D-LA2A Support Thread

[srcalavera]

I´m finishing my D-LA2A board and starting with the transformer,
I managed to buy Jansen transformer and not sowter, not a matter of preference but opportunity.

I check both datasheet and can't figure out the relation between jensen and sowter transformers.
Do a quick search on internet and groupdiy and can't find it too (Damn I'm to dumb)

I Can't find any info about what color means.

So:

jt-11p-1
red - blk - whi - brn - yel - org
primary red to brn and secondary yel to org

sowter 4383
Brown (1) - pink (2) - green (3) - blue (4) - grey (5) - (6) black

jt-10k61-1m
grn - blk - blu - org - yel - brn - red
primary grn to blu and secondary org to red

sowter 8940
yellow (13) - green (15) - grey (10) - pink (9) - black (6)

could someone help me to make the right connections?

ps. yes I already check Jensen site to the circuitry modification, which I suppose must be done, right?

 

[hugo]

Hi,
Does somebody have a wiring scheme for Edcor in/out ? I still do not know what i am supposed to do with  the blk sowter footprints, and with the center taps od transfos (sowter do not have CT)..
I make a first try with skipping all center taps, and connecting primary and secondary as sowter. The sowter shield footprint has been connected to the ground.. Is there something wrong here ?

Thank you

 

[hugo]

Hi all,
is it possible to re upload the documents, all links are dead...
Thanks a lot

 

[[silent:arts]]

Hi all,
is it possible to re upload the documents, all links are dead...
Thanks a lot

Document / external links are working.
Internal forum links are dead.
Maybe Ethan is working on the forum software.
(I do NOT want to change all internal links again)

 

[hugo]

Hi,
WHere can i find those external working links ?..I searched but i could not find them..
Thank you

 

[[silent:arts]]

WHere can i find those external working links ?..I searched but i could not find them..

First post

 

[hugo]

WHere can i find those external working links ?..I searched but i could not find them..

First post

Dead links on first post :
Rx25 (TBD) & Meter callibration by SSLtech
Limiter Response Calibration (RV137/RV237)
Stereo Balance Adjust (RV103/RV203)
comments about Cx04 & Cx14 (aka Arco caps) by Kingston
some very important things that all should be awared by poctop

US BOM by azone

compiled informations from this thread in a single PDF by sonicwarrior

ty

 

[[silent:arts]]

Those are all internal links in this threat ...

 

[peterc]

Links are also dead for me.....

 

[[silent:arts]]

Links are also dead for me.....

Sure. For me too. Like all direct links to posts in the forum.
And all forum hosted profile pics, btw.

 

[hugo]

Sorry to annoy... but i would like to know if somebody can check this draw to tell me if my conections are good ?.. thank you

 

[[silent:arts]]

...
I make a first try with skipping all center taps, and connecting primary and secondary as sowter
...

Yes.
Ignore Center Taps, they are not used.
If your transformer has no shield winding / connector ignore it.
It is just a primary and a secondary winding, nothing complicated.

 

[dmp]

So I got all the bugs worked out in my build and have used it a few times at the studio. This is an amazing compressor! It glues bass into the mix.
I did a 2U build, with Jensen line inputs & edcor outputs. Added a SC HPF switch on the front with a freq adjustment on the back, as well as a zero calibration pot on the back.  Built the t4 cells in re-used relay enclosures.
Wonderful.
Thanks.

 

[djfatum]

 

[hugo]

Hi,
I finished my first D-la2a, great stuff!
But, i have some issue, about grounding i think:

- I have a noise appearing suddently at 80/90 gain (like pink noise), tu vu meter is completely over the +3  indication (will the mod 75k + 25k pot solve this ?).

- I have a hum and meter issue : When the unit is connected by xlr, i have -37db (on DAW) at 80 gain. The vu meter show -7db at 80 gain.
When i remove the XLR cable, the hum is increased ( -28db) but my vu meter shows 0 this time.

I made the wiring carefuly with shielded on pots, Limit/compress, link/dual, in/bypass. other cables are twisted, shortest as possible. I made the heater with not so big wires, and used lot of solder (can it be a source of issue).

Few general questions :

- Does all parts of enclosure must be connected together ? May i removed more paint on enclosure parts (behind pots and screws)
- Does XLR pin 1 have to be interconnected (and connected to the star ground ?) They are plastic xlr's and are not connected directly to the ground (the documents said it is not needed in that design)...
- What is a typical noise level on one channel with no input connected, at 80 gain ?

Thank you again for your support

 

[monophace]

I am also having issues with the potentiometers. I got once (by accident) a clean signal on left channel. But mostly it is distorted and very noisy.

I use a shielded audio kabel with 3 kabels inside, which connect Alpha Potentiometer pins 1,2,3 with connector pins 1,2,3. The shield is not connected. Should I use the shield instead of one of the cabels to connect pin 1?

 

[[silent:arts]]

Pin 1 of the potentiometers is connected to Ground and used for the shield.

 

[monophace]

Pin 1 of the potentiometers is connected to Ground and used for the shield.

My bad. I misunderstood the Poti pins. The pins are 1,2,3 when looking from the front. I was looking from the rear. Fixed it, and sound is clear now.

That made it clear to me: http://www.wikihow.com/Wire-a-Potentiometer

 

[monophace]

Another unit almost finished. Many thanks to Volker for your effort and support!

Still fixes todo:
- Humming on right channel (about -36dB)
- Zener diodes (NE2) wrong direction
- Meter not working with GR (VU works)

The gain reduction is very humble. I have not mesured, but would say only about 1-2 dB. Should the GR be drastic on this unit?

 

[PeteC]

Hi everyone,
Getting near the end of my build..
I have stuffed the board and now have the rest of my components and hardware to complete my build using Volker's excellent board and Franks superb case.

I am looking at the hook up information and wanted to know which wiring is critical to use shielded cable? There are many molex connections and I wanted to understand if most of these are un-shielded ?

Any advice very welcome !  Thanks
Pete