both are way low, something is shorting and pulling them down.

If all else fails, send them to me and I'll look at them for you.

Thanks,

Joe

 

[QUEEF BAG]

i'm pretty sure you could use 2n2219A in place of the 40361
and a 2n2905A for the 40632 and be more than happy.

i have done that substitution in a few different trident units.

 

[billybuz]

Very cool!!!

For a very cold trail to follow, Funky Junk in France had a pair of these in stock a while back.... perhaps some schemo's there?

Personally, I'd wanna use the 40361 and 40362 to stay original for one, but also: they were very nice transistors  and key to the trident sound ( they are in the output of the A range and B range).


The unit, with a mix of IC's and discrete components, is very interesting and would be fun to see the schematic if you find it- or to reverse engineer( if you'd like).  did they use the IC's for a series 80 type output ( IC followed by PP transistors) or were the ic's for shaping the Gain reduction curves?

If you are looking to redo yourself then I'd say follow the funkyjunk trail.

However, if you want to have a certified Trident expert put the final touch and fix them, then I'd say contact Dave Michaels in LA.

He was the Trident guy in the USA( importer, Trident rep and tech( guru!!).. and knows everything about them- everything.

He is a great guy and you will know it is done correctly- or better yet the way Dave would have had them performing when he put them into service.

Good luck ( ... and if you  do find the schemo I'd love a copy  (please :  )))

 

[Kid Squid]

Hello Chaps, and a very Happy new year to you all !!!!

Vinny, I also have four of these limiters, without any documentation apart from the pin outs. I'm just wondering if you could help me out on something.
Would it be possible to get the info off the input and output transformers please !!!, It would be very much appreciated 

Anyway Chaps, here's the pin out info, courtesy of John Noll at Retromedia Sound Studios, NJ

*Trident 9054A  Pinouts:*

2 - 24V dc -

5 - 24V dc +

12 - Chassis Ground (NC)

13 - Signal INPUT ground

14 - Signal INPUT

16 - Link

17 - Link

18 - Link

20 - Link

23 - signal OUTPUT ground

24 - signal OUTPUT

Steve 

 

[amra]

Wow! I was looking for any infos about those trident compressors and I come to this!
Maybe I've the 4 pot version (CB-9064) as I posted here?
http://www.groupdiy.com/index.php?topic=42579.0
Looks like the same connector I have in my version, I really hope it use the same pinout as this one?!  :

 

[Kid Squid]

Hello Chaps,
Been doing a bit of digging regarding these Trident Limiters ( CB9054A/B ), and it seems that these were designed by Trident.
Amra's Limiters, ( CB9064A/B ) were designed, by ADR, as a generic limiter, which were also used in the Helios consoles of the same era. These are very closely based on the ADR 700 series compressor / limiter.
So, the digging continues................

Steve

 

[andre tchmil]

Hello Chaps, and a very Happy new year to you all !!!!

Vinny, I also have four of these limiters, without any documentation apart from the pin outs. I'm just wondering if you could help me out on something.
Would it be possible to get the info off the input and output transformers please !!!, It would be very much appreciated 

Anyway Chaps, here's the pin out info, courtesy of John Noll at Retromedia Sound Studios, NJ

*Trident 9054A  Pinouts:*

2 - 24V dc -

5 - 24V dc +

12 - Chassis Ground (NC)

13 - Signal INPUT ground

14 - Signal INPUT

16 - Link

17 - Link

18 - Link

20 - Link

23 - signal OUTPUT ground

24 - signal OUTPUT

Steve 

Digging up this old thread.
Are you sure they run on 24V ?

 

[beatnik]

has anyone managed to get schematics for this limiter module?

 

[guy_4]

Hello All,
Beatnik  wrote :
"  has anyone managed to get schematics for this limiter module?  "
But no answer... :'(
I am also in search of all and any technical documents on this unit.
I have two units to turn back to life…
Thanks
Best,
Guy