trident a range build

[dmp]

At long last, showing some pics of my Trident channel build. This is the second one I've built after working on developing this for, oh two years.
I used on board grayhill switches and added two frequencies per band from the original design.
A 3 pole grayhill to cover the mic/line switching and gain adjustments.
Developed the inductors with help from the drawing board and ChrioN.

 

[dmp]

The front

 

[spase]

Finalyyy ))

 

[okgb]

Looks good , nice work !  where does it fit sound wise with what you have ?

 

[Ptownkid]

MASSIVE pcb, love it!!!

 

[dandeurloo]

Looks great!  Glad to hear the project is moving along.

 

[dmp]

Thanks guys!

Looks good , nice work !  where does it fit sound wise with what you have ?

That's a tough question... will take me awhile to really get an idea about that.
I'll say it is very musical and flexible. My EQNs are the only comparison since the other EQs I have aren't so flexible. 
I heard a description of the Trident EQ that it is like four volume faders (for the 4 EQ bands).
I was using it this weekend for pre-EQ vocals for my plate reverb. It allows a lot of possibilities that sound good!
I'd love to build one with faders like an original, but it was plenty of work with just pots!

 

[dmp]

So more back story on this build.
I based this on one of the original Trident A Range consoles, the last one I think? The big blue one.
And the original documentation. A D-size original schematic and the original layout. So when I drew up the schematic and the layout I tried to stay as close as possible.
Also, examined several original channels. The caps through different channels on the original had been replaced. Some tants some electrolytics. Wima MKPs.

So I got some sample pcbs and built up a channel and brought it over to the studio for direct comparison to the board.
The conclusion was that it sounded very similar, except for the mid and midhigh (inductor based EQ channels). The low and high sounded extremely similar. The HPF and LPF sounded extremely similar.
Went back to the drawing board on the inductors. The inductances looked correct for hitting the frequencies, but something was wrong in the tone. I sent a high res picture of the inductors in the originals to ChrioN, and he identified that the core material was different than he used. The core material for the Trident was not typical. But he was able to get the cores and wound new inductors for my build.
After installing these and going back to the studio, the listening test was very successful. The original and my build sounded and behaved very closely - as closely as any two channels of the original anyway.

 

[dmp]

I had a question about the inductors for the trident EQ - so here is the description for my build.

 

[leadbreath]

wow! good to know that, what material did they use for thier cores?

 

[dmp]

N30 is a Nickle-Zinc material I think. Here is a datasheet from a different manufacturer (The original has a Sifam logo on the inductor).

 

[dmp]

Posting some build docs. Here is the BOM

 

[dmp]

Here is the schematic. Note that there are options on the gain switch and the EQ to customize or build as authentic. I used a single rotary switch for mic / line switching, but you can also build with a separate mic/line switch.
Similarly, you can build with 4 freq steps on the EQs, but I added 2 to make 6 freqs.
I chose a phase on mine, but there is the option for a pad or phase (I couldn't fit both on the pcb)